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The Social Structure and Ecology of Elephant-Shrews
... All these giant sengi species are diurnal, and frequently observed as solitary individuals, rarely as pairs. Individuals forage in deep leaf litter on forest floors, often under relatively dense vegetation cover, and extrapolating from the best-studied R. chrysopygus (Rathbun, 1979) and observations of R. petersi, R. cirnei, and R. udzungwensis (NJC and FR, pers. obs.), the flexible snout is used to probe invertebrates in dense leaf litter, and the long tongue is extended to flick and draw in prey. ...
... obs.), the flexible snout is used to probe invertebrates in dense leaf litter, and the long tongue is extended to flick and draw in prey. The forefeet are used for moving away the leaf litter and debris whilst foraging, as well as for holding large prey (Rathbun, 1979). F I G U R E 1 Distribution of giant sengis (genus Rhynchocyon) in central to eastern Africa, following Agwanda et al. (2021): (A) Inset of the location in Africa that is focused in the larger map (B) showing distribution of all species and their respective races. ...
... Determining the type of symbiosis involved based solely on camera-trap photographs is difficult. However, the field observations by NJC, KN and TJ, and a more comprehensive field study by Rathbun (1979) on R. chrysopygus, indicate that the interaction is likely commensal. The sengis are apparently not harmed nor do they benefit from the interaction whereas the birds benefit from feeding on insects and other invertebrates disturbed by the sengis. ...
Using camera traps and direct observations, we recorded interactions between three species of giant sengi ( Rhynchocyon sp.) and two insectivorous bird species from six forests in Tanzania. In all instances, the birds closely followed the giant sengis who were moving and foraging in the leaf litter. Given that the two bird species are insectivorous and follow ant swarms to obtain flushed prey, these interactions suggest that following sengis represents an adaptive foraging strategy. Our observations indicate that these behaviors and associations may be more pervasive than previously thought.
Abstract in Swahili is available with online material
... The mammalian order Macroscelidea (elephant-shrews or sengis) includes 19 extant species in four genera, all occurring in Africa, ranging in body mass from 27 to 700 g (Rathbun & Dumbacher, 2015;Rovero et al., 2008) and occupying a diversity of habitats including deserts, semi-deserts, savannahs, rocky mountains, lowland forests, and tropical rain forests (Kingdon et al., 2013;Rathbun, 1979). ...
... The long-held assumption that all elephant-shrews are monogamous might have led to an underappreciation of variation in their social systems. The last detailed review on monogamy in elephantshrews was published more than 40 years ago (Rathbun, 1979), and was updated within the discussion of a more recent case study (Rathbun & Rathbun, 2006). Therein, the importance of considering intra-specific variation for understanding the social systems of elephant-shrews, which were still considered to be all monogamous, was emphasized (Rathbun & Rathbun, 2006). ...
... For the care system, peer-reviewed literature from studies conducted in the field and in captivity were used. Searches were made using the following key words: "maternal care," "paternal care," "offspring," "direct paternal care," "indirect paternal care," and "absentee strategy" which are common terms for Macroscelidea (Rathbun, 1979). Indirect paternal care represents behaviors shown by the fathers independent of the presence of offspring which are beneficial for the offspring (while direct paternal care is a direct response to the presence of offspring) (Kleiman, 1977). ...
Elephant‐shrews (Macroscelidea) have long been considered the only mammalian order to be completely monogamous, based on observations of their pair‐living social organization. We reviewed primary studies on the four components of social systems (social organization, mating system, social structure, and care system) in elephant‐shrews to evaluate whether they truly are monogamous. To identify gaps in our knowledge of their social system, we reviewed evidence for a pair‐living social organization, mate fidelity (mating system), pair bonds (social structure), and biparental care (care system). Field data were available for eight species and seven were often pair‐living. However, these seven species exhibited intra‐specific variation in social organization; two of these species were also solitary living, two species were also group‐living, and the remaining three species were both solitary and group‐living. The eighth species was exclusively solitary. We reconstructed the ancestral social organization of Macroscelidea using Bayesian phylogenetic mixed‐effects models and found that variable social organization, rather than exclusive pair‐living, was the most likely ancestral state, though there was high uncertainty. No socio‐ecological factors (body size, population density, and habitat) predicted a specific social organization. Observations of mating have been rare, such that no firm statements can be made. However, one unpublished study indicated high levels of extra‐pair paternity. Regarding social structure, there was no evidence of pair‐bonding, but there was evidence of mate guarding. Only maternal care has been observed, with females having very short nursing bouts. Evidence suggests that despite having often a pair‐living form of social organization, Macroscelidea should not be described as a monogamous order, as little or no evidence supports that designation, nor are they exclusively pair‐living (social organization) and we urge further field studies on Macroscelidea social systems. Elephant shrews have often been claimed to be the only monogamous mammalian order. Here we show that this statement is wrong. Our literature review shows that no data are available to determine their mating system and that their social organization is variable, often including pair‐living.
... While sengis of the subfamily Rhynchocyoninae (Giant Sengis) are diurnal, most species of the subfamily Macroscelidinae (Soft-furred Sengis) are polycyclic with activity during day and night, but with peak activity around twilight times (i.e., dawn and dusk, crepuscular) and, depending on the species, with more or less nocturnal tendencies (Rathbun, 1979(Rathbun, , 2009Rathbun & Dumbacher, 2015). Thus, their eyes function well both, in the dim light of the night, but also in the bright light of the day. ...
... Our aims were to experimentally test colour vision capabilities in two species of sengis, the Round-eared elephant-shrew, Macroscelides proboscideus (polycyclic, mainly crepuscular with nocturnal tendencies; Roxburgh & Perrin, 1994) and the Rufous elephant-shrew, Elephantulus rufescens (polycyclic, mainly crepuscular; Rathbun, 1979). As also other Afrotheria (manatees, elephants, rock hyraxes) with activity during the day and night (Coe, 1962;Wyatt & Eltringham, 1974;Montgomery et al., 1981) are most probably dichromats (Yokoyama et al., 2005), as manatees have been identified by behavioural experiments to perceive blue and green (Griebel & Schmid, 1996), and as sequence data and opsin in vitro expression assays suggested maximum sensitivity values in the blue-green and UV wavelengths for one species of sengi (E. ...
... The species is mostly crepuscular with nocturnal tendencies, and less active in the morning and rarely in the afternoon (Woodall et al., 1989;Roxburgh & Perrin, 1994). Elephantulus rufescens (tribe Elephantulini) naturally occurs in East Africa (Koontz & Roeper, 1983) and is active at all times, with peak activity at dawn and dusk (crepuscular) and least activity at midday (Rathbun, 1979). ...
Little research has been conducted on the senses of sengis (elephant-shrews, Macroscelidea, Afrotheria, Mammalia); behavioural investigations about the animals' vision are completely missing. Other Afrotheria (manatees, elephants, tenrecs, rock hyraxes) are dichromats, having two types of cone photoreceptors in the retina. We tested the hypotheses of dichromatic colour vision in sengis. With choice experiments, we examined the potential of two sengi species to discriminate between trained colours (blue, green, red) and different shades of grey, and to differentiate between trained UV-reflecting (high UV reflectance) and UV-absorbing (low UV reflectance) plates. Both sengi species recognised blue and green and could distinguish them from all shades of grey. The ability to perceive red and ultraviolet could not be proven. Thus, the sengis are most likely dichro-mats based on green and blue sensitive receptor types. We discuss protective mechanisms in the lens as a UV filter explaining maximum sensitivity in the UV suggested for another sengi species after in vitro expression assays.
... All sengis studied so far are socially monogamous with pairs that mate for life and that share relatively well-defined home ranges (Rathbun, 2009). Most of these taxa give birth to highly precocial neonates some of which are able to sprint within one hour of parturition (Rathbun, 1979;Rathbun & Rathbun, 2006). The sengi lineage is most closely related to tenrecs, golden-moles, and aardvarks (Meredith et al., 2011;Springer et al., 2003) and the fossil record of Macroscelidea documents a history of endemism on the African continent that extends back at least 45.6 million years (Hartenberger, 1986;Holroyd, 2010;Seiffert, 2010a). ...
... However, field notes indicate that the two differ in their habitats-the Somali Sengi was found in areas with rocky terrain and the Somalian Rufous Sengi among bushes on sandy soils (Corbet & Hanks, 1968). Elsewhere in Africa, the habitats of Rufous Sengis are well-understood; they occur in arid woodlands and bushlands with compact sandy soils, open canopies, scrub vegetation, and very little grass (Koontz & Roeper, 1983;Perrin & Rathbun, 2013;Rathbun, 1979). It seems that the Somalian Rufous Sengi and other Rufous Sengi subspecies are consistent in their habitats and substrate use. ...
... The late Miocene is associated with a reduction in closed canopy forests and the expansion of open landscapes and C4 grasslands in East Africa (Ségalen, Lee-Thorp & Cerling, 2007). Rhynchocyon species require habitats with dense leaf litter (i.e., canopy forests and dense woodlands) which is used to build nests for neonates and for nightly sheltering (Rathbun, 1979(Rathbun, , 2009. Extinct Rhynchocyoninae taxa that predate the crown-clade could have been pressured by expanding grasslands and the spread of the subfamily's geographic range could have been, and is, constrained by forest contiguity. ...
The Somali Sengi or Somali Elephant-shrew ('Elephantulus' revoilii, Macroscelidea, Mammalia) has been considered a "lost species" and is primarily known from about 39 museum specimens, with no new vouchered occurrence records since the early 1970s. The scientific literature contains no data concerning living Somali Sengi individuals and the species’ current Data Deficient conservation status is attributable to an absence of modern information. Almost everything that has been published about the species is derived from anatomical examinations of historic specimens, gleaned from museum collection notes, or inferred from the known habits and ecology of other sengi taxa. Here we report new evidence that the Somali Sengi is currently extant. These data include voucher specimens, georeferenced occurrence localities, body measurements, habitat parameters, and DNA sequences. While the species is historically documented as endemic to Somalia, these new records are from the neighboring Republic of Djibouti and thus expand the Somali Sengi's known range in the Horn of Africa. Furthermore, Djiboutian locality data near international borders suggests that the Somali Sengi is also a current inhabitant of both Somalia and Ethiopia. Criteria that inform conservation status assessments (e.g., suitable habitat contiguity and occurrence in wildlife protected areas) can be positively characterized in Djibouti and therefore bode well for the survival of the Somali Sengi species. New data also inform previously undocumented substrate and sheltering affiliations. DNA analyses indicate that the Somali Sengi is a descendant of the Macroscelidini lineage and therefore reveal that the species' referral to the genus Elephantulus is incompatible with sengi phylogeny. This taxonomic issue is resolved by recognizing a new genus replacement and recombinant binomial that redesignates the Somali Sengi as Galegeeska revoilii (gen. nov., nov. comb). An analysis of ancestral biogeography suggests that the Somali Sengi has inhabited the Horn of Africa for more than 5.4 million years – and the recognition of the species’ phylogenetic ancestry appends the already remarkable biogeographic story of the Macroscelidini tribe.
... Petrodromus tetradactylus is oligo-ovulating (Tripp 1971). Although female 4-toed elephant-shrews typically carry single embryos and produce single young (Brown 1964;Rathbun 1979;Tripp 1971), 2 embryos occurred in 1 of 2 females from Zambia (Sheppe 1973) and in 2 of 3 females from Zimbabwe (Smithers and Wilson 1979). ...
... 31.5 g, with a daily gain of ca. 2 g (Tripp 1972). P. tetradactylus has been maintained in captivity (Ansell and Ansell 1969;Rathbun 1979;Tripp 1972), but it has not conceived in captivity (Nicoll and Rathbun 1990). Females captured in late pregnancy are prone to abort (Kingdon 1974;G. ...
... Better survival can be achieved by placing unbaited live traps on their paths (Ansell and Ansell 1969;Tripp 1972) or by chasing animals into fine nets (FitzGibbon 1995;Loveridge 1922). Colored ear-tags (Rathbun 1979) and radio-collars (FitzGibbon 1995) have been successfully used to mark 4-toed elephant-shrews. ...
... Globally, the East African coastal forests remain among 25 outstanding biological hotspots containing exceptional levels of endemism of major taxa (Myers et al., 2000). Among these endemic taxa are species of the genus Rhynchocyon (Rathbun, 1979). ...
... Little is known about this species because detailed field studies are very scarce (Rathbun & Butynski, 2008). Most aspects of its natural history are assumed to be similar to the Golden-rumped sengi (Rathbun, 1979), which are diurnal and live in monogamous pairs with defined territories of about 1.5 ha. They build nests for shelters and each pair maintains 6 or 7 nests in a territory using several of them at one time. ...
... Trapping of R. petersi was conducted between October 2010 and May 2014. Trapping sengis is difficult as no bait able to attract sengis is known (Rathbun, 1979;Sabuni, Beddetti & Leirs, 2011). We used two trapping methods, wire-mesh and fish-net traps, in order to enhance the catch rate of live individuals: (1) twenty single-door non-collapsible wire-mesh traps (Tomahawk, model 102, 13 9 13 9 40.5 cm) and 25 medium collapsible single-door wire-mesh traps (Havahart Trap, 20 9 61 9 20 cm) were set in the trails and paths in the forests; (2) fifty nets laid following Rathbun (1979) in a narrow transect line of about 100 m. ...
The black and rufous sengi Rhynchocyon petersi is restricted to the Eastern Arc Mountains and coastal forests of East Africa and considered vulnerable because of habitat fragmentation and degradation. Coastal forests are believed to have been isolated from each other for thousands of years due to climatic changes. Since R. petersi is described as strongly dependent on its forest habitat, we hypothesized that R. petersi from different forests would show genetic divergence. We investigated the genetic structure and diversity of this species in four coastal forests in Tanzania using eight microsatellites and cytochrome b sequences. In total, 45 individuals were captured after strenuous sampling efforts. For comparative purposes we also sequenced the cytochrome b of 57 individuals from a sympatric rodent forest species, Beamys hindei. The results indicate extant R. petersi have descended from a single population of high effective size (Ne) with no forest-distinctive signal. In contrast, B. hindei is more genetically structured: Although the most common haplotype is found in the three closest forests, each forest harbours private haplotypes. Moreover, B. hindei Ne appeared 10 times smaller than R. petersi in Zaraninge forest. While B. hindei results are consistent with the scenario of long-term isolation of coastal forests, the R. petersi are not. We suggest R. petersi may less depend on forest habitat than previously suspected, consistent with anecdotal reports of sengis nesting in intervening agricultural habitat. From a conservation viewpoint, this sengi species therefore appears robust to the current spatial and temporal scale of habitat fragmentation.
... Globally, the East African coastal forests remain among 25 outstanding biological hotspots containing exceptional levels of endemism of major taxa (Myers et al., 2000). Among these endemic taxa are species of the genus Rhynchocyon (Rathbun, 1979). ...
... Little is known about this species because detailed field studies are very scarce (Rathbun & Butynski, 2008). Most aspects of its natural history are assumed to be similar to the Golden-rumped sengi (Rathbun, 1979), which are diurnal and live in monogamous pairs with defined territories of about 1.5 ha. They build nests for shelters and each pair maintains 6 or 7 nests in a territory using several of them at one time. ...
... Trapping of R. petersi was conducted between October 2010 and May 2014. Trapping sengis is difficult as no bait able to attract sengis is known (Rathbun, 1979;Sabuni, Beddetti & Leirs, 2011). We used two trapping methods, wire-mesh and fish-net traps, in order to enhance the catch rate of live individuals: (1) twenty single-door non-collapsible wire-mesh traps (Tomahawk, model 102, 13 9 13 9 40.5 cm) and 25 medium collapsible single-door wire-mesh traps (Havahart Trap, 20 9 61 9 20 cm) were set in the trails and paths in the forests; (2) fifty nets laid following Rathbun (1979) in a narrow transect line of about 100 m. ...
Abstract
The black and rufous sengi Rhynchocyon petersi is restricted to the Eastern Arc
Mountains and coastal forests of East Africa and considered vulnerable because of
habitat fragmentation and degradation. Coastal forests are believed to have been
isolated from each other for thousands of years due to climatic changes. Since
R. petersi is described as strongly dependent on its forest habitat, we hypothesized
that R. petersi from different forests would show genetic divergence. We investi-
gated the genetic structure and diversity of this species in four coastal forests in
Tanzania using eight micro satellites and cytochrome b sequences. In total, 45 indi-
viduals were captured after strenuous sampling efforts. For comparative purposes
we also sequenced the cytochrome b of 57 individuals from a sympatric rodent for-
est species, Beamys hindei. The results indicate extant k. petersi have descended
from a single population of high effective size (Ne) with no forest-distinctive sig-
nal. In contrast, B. hindei is more genetically structured: Although the most com-
mon haplotype is found in the three closest forests, each forest harbours private
haplotypes. Moreover, B. hindei Ne appeared 10 times smaller than R. petersi in
Zaraninge forest. While B. hindei results are consistent with the scenario of long-
term isolation of coastal forests, the R. petersi are not. We suggest R. petersi may
less depend on forest habitat than previously suspected, consistent with anecdotal
reports of sengis nesting in intervening agricultural habitat. From a conservation
viewpoint, this sengi species therefore appears robust to the current spatial and
temporal scale of habitat fragmentation.
... From the earliest studies of sengis (Sauer, 1973;Rathbun, 1979), it was recognized that their combined life history traits formed a unique adaptive syndrome, not seen in any other mammals in other biogeographic regions of the world. The syndrome blends life history strategies usually associated with ant-eaters and some antelopes, including a diet of invertebrates with an associated long nose and tongue and small mouth, highly cursorial locomotion, small precocial litters, absentee maternal care, lack of nest-use (Macroscelidinae only), and social monogamy. ...
... The syndrome blends life history strategies usually associated with ant-eaters and some antelopes, including a diet of invertebrates with an associated long nose and tongue and small mouth, highly cursorial locomotion, small precocial litters, absentee maternal care, lack of nest-use (Macroscelidinae only), and social monogamy. These traits do not vary greatly among the species so far studied, despite the considerable variation in their size and habitats (Rathbun, 1979;Rathbun, 2009). ...
... When it was found that some sengis were socially monogamous (Rathbun, 1979), which is unusual in mammals (Komer & Brotherton, 1997), additional studies were completed to better understand the evolution of this social organization (FitzGibbon, 1995;Ribble & Perrin, 2005;Rathbun & Rathbun, 2006;Schubert et al., 2009;Oxenham & Perrin, 2009). One of the main focuses of these studies has been home range characteristics, but other aspects of their life history have been documented incidentally, such as the unusual sheltering habits among the Macroscelidinae. ...
To understand habitat use by the newly described Etendeka round-eared sengi (Macroscelides micus) in northwestern Namibia, we radio-tracked five individuals for nearly a month.Home ranges (100% convex polygons) in the rocky desert habitat were remarkably large (mean 14.9 ha) when compared to sengi species in more mesic habitats (<1.5 ha). The activity pattern of M. micus was strictly nocturnal, which contrasts to the normal diurnal or crepuscular activity of other sengis. The day shelters of M. micus were under single rocks and they likely were occupied by single sengis. One tagged sengi used 22 different day shelters during the study. On average, only 7% of the day shelters were used more than once by the five tagged sengis. The shelters were also unusual for a small mammal in that they were unmodified in terms of excavation or nesting material. Shelter entrances were significantly oriented to face south by south west (average 193°), away from the angle of the prevailing midday sun. This suggests that solar radiation is probably an important aspect of M. micus thermal ecology, similar to other sengis. Compared to published data on other sengis, M. micus generally conforms to the unique sengi adaptive syndrome, but with modifications related to its hyper-arid habitat.
... Elephant-shrews, or sengis, are an endemic group of African small mammals with all extant species (with the exception of Elephantulus rozeti) confined to sub-Saharan Africa (Corbet & Hanks 1968) ( Fig.1.1). This enigmatic assemblage has intrigued researchers in the past and has been described as "secretive", "unusual" and of "evolutionary interest" (van der Horst 1946;Rathbun 1979). ...
... The taxonomic status of this order has received much attention with studies on living as well as fossil Macroscelidea included in the works of Butler & Hopwood (1957), Patterson (1965), Corbet & Hanks (1968), Butler & Greenwood (1976), Butler (1978) and Rathbun (1979). ...
... Elephant-shrews are mainly insectivorous, notwithstanding their probable herbivorous ancestry suggested by the retention of a caecum facilitating hindgut fermentation in living Macroscelidea (Woodall & Mackie 1987) and the apparent adaptation to a herbivorous diet in the extinct Myohyracinae † (Butler 1984). They feed largely on ants, termites and other small invertebrates (Rathbun 1979;Kerley 1995). However, significant percentages of herbage and seeds/fruit are consumed by a number of extant species (Sauer & Sauer 1972;Rathbun 1979;Kerley 1995). ...
... Elephant-shrews or sengis (KINGDON, 1997) are a unique group of small mammals with no ecological or behavioral equivalents outside of Africa. All species feed largely on invertebrates (RATHBUN, 1979;CHURCHFIELD, 1987;KERLEY, 1995), and all are highly cursorial and capable of very fast locomotion (RATHBUN, 1979). The smaller species usually produce only one or two offspring that are born in a very precocial state. ...
... Elephant-shrews or sengis (KINGDON, 1997) are a unique group of small mammals with no ecological or behavioral equivalents outside of Africa. All species feed largely on invertebrates (RATHBUN, 1979;CHURCHFIELD, 1987;KERLEY, 1995), and all are highly cursorial and capable of very fast locomotion (RATHBUN, 1979). The smaller species usually produce only one or two offspring that are born in a very precocial state. ...
... These life histories are more similar to small-bodied cursorial herbivores than similar-sized small mammals. Behaviorally, all of the 15 species of sengis from 4 genera are suspected to be monogamous (RATHBUN, 1979). Of the species studied in detail, male and female pairs have overlapping territories that result in monogamous associations, probably for life (SAUER, 1973;RATHBUN, 1979;FITZGIBBON, 1995FITZGIBBON, , 1997. ...
Understanding the costs and benefits of defending solitary females, or mate guarding, may be the key to understanding the evolution of monogamy in most mammals. Elephant-shrews, or sengis, are a unique clade of small mammals that are particularly attractive for studies of mate guarding. We studied the spatial organization of Eastern Rock Sengis (Elephantulus myurus) in KwaZulu-Natal, South Africa, from August - December 2000. Our objectives were to describe the home ranges of males and females using radiotelemetry, noting the sizes and overlap of adjacent ranges and how the spatial organization changes through time. Males and females were spatially associ- ated in monogamous pairs despite the fact that males contributed no obvious direct care to offspring. These monog- amous associations persisted despite the fact that some males had home ranges large enough to encompass multiple females. Males also had more variable ranges, perhaps because they spent more time at the periphery of their ranges exploring for the presence of additional females. There was likely competition for females, as range shifts were observed when male territory holders died or disappeared. It seems likely that this species is a model study organ- ism to investigate the costs and benefits of mate guarding.
... For shelter, the giant elephant-shrews build nests. The dimensions of their shelters are typically one meter wide with a body-sized bowl of 20cm long, 15cm wide and 10cm deep (RATHBUN, 1979). Giant elephant-shrews live in monogamous pairs with defined territories and therefore each animal can make and maintain up to ten nests in one territory with several nests in use at one time (FITZ- GIBBON & RATHBUN, 1994). ...
... Giant elephant-shrews live in monogamous pairs with defined territories and therefore each animal can make and maintain up to ten nests in one territory with several nests in use at one time (FITZ- GIBBON & RATHBUN, 1994). Their territories are typically about 1-1.7 hectare (RATHBUN, 1979). Because of their dependence on undisturbed forest and their large territo-ries, their presence is an indication of a healthy forest ecosystem. ...
... All of these surveys of R. petersi were conducted over short periods of time and ideally longer studies should be conducted. However, in general Rhynchocyon populations do not vary substantially over time (RATHBUN, 1979) so we are confident in our relative comparisons between forests. ...
The objective of this study was to determine the density and habitat preference of the Black-and- rufous elephant-shrew (Rhynchocyon petersi) in Chome Forest Reserve, Tanzania. Chome Forest (143km2) is located in the South Pare Mountains and provides critical habitat for endangered R. petersi. Twelve 300m transects were cut through the centre of the forest in an east-west direction and the number of elephant-shrew nests within 2.5 meters on each side of the transects was recorded. The mean number of nests per 100m transect (0.39 ± 0.47 (1SE)) translated to a density estimate of 19 elephant-shrews per km2 (SE=23). Nest sites tended to be found in areas with greater than expected cover at the low (
... Recently, the North African sengi has undergone a radical phylogenetic change and is now placed in a monotypic genus (Dumbacher et al. 2016). Like other Macroscelidea, the species is primarily insectivorous (Rathbun 1979;Wester 2010). This animal has its specialist ectoparasites and endoparasites (Beaucournu and Launay 1990;Orecchia et al. 1964). ...
... We observed specimens being active at all times of the day, and only rarely at night. Crepuscular activity was previously reported for most soft-furred sengis (Neal 1995;Rathbun 1979;Ribble and Perrin 2005;Woodall et al. 1989). Moreover we did not comfirm whether the North African sengi lives in colonies or in pairs and interaction between individuals was rarely observed. ...
The North African sengi (Petrosaltator rozeti syn. Elephantulus rozeti) is a small mammal endemic to the Maghreb area, and is one of the least studied mammals in North Africa. Little is known about its status, habitat preference, and distribution across large areas of its range. This work provides a detailed geographical and ecological distribution of the species in Tunisia based on 200 surveyed sites throughout the country with 103 positive occurrence records. We also used species distribution modelling to assess the habitat suitability of the species. P.rozeti showed a heterogeneous bioclimatic niche, with a presence in the semi-arid, arid and Saharan bioclimatic zones. But the species’ distribution seems to be limited to the main mountain ranges of Tunisia. This was also confirmed by habitat suitability modeling where the elevation was the most informative predictor variable. Our work also show some first recorded ecological traits, confirms the rock-dwelling specialist nature of the species and debate its endemism to mountain ecosystems.
... Sengis have multiple remarkable features that, in combination, distinguish them from other mammals. All have elongated, highly flexible noses and extended hindlimbs resembling those of antelopes and allowing a swift saltatorial, ungulate-like gait (Rathbun, 1979(Rathbun, , 2009b. The species for which sufficient knowledge exists predominantly feed on insects, have a life-long monogamous lifestyle and give birth to highly precocial neonates to whom they provide minimal parental care (Heritage et al., 2020;Rathbun and Rathbun, 2006;Rathbun, 1979Rathbun, , 2009b. ...
... All have elongated, highly flexible noses and extended hindlimbs resembling those of antelopes and allowing a swift saltatorial, ungulate-like gait (Rathbun, 1979(Rathbun, , 2009b. The species for which sufficient knowledge exists predominantly feed on insects, have a life-long monogamous lifestyle and give birth to highly precocial neonates to whom they provide minimal parental care (Heritage et al., 2020;Rathbun and Rathbun, 2006;Rathbun, 1979Rathbun, , 2009b. Some species maintain paths within their well-defined territory by clearing them from organic litter and small stones (Rathbun, 2009a). ...
Sengis (order Macroscelidea) are small mammals endemic to Africa. The taxonomy
and phylogeny of sengis has been difficult to resolve due to a lack of clear morphological apomorphies. Molecular phylogenies have already significantly revised sengi systematics, but until now no molecular phylogeny has included all 20 extant species. In addition, the age of origin of the sengi crown clade and the divergence age of its two extant families remain unclear. Two recently published studies based on different datasets and age-calibration parameters (DNA type, outgroup selection, fossil calibration points) proposed highly different divergent age estimates and evolutionary scenarios. We obtained nuclear and mitochondrial DNA from mainly museum specimens using target enrichment of single-stranded DNA libraries to generate the first phylogeny of all extant macroscelidean species. We then explored the effects of different parameters (type of DNA, ratio of ingroup to outgroup sampling, number and type of fossil calibration points) and their resulting impacts on age estimates for the origin and initial diversification of Macroscelidea. We show that, even after correcting for substitution saturation, both using mitochondrial DNA in conjunction with nuclear DNA or alone results in much older ages and different branch lengths than when using nuclear DNA alone. We further show that the former effect can be attributed to insufficient amounts of nuclear data. If multiple calibration points are included, the age of the sengi crown group fossil prior has minimal impact on the estimated time frame of sengi evolution. In contrast, the inclusion or exclusion of outgroup fossil priors has a major effect on the resulting node ages. We also find that a reduced sampling of ingroup species does not significantly affect overall age estimates and that terminal specific substitution rates can serve as a means to evaluate the biological likeliness of
the produced temporal estimates. Our study demonstrates how commonly varied
parameters in temporal calibration of phylogenies affect age estimates. Dated
phylogenies should therefore always be seen in the context of the dataset which was used to produce them.
... is the reason for their having scented trails, which they use for checking up on each other's whereabouts (Komer & Brotherton, 1997;Rathbun, 1979;Rathbun & Redford, 1981). In carnivores, a well-developed olfactory cue is required in tracking and catching prey (Walker, 1975), whereas in herbivores, the role of olfaction mainly revolves around mating and neonatal care (Levy, Keller, & Poindron, 2004). ...
... Fossil data by Patterson (1965), blood protein studies by Goodman (1975) and behavioural work by Rathbun (1979) show elephant shrews to be a unique monophyletic taxon with only plesiomorphic similarities to the Insectivora. Evolutionary work reports indicate that the ancestors of the living insect-eating elephant shrews were herbivorous and shared the same morphological class with rabbits and rodents (Butler, 1995;Woodall, 1987). ...
Sengis are eutherian insectivores belonging to superorder Afrotheria, a recently defined clade of mammals that diverged from other placentals over 100 million years ago. In this study, a histological and ultrastructural analysis was carried out on the olfactory mucosa (OM) of the rufous sengi (Elephantulus rufescens) and the data were compared with those reported earlier in the dog (Canis familiaris) and the sheep (Ovis aries), whose dietary lifestyles are carnivorous and herbivorous, respectively. Qualitatively, the microstructure of the sengi's OM was basically similar to that of the other eutherian mammals except for differences in the pattern of cilia projection from the dendritic knobs of the olfactory receptor neurons (ORNs) and distribution of Bowman's glands within the lamina propria of the OM. On morphometry, significant differences (p < .05) were recorded with respect to olfactory epithelial (OE) thickness between the sengi (65.4 ± 2.6 μm) and the other species. ORN packing density and cilia number/ORN knob varied markedly only between the sengi (73.8 ± 5.4 mm-2 × 103and 15 ± 4, respectively) and the sheep. No remarkable differences were noted in regard to ORN bundle diameters between sengis (62.7 ± 12.5 μm) and the other species. The observed differences in OM structural refinement may be attributed to olfactory function demand levels related to feeding lifestyles and ecology. Myrmecophagous insectivory, social monogamy, absentee maternal care and exposed sheltering habits are behavioural features that may warrant substantial OM modification in sengis.
... Listed here are only some of the most often cited publications that emphasised the distinctiveness of sengis in the fields of morphology, reproduction, physiology and behavioural ecology. Earlier works also included natural history (Kingdon 1984), morphology and taxonomy (Corbet & Hanks 1968), home range use and social structure (Sauer & Sauer 1972; Rathbun 1979), reproductive physiology and genital morphology (Tripp 1971; Woodall 1995) as well as ecology and reproduction (Neal 1982; FitzGibbon 1995). The evolutionary importance of morphology was emphasised in several studies on fetal membranes (Mess & Carter 2006) and placental morphology (Odour-Okelo, Katema & Carter 2004). ...
... For mammals in general, longevity records in captivity often exceed the lifespan of free-ranging specimens. Rathbun (1979), for instance, expected four to five years lifespan for R. chrysopygus, based on his observations in the wild. Some years later a wild-caught specimen reached the age of almost 11 years at Frankfurt Zoo. ...
Olbricht, G. & Sliwa, A. 2014. Elephant shrews (sengis) - neither rodent nor shrew: A historical perspective.
Navors. nas. Mus., Bloemfontein 30(2): 18-30.
We provide an overview of the family Macroscelididae,
commonly known as elephant shrews or sengis, starting with their fossil history in the mid-Cretaceous period to
their phylogenetic placement in the supercohort Afrotheria. The currently accepted taxonomy of modern
macroscelids, with four genera and 18 species, is presented. A summary of their current conservation status in the
wild, according to the 2012 Red List of Threatened Species, is also provided. This is followed by an overview of
past and present research relevant to: i) the history of sengis in captivity, ii) the establishment of breeding colonies,
iii) their role and value in zoological collections and, iv) their contribution to research into longevity, reproductive
biology and postnatal development of small mammals.
Keywords: Macroscelidea, elephant shrews, sengis, Afrotheria, captive breeding
... It occurs in forested areas of Zambia, Malawi, Tanzania, and Mozambique, and extends east into Uganda nearly to the Victoria Nile River and to the coast in Tanzania and Mozambique (Rathbun & Nyari, 2012). The six subspecies show variable distinct patterns of dorsal longitudinal lines or stripes and spots (thus the name chequered sengis), as well as allopatric distributions, which together are the basis for their taxonomy (see colour plate and distribution maps for subspecies in Corbet & Hanks, 1968 (Rathbun, 1979), adjacent to the Rio Mareja, where giant sengis had been sighted in July and August 2010 (PGRC, personal observation). ...
... Rhynchocyon does not normally build or use trails (Rathbun, 1979), but where the fourtoed sengi (Petrodromus tetradactylus Peters, 1846) is syntopic, as at Mareja, Rhynchocyon will sometimes use the trails that Petrodromus builds and maintains. We set Tomahawk traps on Petrodromus trails, and to minimise injury to captured animals, we checked the traps every 2-3 hours during daylight. ...
The sengis (elephant-shrews) of Mozambique are poorly known, especially the taxonomic status of the giant sengis, genus Rhynchocyon Currently, Rhynchocyon from Mozambique are thought to be chequered sengis, R. cirnei with specimens from the central coastal areas being placed in the subspecies R. c. cirnei, while the subspecific status of those from north-eastern areas has not been determined. To resolve this taxonomic ambiguity, we collected voucher specimens from north-eastern Mozambique. Based on a comparison of pelage patterns and colouration, features that are currently used to distinguish taxa in the genus Rhynchocyon, specimens from all of coastal Mozambique show minor variation, but are similar enough to indicate that they all are referable to R. c. cirnei.
... The gestation period for the species reported here is not precisely known; however, all pregnant T. afra gave birth within 18 days of capture, while A. subspinosus and E. edwardii produced young at intervals up to 30 days from capture. This corresponds with observations of a short gestation period for T. brantsii (22 days) and T. leucogaster (28 days) (SCOTT 1979), longer gestation period (45 days) in A. dimidiatus (AL-KHALILI and DELANY 1986), and a gestation period longer than 50 days in E. rufescens (NEAL 1982;RATHBUN et al. 1981), E. intufi (TRIPP 1972) and Macroscelides proboscideus (RATHBUN 1979). Litter sizes were smaller for the serni-precocial A. subspinosus and precocial E. edwardii than for the altricial T. afra, and individual mass and litter mass relative to adult mass were more than two times greater in the serni-precocial and precocial species than in T. afra. ...
... Three Otomys species and three Acomys species have precocial young (NEAL 1990), with A. subspinosus and A. hystrella (HUBBARD 1972) bearing semi-precocial young. All elephant-shrew species are reported to bear precocial young (RATHBUN 1979). The designation of "semi-precocialiry " is unclear: NEAL (1990) classifies Aethomys species as altricial despite the fact that all developmental events such as eye opening, incisor eruption, and hair growth occur earlier than in Tatera species. ...
Four species of small mammals occur sympatrically in an arid area of the southwestern Cape Province. Females of all four species produced young after capture during a field excursion in September 1990. Postnatal development of three species, namely Tatera afra, Acomys subspinosus and Elephantulus edwardii, is reported for the first time, and compared with recorded data for the fourth species, Aethomys namaquensis.
T afra produced altricial, nipple-clinging young, while young of E. edwardii wqere precocial and did not nipple-cling. A subspinosus produced semi-precocial young which grew rapidly. Young of A. namaquensis are reported to be altricial, but the level of development at birth is more advanced than that of T afra.
Differences in habitat and body size cannot account for the different life history styles of these four species. Congenerics of each species included in this study exhibit similar life-history styles, with the exception of Acomys species, and it is suggested that altriciality/precociality is a phylogenetically conservative character in small mammals.
... Various dermal glands are found in nearly all sengi taxa (Corbet and Hanks 1968;Faurie and Perrin 1995), but few are proportionately as large as that of M. micus. The subcaudal gland's function in M. micus is unknown; however, based on studies of other sengis, it likely produces scents used for intraspecific communication and structuring social interactions (Rathbun 1979(Rathbun , 2008Rathbun and Redford 1981;Koontz 1984;Koontz et al. 1999) that likely include monogamy. Social monogamy is characteristic of its congeners (Sauer 1973;Schubert et al. 2009) as well as several other sengis (Rathbun 1979;Rathbun and Rathbun 2006), and some type of social pairing was also suggested by our trapping results, especially considering the low densities that we encountered. ...
... The subcaudal gland's function in M. micus is unknown; however, based on studies of other sengis, it likely produces scents used for intraspecific communication and structuring social interactions (Rathbun 1979(Rathbun , 2008Rathbun and Redford 1981;Koontz 1984;Koontz et al. 1999) that likely include monogamy. Social monogamy is characteristic of its congeners (Sauer 1973;Schubert et al. 2009) as well as several other sengis (Rathbun 1979;Rathbun and Rathbun 2006), and some type of social pairing was also suggested by our trapping results, especially considering the low densities that we encountered. ...
While studying the systematics and taxonomy of round-eared sengis (genus Macroscelides), we identified an
unusual specimen from remote northwestern Namibia in the collection of the California Academy of Sciences.
To determine if this represented a different species, we made 9 collecting trips with 5,616 trap-nights of effort
that produced 16 voucher specimens (including the original specimen) of the unusual sengi. These specimens are
distinguished from other Macroscelides species by morphological metrics (they are smaller), external features
(rusty-tinged pelage, large subcaudal gland, and lack of dark skin pigment), and by divergence at 3 independently segregating DNA loci. These traits are the basis for the description of a new species of Macroscelides that seems to be confined to gravel plains associated with the distinctive reddish colored Etendeka
geological formation of northwestern Namibia. The new species appears to be reproductively isolated from
congeners, because portions of its distribution are sympatric with that of the Namib round-eared sengi (M.
flavicaudatus), and we found no evidence of hybrid individuals or gene flow. The new species is allopatric with
the Karoo round-eared sengi (M. proboscideus), which is found about 500 km to the south. The new species,
along with M. flavicaudatus, is endemic to Namibia. With this 3rd species in the genus, there are now 19
recognized extant species in the order Macroscelidea.
... On the basis mainly of a study of the golden-rumped sengi (Rhynchocyon chrysopygus) in coastal Kenya (Rathbun 1979), giant sengis are thought to be diurnal and monogamous. They construct nests of dead leaves on the forest floor in which they spend the night and give birth. ...
... They construct nests of dead leaves on the forest floor in which they spend the night and give birth. A large portion of their active time is spent foraging for invertebrates on the forest floor (Rathbun 1979). The paucity of data on the ecology of giant sengis stems from their shy nature combined with the difficulties of working in dense forests. ...
Three of the 4 species of giant sengis or elephant shrews (genus Rhynchocyon) have restricted geographic distributions in eastern Africa and are threatened by anthropogenic habitat loss. However, little is known about their ecology and habitat relationships. We used remotely triggered cameras to detect the gray-faced sengi (Rhynchocyon udzungwensis), which is endemic in the Udzungwa Mountains of Tanzania, with the aim of defining distributional limits, estimating occupancy patterns, and determining habitat requirements. We deployed 183 camera stations over 6 years and accumulated 4,600 camera trapping days. We refined the area of known occurrence to be 390 km 2 , thus confirming the species' restricted range and vulnerability. We estimated the average occupancy at 56% of sites occupied on sites sampled, and found that occupancy was best predicted by the forest habitat type, with interior, closed-canopy forest supporting highest estimated sengi occupancy. Terrain slope and distance to the nearest park boundary were less important covariates, but nevertheless included among the best models. Camera-trapping rate (photographic events by day) was significantly correlated with subcanopy tree coverage. Combined, these habitat features may provide optimal conditions for antipredation vigilance (vegetation cover), and for nest-building and/or foraging on invertebrates in the thicker leaf litter on gentle slopes. Our results offer new insights into the ecology of giant sengis and confirm the potential utility of camera trapping for occupancy analysis of small, forest-dwelling mammals.
... A 3rd group of behavioral hypotheses predicts that males gain enhanced fitness from pair-living by providing services that increase survival of females or reproduction. These services may include protection from predation (Kleiman and Malcolm 1981; trail maintenance in rufous sengis [Elephantulus rufescens] -Rathbun 1979;van Schaik and Dunbar 1990), protection from infanticide (Kappeler and van Schaik 2002;especially in primates-van Schaik and Kappeler 2003) and other forms of male aggression (Smuts and Smuts 1993), or foraging competition (Wittenberger and Tilson 1980). ...
... Variations on the protection from harassment by males or predation hypotheses predict that males provide indirect protection by maintaining escape routes or shelter sites (Kleiman and Malcolm 1981). For example, males of 2 sengi species, R. chrysopygus and E. rufescens, maintain multiple nests or extensive trail systems that are used by females for resting and traveling, respectively (Rathbun 1979). However, female T. tana nest separately from males in hollow logs or trees that have not been obviously manipulated (Emmons 2000). ...
Behavioral monogamy in mammals varies from male-female pairs that spend most of their time in close spatial contact (associated pair-living) to pairs that occupy exclusive territories but travel, forage, and sleep alone (dispersed pair-living). We present radiotelemetry data on 46 adult large treeshrews (Tupaia tana) from 2 populations in Sabah, Malaysia, that indicate that this species forms dispersed pairs across a range of ecological conditions. Dispersed pair-living was the primary behavioral mating system in primary forest during a major fruit masting event, in nonmasting primary forest, and in selectively logged forest with significantly higher fruitfall than in primary forest. Territories of behavioral partners were spatially concordant, but both male and female territories typically overlapped the boundaries of 1-3 extra-pair territories. Comparison between masting and nonmasting forests indicated that females exhibited better body condition during masting, whereas males exhibited larger home-range areas and longer daily movements. Both males and females exhibited better body condition in selectively logged versus primary forests, but ranging patterns were not significantly different between these habitats. We argue that intraspecific foraging competition is the most likely explanation for the evolution of dispersed pair-living in T. tana.
... Abarcan desde el extremo noroccidental (Fukuchani), hasta el límite suroriental (Maalum, en las proximidades de Paje, y Fumba en el entorno de Kiwani Bay). Lo que demuestra que el rango distributivo real de R. petersi adersi es mucho más extenso que el reconocido oficialmente (Hoffman et al., 2016), abarcando un mayor número de ubicaciones que conservan condiciones naturales compatibles con los requerimientos ecológicos de la especie (Rathbun, 1979). El sengi de Peters ha de ser puntualmente común en determinadas áreas ya que es bien conocido por los habitantes de la isla y se le atribuyen diferentes nombres locales. ...
Rhynchocyon petersi adersi es una subespecie de macroscélido endémica de los archipiélagos tanzanos de Zanzíbar y Mafia. Mientras que en la isla de Mafia la UICN determina una distribución generalizada, en la isla de Unguja su rango teórico se circunscribe al área centro-meridional. En este artículo se incorpora información corológica actualizada. Entre otros, se aportan nuevos datos que reflejan un rango distributivo mucho más amplio y acorde con la realidad. Con registros recientes en la mitad occidental de este espacio insular, donde estudios especializados argumentaban su ausencia.
... Although the mice and elephant-shrews that visit and pollinate the flowers of the four study species (Flasch et al. 2016;Wester et al. 2019Wester et al. , 2024Petra Wester, unpubl. data), are sensitive in the blue and green wavelengths (Jacobs et al. 2001;Thüs et al. 2020Thüs et al. , 2022, the animals are predominantly nocturnal or crepuscular (Rathbun 1979;Perrin 1981;Roxburgh and Perrin 1994;Stuart et al. 2003;Schumann et al. 2005;Skinner and Chimimba 2005;van der Merwe et al. 2012) or, if diurnal, their flower visiting behaviour happens also or predominantly at dusk or dawn (Melidonis and Peter 2015;Petra Wester, unpubl. data). ...
Background and aims – Fluorescence is the emission of light by a fluorophore that has absorbed light of shorter wavelengths. While the role of fluorescence in visual communication has been documented in some animals (budgerigars, gelatinous zooplankton), it is controversially discussed in plants. Floral nectar fluorescence has been mainly found in flowers pollinated by bees. It has been suggested as direct visual cue by which bees can evaluate the available quantity of nectar, thus being important for pollination and foraging efficiency. However, this function has been questioned, since fluorescence is said to be obscured by floral reflections due to low quantum efficiency. The aim of this study was to examine the nectar of plants pollinated by non-flying mammals, namely Eucomis regia, Massonia grandiflora, M. echinata, and M. pustulata (Asparagaceae) from South Africa.
Material and methods – To detect possible fluorescence in flowers, the plants were illuminated in a darkened room under UV light and photographed with a camera equipped with a UV/IR cut filter (transmitting at 400–700 nm).
Key results – Within the inflorescences, the nectar of all species showed blue to bluish fluorescence and UV absorption. Separated nectar also fluoresced.
Conclusion – As fluorescence in flowers occurs not only in bee-pollinated plants but also in plants pollinated by wind, and by nocturnal or crepuscular pollinators (non-flying mammals, bats, moths) for which floral scent is an important attractant, floral fluorescence seems to have no adaptive value for the attraction of flower visitors. We discuss the potential role of fluorescence in flowers as just a by-product of compounds that might have other functions such as visual attraction by reflection (or UV absorbance), protection of genetic material in pollen from UV induced damage, or as a floral filter causing nectar to be bitter, repelling ineffective pollinators but not effective ones.
... Solitary living in mammals is assumed to develop due to offspring dispersing when reaching adulthood either because they themselves develop the urge to leave, or because the mother rejects them. Maternal aggression towards offspring reaching puberty has been observed in European hamsters (Cricetus cricetus; Eibl-Eibesfeldt, 1953) and in some, but not all, species of elephant shrews (Rathbun, 1979;Schubert et al., 2012). More studies are needed to know how common maternal aggression is in inducing dispersal, or whether its internal motivation of the offspring when/after reaching puberty driving them to disperse and become solitary living. ...
While for decades behavioural ecologists have studied the costs and benefits of group living, solitary living has received little attention. Instead, it was assumed to be the default stage from which sociality evolved. Mammals underwent around 200 million years of social evolution, with a few species evolving communal or cooperative breeding in harsh environments. Other mammal species are successful with solitary living in exactly the same and many other environments, indicating that solitary living is beneficial under many environmental conditions. Comparative studies on mammals indicate that solitary living might not be the ancestral but a derived state. Solitary living in mammals is less common than previously believed, occurring in 22% of the studied species. Here, we review costs and benefits of solitary living in mammals. We found very few studies that considered solitary living and show important future avenues of research based on the factors that are important for the evolution of group living. We also emphasize that a solitary form of social organization does not imply an unsocial lifestyle: solitary mammals typically have non‐random but individualized social interactions with their neighbours, indicating important social structure.
... Il faut également .noter que certaines espèces se déplacent préférentiellement sur un réseau de pistes plus ou moins bien défini, comme le montrent notamment les travaux de O'Farrel (1965) Thomson (1982) sur le Rat des bois (Neotoma lepida), Rathbun (1979) sur la Musaraigne-éléphant (Rhynchocyon chrysopygus), Peters & Mech (1975) et Peters (1979) sur le Loup (Canis lupus), Pulliainen (1982) sur la Martre (Martes martes) et Jamon (1994) sur le Mulot sylvestre (Apodemus sylvaticus). Cela implique que l'utilisation de l'espace est dans ce cas plus ou moins restreinte à la structure dynamique du réseau des pistes. ...
Cet article propose une revue de question concernant le concept de domaine vital chez les mammifères terrestres. Les aspects sociaux liés à ce concept ne sont cependant pas abordés dans cet article qui se focalise essentiellement sur les aspects spatio-temporels et énergétiques. La relation empirique qu’on a pu établir entre la taille du domaine vital et les besoins énergétiques de l’animal y résidant, en fonction de ses caractéristiques spécifiques (masse corporelle, régime alimentaire) y est d’abord examinée. Une importance particulière est accordée à la distribution spatiale de l’activité sur le domaine vital, tant du point de vue empirique que de celui théorique des modèles qui ont été développés pour formaliser cette distribution. La distribution du marquage olfactif sur le domaine vital, et son rôle dans le maintien de la sédentarité sont également examinés. Le degré d’optimalité avec lequel un mammifère peut exploiter les ressources de son domaine vital est brièvement abordé dans le cadre de la théorie de l’approvisionnement optimal, dans la mesure où il apparaît que ce problème majeur est d’une trop grande complexité pour être formalisé de manière rigoureuse avec les modèles dont on dispose actuellement. Enfin, une dernière partie envisage en détail les mécanismes que les mammifères pourraient utiliser pour s’orienter dans leur domaine vital. En particulier, l’hypothèse populaire selon laquelle ce type d’orientation reposerait sur une carte cognitive globale du domaine vital est loin d’être prouvée, et une analyse parcimonieuse de la question indique qu’il n’est nullement nécessaire de recourir à une telle hypothèse.
... For example, elephant shrews (Elephantulus rufescens) restrict much of their travel to a network of trails from which they regularly remove plant material and other obstacles. It has been suggested that their rapid running along these trails is an effective anti-predatory strategy (Rankin, 1965;Rathbun, 1979). In larger animals, trails have been studied primarily in elephants (Loxodonta africana) (Vanleeuwe and Gautier-Hion, 1998;Mutinda et al., 2011) and mentioned in a few other studies (Di Fiore and Suarez, 2007;Noyce and Garshelis, 2014;Trapanese et al., 2019). ...
Cognition, defined as the processes concerned with the acquisition, retention and use of information, underlies animals’ abilities to navigate their local surroundings, embark on long-distance seasonal migrations, and socially learn information relevant to movement. Hence, in order to fully understand and predict animal movement, researchers must know the cognitive mechanisms that generate such movement. Work on a few model systems indicates that most animals possess excellent spatial learning and memory abilities, meaning that they can acquire and later recall information about distances and directions among relevant objects. Similarly, field work on several species has revealed some of the mechanisms that enable them to navigate over distances of up to several thousand kilometers. Key behaviors related to movement such as the choice of nest location, home range location and migration route are often affected by parents and other conspecifics. In some species, such social influence leads to the formation of aggregations, which in turn may lead to further social learning about food locations or other resources. Throughout the review, we note a variety of topics at the interface of cognition and movement that invite further investigation. These include the use of social information embedded in trails, the likely important roles of soundscapes and smellscapes, the mechanisms that large mammals rely on for long-distance migration, and the effects of expertise acquired over extended periods.
... Rhynchocyon ch. mandelai builds nests that appear similar to those of other giant sengis (Rathbun 1979;Andanje et al. 2010), consisting of a pile of leaf litter gathered in shallowly dug holes on the forest floor. A few nests were observed, and they occurred more frequently in areas with closed and high canopy with a thick leaf litter layer on the forest floor. ...
A new subspecies of giant sengi or elephant-shrew, first documented in 2008, is described from northern coastal Kenya. All five currently described species and most known subspecies of Rhynchocyon are compared to this new lineage. Molecular analyses using mitochondrial and nuclear markers from the single DNA sample available for the new lineage show differences from other forms and reveal a close relationship with the allopatric golden-rumped sengi R. chrysopygus (0.43% divergence at the 12S mitochondrial locus). This level of 12S divergence is similar to that between other subspecies pairs within Rhynchocyon. Based on three voucher specimens and 843 images from camera traps, the new lineage is similar to R. chrysopygus in the rufous-maroon sides and shoulders but is distinguished by the lack of the golden rump, the presence of jet-black distal rump and thighs, dark dorsal line, and a pronounced nuchal crest of hairs. Though it also shows superficial pelage similarities to two Tanzania species, R. udzungwensis and the dark coastal form of R. cirnei macrurus, the new form has differences in pelage coloration that are clearly diagnosable from all other taxa. This new lineage has an allopatric distribution to all known Rhynchocyon taxa, with the closest congener being R. chrysopygus located 140 km apart. We estimate a potential range size for the new taxon of ~1980 km2 in the Boni and Dodori National Reserves with habitat consisting of mixed thickets and dry forests. Because of its close genetic relationship with R. chrysopygus, its allopatric distribution, and divergent coloration, the new subspecies is designated Rhynchocyon chrysopygus mandelai. The previously described populations of R. chrysopygus from southern coastal Kenya are now designated R. chrysopygus chrysopygus. As the current severe political insecurity in the area threatens the new taxon, we hope that its description will help establish immediate conservation priorities and action for the subspecies and its habitat.
... Animals that maintain territories or home ranges and that liberate their attention from navigation by repeatedly following the same route are likely to make paths. Paths have numerous potential functions, including facilitating escape, orientation, and access to resources (Carroll & Getz, 1976;Paise & Vieira, 2006;Rathbun, 1979;Stamps, 1995). The F I G U R E 1 Paths, roads, and trails. ...
We assess the impacts of human paths, trails, and roads on plant species richness and Shannon diversity. Most reviews of this topic have not considered community‐level measures and have focused on excessive tourism impacts. We found significant positive effects of paths on plant richness and diversity. The effect size for richness was highest when studies included roads (paved) or trails (unpaved). The effect size found for diversity was highest when studies were in grasslands. We also found experimental designs comparing high levels of path use to low levels of path use, near‐to‐path versus far‐from‐path and path‐presence versus path‐absence comparisons obtained the largest effect sizes. There was no evidence that non‐native species explained most increases in species richness or diversity. The effect sizes of human paths on plant communities are comparable in magnitude to those reported for other mammals’ disturbance and ecosystem engineering activities.
... However, this is unlikely to affect our results because our sample is reflective of the overall variation in the species and because the values of CS are comparable between the 2 Macroscelides taxa. Secondary sexual dimorphism is not likely to be considerable because of the monogamous mating system proposed for these species (Rathbun 1979;Schubert et al. 2009). We adopted the same experimental design for shape in our evaluation of the relationship between size and geographic variation. ...
Sengis are small mammals in the order Macroscelidae that are shrew-like in appearance. They are cursorial and saltatorial, insectivorous and omnivorous. We studied Macroscelides spp. and Elephantulus rupestris with overlapping distributions in South Africa and Namibia. They have similar life histories and are good candidate species for comparative studies. We used geometric morphometric techniques for 3 views of a total of 43 skulls representing E. rupestris, M. flavicaudatus, and M. proboscideus to evaluate variation in skull shape that may be associated with geographical location. We pooled all Macroscelides into a single group because the speciation event was recent. We observed a pattern of shape variation in both taxa that followed a latitudinal gradient from the Western Province of Africa with Mediterranean vegetation to northern Namibia with xeric habitats. At higher latitudes, skulls were elongated with narrow frontals, premaxilla, and maxilla, while at low latitudes, the parietals were reduced and both occipitals and bullae timpanicae were expanded. We interpreted these patterns in the context of predator avoidance and foraging.
... The golden-rumped sengi (R. chrysopygus) is the only giant sengi whose behavioral ecology has been studied in sufficient detail to reveal that its life history is unusual for a small mammal (Rathbun, 2009). Individuals form monogamous pairs on territories, shelter singly in leaf nests on the forest floor, and produce one relatively precocial offspring at a time (FitzGibbon, 1997;Rathbun, 1979). ...
Giant sengis (Macroscelidea; Macroscelididae; Rhynchocyon), also known as giant elephant-shrews, are small-bodied mammals that range from central through eastern Africa. Previous research on giant sengi systematics has relied primarily on pelage color and geographic distribution. Because some species have complex phenotypic variation and large geographic ranges, we used molecular markers to evaluate the phylogeny and taxonomy of the genus, which currently includes four species: R. chrysopygus, R. cirnei (six subspecies), R. petersi (two subspecies), and R. udzungwensis. We extracted DNA from fresh and historical museum samples from all taxa except one R. cirnei subspecies, and we generated and analyzed approximately 4,700 aligned nucleotides (2,685 bases of mitochondrial DNA and 2,019 bases of nuclear DNA) to reconstruct a molecular phylogeny. We genetically evaluate Rhynchocyon spp. sequences previously published on GenBank, propose that the captive R. petersi population in North American zoos is likely R. p. adersi, and suggest that hybridization among taxa is not widespread in Rhynchocyon. The DNA sample we have from the distinctive but undescribed giant sengi from the Boni forest of northern coastal Kenya is unexpectedly nearly identical to R. chrysopygus, which will required further study. Our analyses support the current morphology-based taxonomy, with each recognized species forming a monophyletic clade, but we propose elevating R. c. stuhlmanni to a full species.
... This cranial overview can only be regarded as a first step toward a description of all sides of the Macroscelidean skull and a new attempt at a phylogenetic analysis of this order. The presence of the black-and-rufous sengi (Rhynchocyon petersi) in Diani coastal forest, Kenya, is well documented (Kingdon 1974, 1997, Rathbun 1979. However, the recent development of Diani Beach (near the village of Ukunda, south of Mombasa) as a popular holiday destination has led to some habitat transformation in the area. ...
... Eastern rock sengis, also known as elephant shrews, belong to the order Macroscelidaea that comprises 19 species (Dumbacher et al., 2014) that are endemic to Africa. All members of this order lack a sexual dimorphism, are considered monogamous with overlapping home ranges within pairs and rely on an insectivorous diet (Rathbun, 1979;FitzGibbon, 1997;Skinner and Chimimba, 2005;Rathbun and Rathbun, 2006;Schubert et al., 2009). A large diversity of ectoparasitic arthropods has been recorded for sengis mostly comprising ticks, fleas and mites, but also a single louse species (Neolinognathus elephantuli) (Fourie et al., 1995(Fourie et al., , 2002(Fourie et al., , 2005Segerman, 1995;Beaucournu et al., 2003;Harrison et al., 2011). ...
Concomitant infection with more than one parasite species is the rule in nature. Since co-infecting parasites are exploiting the same host, interspecific interaction at the infracommunity level is likely. The nature of such interactions can be expected to affect the distribution of parasites within host populations. Intraspecific interactions within the infracommunity are not easily discernible from cross-sectional studies and the focus of most of these studies lies on relationships between endoparasitic micro- and macroparasites. In the current study of the ectoparasite community of wild eastern rock sengis (Elephantulus myurus) we experimentally reduced tick and flea infestations and monitored ectoparasite burdens over the course of three years. We found a number of within-taxon facilitating interactions between tick species that might be the result of decreasing immune responses with increasing tick burden. In contrast, inter-taxon relationships appeared to be dominated by antagonistic relationships likely to be linked to competition over feeding sites. Only one of the observed interspecific interactions was reciprocal. Our experimental manipulation revealed additional antagonistic relationships that cross-sectional studies would not have captured. In addition, we found substantial long-term changes in the sengi ectoparasite community as a result of our experimental manipulation suggesting carry-over effects of our treatment. This study is the first that evaluates interspecific interactions within the entire ectoparasite community exploiting a mammalian host in Africa and highlights the complexity of interspecific interactions within an ectoparasite community.
... The physical isolation of Australia in the Tertiary is assumed to have slowed the arrival of large mammals (Flannery, 1989), and could have barred initial establishment of termite-and ant-eating forms. No termite-and ant-eating mammal save the striped possum is known from any island north of Australia from Sulawesi east of the Solomon Islands today (Whitten,TABLE 1. Termite-and ant-eating mammals in study areas (Me = Mediterranean, t-A = temperate-arid, s-A = subtropical-arid, Mo = monosonal) and elsewhere (N) in Australia and southern Africa, besides those shown in Fig. 2. Sources other than Rathbun (1979) for elephant shrews, and Kingdon (1974), Skinner & Smithers (1990) and Strahan (1993) for other species, are given in parentheses. ...
Myrmecophages (specialized termite- and ant-eating mammals) are smaller in Australia than in southern Africa, even where climate and soils are similar. For example, the pangolin in southern Africa (like the echidna in being toothless, armoured and slow in metabolism, movement and growth) is larger than any known Australian myrmecophage, living or extinct. This could be the result either of accidents of history or of different environments on the two continents. Four hypotheses which would support the historical explanation are refuted. There are no phylogenetic constraints on the incidents of large mammals in Australia, nor is there evidence that large myrmecophages have recently disappeared from our study areas. Evidence for myrmecophages larger than surviving forms occurring in the past is not greater in Australia than in southern Africa. Fungus-culturing termites (Macrotermitinae) are absent from Australia, but are eaten by the largest myrmecophage, the earth-pig, in southern Africa. Fungus-culturing and grass-eating termites are larger than their nearest counterparts in Australia. In semi-arid sample-sites with grasses and Acacia spp., termites are less abundant in Australia than in southern Africa. Large myrmecophages are associated with large leaf-eating eutherian mammals in southern Africa. We suggest that food consisting of termites and ants is less productive and reliable in Australia than in southern Africa. This may be partly because termites in Australia lack the relatively rich foods that are continually provided to their southern African counterparts by the trampling and dung of grazers and other herbivores and because sporadic but intense fires remove more foliage in Australia than in southern Africa. Our study refutes the role of chance in shaping the Australian fauna, and shows that different ecological conditions affect the biogeography of myrmecophages, and termites and ants eaten by them, on the two continents. The biotic, and possibly physical, environment is less favourable for large myrmecophages in Australia than in southern Africa.
... Various trapping methods have been used in the past in an attempt to capture elephant shrews alive. These methods included the use of bowstring snares (Brown 1964), long Table 2 Trapping statistics of small mammals captured at various localities in the 2926Aa quarter grid during the period February 1989 to May 1990 (See Table 1 nets and beaters (Van der Horst 1946;Brown 1964;Rankin 1965;Tripp 1972;Rathbun 1978Rathbun , 1979, drop traps (Rath bun 1979; Rathbun, Beaman & Maliniak 1981) and Sher man live traps (Tripp 1972;Neal 1982;Woodall & Mackie 1987;Woodall & Currie 1989). Various types of bait have also been used. ...
Species composition of prey consumed by spotted hyaenas Crocuta crocuta in three divergent areas in southern Africa was determined by scat analyses. The larger abundant antelopes predominated in the diet and their occurrence in the diet was apparently directly related to the availability of the prey within the hyaena foraging areas. In Mkuzi' Game Reserve and the Namib Naukluft National Park, hyaenas coexist with only one other large predator. In Umfolozi Game Reserve, where hyaenas coexist with four other large predators, a greater variety of prey was taken. Scat weight in desert-dwelling hyaenas was twice that of those from more mesic areas, which may be an adaptation to restricted water intake. The incidence of domestic livestock in the diet was meagre, probably the result of collecting scats only from latrines within the game reserves. Die spesies-samestelling van prooi verbruik deur gevlekte hienas Crocuta crocuta in drie verskillende gebiede in Suidelike Afrika is bepaal deur faeces-analise. Die groter meer volop wildsbokke het die dieet gedomineer en die voorkoms in dieet toon 'n direkte verwantskap met beskik baarheid van prooi in hiena-jaggebiede. Hienas deel Mkuzi Wildtuin en die Namib Naukluft Nasionale Park met slegs een ander groot roofdier terwyl vier ander groot roofdiere Umfolozi Wildtuin met hienas deel, wat lei tot groter variasie in prooi-items. Faeces-massa van woestynlewende hienas ..,as twee keer meer as die van hienas in meer mesiese gebiede wat waarskynlik 'n aanpassing is vir beperkte water inname. Die voorkoms van plaasdiere in die dieet was baie laag, maar dit is heel waarskynlik as gevolg van faeces versameling slegs binne die wildtuine.
... More recently, Nistri and Vanni (2014, personal communication) found no evidence of sengis in Djibouti during their expedition, and we (PA, unpublished data) similarly found none during a 2013 small mammal collecting trip to Djibouti. Although it is possible that sengis have escaped detection in Djibouti, this seems increasingly unlikely given that they are relatively easy to trap (Rathbun & Rathbun 2006), and they are not difficult to see by keen observers during the day, or at dawn and dusk (Rathbun 1979). We hope that this account will result in a greater effort to resolve this issue, especially given that Elephantulus in Djibouti would likely represent the furthest northern occurrence, south of the Sahara Desert (Rathbun 2014). ...
Sengi or elephant-shrew specimens in the Zoological Section of the Natural History Museum, Florence University, increase the known distribution of the endemic Somali sengi (Elephantulus revoilii) by 475 km. The expanded range may improve its conservation status, but the information raises questions on habitat and taxonomic separation from the closely related sympatric E. rufescens.
... It is very fast…. ' The limbs and other unique characteristics of elephant-shrews (exposed shelter sites, mixed herbivory and insectivory, social monogamy, small precocial litters and small body size <1 kg), have been described as 'the micro-cursorial adaptive syndrome' (Rathbun, 1979;Rathbun, 2009). ...
In this study we report on the evolution of micro-cursoriality, a unique case of cursoriality in mammals smaller than 1 kg. We obtained new running speed and limb morphology data for two species of elephant-shrews (Elephantulus spp., Macroscelidae) from Namaqualand, South Africa, which we compared with published data for other mammals. Elephantulus maximum running speeds were higher than most mammals smaller than 1 kg. Elephantulus also possess exceptionally high metatarsal:femur ratios (1.07) that are typically associated with fast unguligrade cursors. Cursoriality evolved in the Artiodactyla, Perissodactyla, and Carnivora coincident with global cooling and the replacement of forests with open landscapes in the Oligocene and Miocene. The majority of mammal species, though, remained non-cursorial, plantigrade, and small (< 1 kg). The extraordinary running speed and digitigrady of elephant-shrews was established in the Early Eocene in the earliest macroscelid Prodiacodon, but was probably inherited from Paleocene, Holarctic stem macroscelids. Micro-cursoriality in macroscelids evolved from the plesiomorphic plantigrade foot of the possum-like ancestral mammal earlier than in other mammalian crown groups. Micro-cursoriality evolved first in forests, presumably in response to selection for rapid running speeds facilitated by local knowledge, in order to avoid predators. During the Miocene, micro-cursoriality was pre-adaptive to open, arid habitats, and became more derived in the newly-evolved Elephantulus and Macroscelides elephant-shrews with trail running.
... Elephant-shrews (also called sengis) are small-bodied, capable of rapid movement (jumping and running), and insectivorous. They display social monogamy (Rathbun 1979). Two extant subfamilies, the Macroscelidinae and Rhynchocyoninae, are recognized within the order. ...
Elephant-shrews (also called sengis, order Macroscelidea) are small-bodied insectivorous mammals with a strictly African distribution. Fifteen species currently are recognized, of which 9 occur in the southern African subregion. On the basis of molecular, cytogenetic, and morphological evidence, Elephantulus edwardii, the only strictly South African endemic species, is shown to comprise 2 closely related taxa. The new Elephantulus taxon described herein is from the central Nama-Karoo region of Western Cape and Northern Cape Provinces. Important genetic distinctions underpin its delimitation. Sequence data from the mitochondrial cytochrome-b gene and the hypervariable control region as well as 7th intron of the nuclear fibrinogen gene show these 2 taxa to be reciprocally monophyletic. They are separated by 13.8% sequence divergence (uncorrected) based on the 2 mitochondrial segments, and 4.2% based on the nuclear intron sequences. In addition, fixed cytogenetic differences include a centromeric shift, heterochromatic differences on autosomal pairs 1–6, and the number of nucleolar organizer regions. The new species has several subtle morphological and phenotypic characters that distinguish it from its sibling species E. edwardii, the most striking of which is the presence of a tail-tuft, as well as the color of the flanks and the ventral pelage. The abundance, detailed distribution of the new form, and its life-history characteristics are not known, and further studies clearly are needed to determine its conservation status.
Bércouni (řád Macroscelidea) představují nepočetný řád savců, který vyniká mnoha jedinečnými vlastnostmi. Jejich název poukazuje na prodloužené zadní končetiny, které jim při běhu umožňují dosáhnout skutečně nevídané rychlosti. Celá řada zajímavostí se pak pojí srozmnožováním a vývojem mláďat,
která se rodí vysoce prekociální. O pokročilé vyvinutosti novorozených bércounů jsme se nedávno přesvědčili při prvním odchovu bércouna afrického (Macroscelides proboscideus) v Zoo Praha. Cílem tohoto
příspěvku je podělit se o zkušenosti získané tímto odchovem a zasadit je do širšího kontextu dosavadních poznatků o rozmnožování a postnatálním vývoji bércounů.
Beside insects, sengis also consume plant material such as leaves, fruits, seeds and floral nectar. It is known that they use olfaction for foraging, but little is known about their vision and visual learning capabilities. Colour vision has been tested in two species, showing that they are likely dichromats (green- and blue-sensitive retinal cone-photoreceptors, meaning red-green colour blind). Our aim was to examine the learning and colour discrimination abilities of another species, Elephantulus edwardii . Using training procedures and choice experiments, we tested the hypotheses that the animals can associate a reward with trained colours and that they can discriminate between different colour hues. The sengis preferred the trained colours over the others, indicating associative learning. They could discriminate between all tested colours (blue, red, green, yellow). The sengis’ colour choice behaviour indicates that the animals can use also colour features to find food plant material. Additionally, learning abilities most likely are essential for the sengis’ foraging activities, for instance by associating floral or fruit shape, colour or scent with nectar or ripe fruit, to increase the efficiency to locate food sources.
Of the eighteen sub‐Saharan elephant‐shrew species, only eastern rock elephant‐shrews reproduce seasonally throughout their distribution, a process seemingly independent of photoperiod. The present study characterizes gonadal status and location/intensity of GnRH‐1 and kisspeptin immunoreactivities in this polyovulating species in the breeding and non‐breeding seasons. GnRH‐1‐immunoreactive (ir) cell bodies are predominantly in the medial septum, diagonal band and medial preoptic area; processes are generally sparse except in the external median eminence. Kisspeptin‐ir cell bodies are detected only within the arcuate nucleus; the density of processes is generally low, except in the septohypothalamic nucleus, ventromedial bed nucleus of the stria terminalis, arcuate nucleus and internal and external median eminence. Kisspeptin‐ir processes are negligible at locations containing GnRH‐1‐ir cell bodies. The external median eminence is the only site with conspicuously overlapping distributions of the respective immunoreactivities and, accordingly, a putative site for kisspeptin's regulation of GnRH‐1 release in this species. In the non‐breeding season in males, there is an increase in the rostral population of GnRH‐1‐ir cell bodies and density of GnRH‐1‐ir processes in the median eminence. In both sexes, the breeding season is associated with increased kisspeptin‐ir process density in the rostral periventricular area of the third ventricle and arcuate nucleus; at the latter site this is positively correlated with gonadal mass. Cross‐species comparisons lead us to hypothesize differential mechanisms within these peptidergic systems: that increased GnRH‐1 immunoreactivity during the non‐breeding season reflects increased accumulation with reduced release; that increased kisspeptin immunoreactivity during the breeding season reflects increased synthesis with increased release.
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Many mammals, ranging from antelope to elephant shrews, eat ants and termites. The specialized mammalian myrmecophages (ant- and termite-eaters) such as aardvarks and pangolins have long drawn attention, but little work has been done on general predator-prey relationships between mammals and ants and termites.
Among ungulates, monogamy is generally said to have evolved in a small number of species inhabiting forests or thickets (Estes, 1974; Geist, 1974; Jarman, 1974; Leuthold, 1977). In such habitats, these species have adapted to selective browsing, and their food habits have resulted in spacing, territoriality, solitary living, or living as single male-female pairs (Jarman, 1974). In those species where pair members spend comparatively long periods of time together, such as Kirk's dik-dik (Madoqua kirkii: Hendrichs&Hendrichs, 1971; Hendrichs, 1975; Tilson&Tilson, 1986; Brotherton&Rhodes, 1996; Komers, 1996; Brotherton&Manser, 1997), and the klipspringer (Oreotragus oreotragus: Dunbar&Dunbar, 1980), social monogamy has been well documented. Genetic monogamy has also been proven in Kirk's dik-dik, (Brotherton et al., 1997). However, because interactions between males and females are very rare, it has not yet been demonstrated that solitary ungulates are socially monogamous. If in fact they are socially monogamous, why do they exhibit this type of monogamy, and how do they maintain the pair bond? Asolitary ungulate, the Japanese serow (Capricornis crispus) is a good species to use as a case study to answer these questions. The recent increase in the population of Japanese serows, which has been strictly protected in Japan since 1955, now facilitates behavioural observation in the field.
One of the most bizarre groups to turn up in the zoological literature is the mammalian order Rhinogradentia (Stümpke 1967, published posthumously). This group of 150 outrageously endowed species—informally known as snouters—was apparently confined to the obscure South Sea islands of Hi-yi-yi. I say “was” in the acknowledgment that, quite tragically (and conveniently?), snouters, islands, and Stümpke were erased in a nuclear test accident two decades ago.
L.D. 2012. New large leptictid insectivore from the Late Paleogene of South Dakota, USA. Acta Palaeontologica Polonica 57 (3): 509–518. From a skull and mandible, we describe a new genus and species of a primitive insectivore (Mammalia: Insectivora: Leptictida: Leptictidae). Its large body size and higher−crowned teeth indicate a different feeding ecology from other leptictid insectivores. With evidence of some heavy, flat wear on the molariform teeth, its shift in diet was likely to greater herbivory. Unlike the narrow snout of Blacktops, this new leptictid retains a broad snout, suggesting that small verte− brates were still important dietary components. The specimen was collected from the floodplain deposits of the lower or middle White River Group of South Dakota, which represent the latest Eocene to earliest Oligocene (Chadronian and Orellan North American Land Mammal "Ages").
We investigated locomotor activity rhythms in the little‐studied wild‐caught eastern rock sengi (Elephantulus myurus) from Goro Game Reserve, Limpopo Province, South Africa. To assess whether locomotor activity is endogenously entrained by the light–dark cycle, animals (n = 13) were subjected to three different light‐cycle regimes: a 12 h light/12 h darkness (LD) cycle, a total darkness (DD) cycle and an inverse of the LD cycle (DL). Ten animals exhibited strong light entrainment under LD1 with the total percentage of activity during the light phase (56.5% ± 11.9%) significantly higher than during the dark phase (43.5% ± 11.9%). Eleven animals expressed distinct endogenous free‐running rhythms under DD (mean τ = 23.6 h ± 0.6 h; range: 22.9 h–24.5 h), with significant inter‐individual variation. Under DL, the total percentage of activity was approximately equal during the light (50.4% ± 7.8%) and dark phase (49.6% ± 7.8%). E. myurus was on average active 25% of the 24‐h day with a nocturnal–diurnal ratio of 0.8 under LD1 and exhibited locomotor activity under controlled conditions similar to that of closely related species in the wild. In 62% of the animals, activity was highest around dawn, lowest during the afternoon and intermittently expressed throughout the night. Little quantitative data are available on the daily locomotor activity rhythms of sengis particularly in response to the light–dark cycle. This study provides valuable quantitative data on locomotor activity rhythms in E. myurus.
Throughout the Cenozoic, the fitness benefits of the scrotum in placental mammals presumably outweighed the fitness costs through damage, yet a definitive hypothesis for its evolution remains elusive. Here, I present an hypothesis (Endothermic Pulses Hypothesis) which argues that the evolution of the scrotum was driven by Cenozoic pulses in endothermy, that is, increases in normothermic body temperature, which occurred in Boreotheria (rodents, primates, lagomorphs, carnivores, bats, lipotyphylans and ungulates) in response to factors such as cursoriality and climate adaptation. The model argues that stabilizing selection maintained an optimum temperature for spermatogenesis and sperm storage throughout the Cenozoic at the lower plesiomorphic levels of body temperature that prevailed in ancestral mammals for at least 163 million years. Evolutionary stasis may have been driven by reduced rates of germ-cell mutations at lower body temperatures. Following the extinction of the dinosaurs at the Cretaceous–Palaeogene boundary 65.5 mya, immediate pulses in endothermy occurred associated with the dramatic radiation of the modern placental mammal orders. The fitness advantages of an optimum temperature of spermatogenesis outweighed the potential costs of testes externalization and paved the way for the evolution of the scrotum. The scrotum evolved within several hundred thousand years of the K-Pg extinction, probably associated initially with the evolution of cursoriality, and arguably facilitated mid- and late Cenozoic metabolic adaptations to factors such as climate, flight in bats and sociality in primates.
The rufous elephant-shrew (Elephantulus rufescens), a monomorphic species found in the dry bushlands of East Africa, possesses a sternal gland that is used in scent marking. We examined the anatomy and maturation of the sternal gland of captive E. rufescens, and we identified some of the volatile compounds it secretes. Histological observations reveal that the gland contains primarily sebaceous components, but apocrine components also are observed. The sternal gland begins secreting at approximately 5.4 weeks of age, when E. rufescens begins to exhibit other adult features. Glands are larger in males than females, despite the fact that females are dominant. Gland activity was greatest in heterosexually paired males, and did not vary seasonally. Gas chromatograms indicate more than 100 components in the secretions of adult males and females. Thirty-seven compounds, including four hydrocarbons, 10 fatty acids, 14 esters, four alcohols, one sterol, one aldehyde, one ketone, one amine, and one nitrile, were tentatively identified by mass spectra.
An amazing variety of animals communicate by vibrational signals. The behavior is common, diverse and occurs in multiple taxa ranging from spiders and insects to rodents and elephants. Production of vibrations is a mechanical event of stomping, tapping, drumming, rubbing surfaces together (stridulation) and trem-bling the body (trembulation) to transmit both airborne and seismic signals. Ground-borne vibrations are transmit through a diversity of substrates, including soil, rocks, leaf litter and plant stems and leaves. Receptors for the signals consist of ears and mechanoreceptors in mammals and specialized structures in arthropods. Mate attraction is an important function of substrate-borne vibrations, which are often combined with visual displays in multimodal courtship displays. In spiders substrate-borne vibrations function as sexually selected signals of fi tness. Besides attracting mates, insects use vibrations to communicate between parent and offspring, members of the social group, food recruitment and in predator defense. Substrate-borne vibrations also are important in predator–prey interactions. Footdrumming as a communication system is the most developed in territorial kangaroo rats (Dipodomys). The species specifi c drumming patterns can be complex, and the bannertailed kangaroo rat (D. spectabilis) drums individually distinct footdrumming signatures to communicate territorial ownership. Kangaroo rats also drum during competitive interactions and courtship. In the presence of snakes the kangaroo rats footdrum in individual defense to inform the snake the kangaroo rat is aware and will no longer be easy prey.
We studied maternal, paternal, and alloparental care in striped mice (Rhabdomys pumilio), which nest and breed communally in the succulent karoo, South Africa. A total of 18 triads, each consisting of 2 adult female littermates and an unfamiliar adult male, were set up under natural weather conditions. We expected that relationships within captive triads that breed communally would be egalitarian, and that all individuals would participate in the rearing of offspring, but we assumed that the degree of caregiving behavior would vary between mothers, fathers, and alloparents, because individuals obtain different fitness benefits. Social interactions in the triads were predominantly amicable and in the majority of triads, both females produced litters in a communal nest. All 3 adults in a triad participated in care of the offspring, with mothers spending 43%, fathers 26%, and alloparents 24% of observations in caregiving activities. Our results indicate that sisters can for
m stable cooperative relationships, but members of a communal nest allocate their caregiving to individual offspring according to potential trade-offs between direct and indirect fitness benefits. Large amounts of paternal care can occur in a polygynous species, which contrasts with the common belief that paternal care is a characteristic of monogamy.
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