ArticlePDF Available

Golden hamsters are nocturnal in captivity but diurnal in nature


Abstract and Figures

Daily activity rhythms are nearly universal among animals and their specific pattern is an adaptation of each species to its ecological niche. Owing to the extremely consistent nocturnal patterns of activity shown by golden hamsters (Mesocricetus auratus) in the laboratory, this species is a prime model for studying the mechanisms controlling circadian rhythms. In contrast to laboratory data, we discovered that female hamsters in the wild were almost exclusively diurnal. These results raise many questions about the ecological variables that shape the activity patterns in golden hamsters and the differences between laboratory and field results.
Content may be subject to copyright.
Biol. Lett. (2008) 4, 253–255
Published online 8 April 2008
Animal behaviour
Golden hamsters are
nocturnal in captivity but
diurnal in nature
Rolf Gattermann
, Robert E. Johnston
Nuri Yigit
, Peter Fritzsche
, Samantha Larimer
Sakir O
, Karsten Neumann
, Zhimin Song
ment Colak
, Joan Johnston
and M. Elsbeth McPhee
Institute of Zoology, Martin-Luther University, Halle-Wittenberg,
Domplatz 4, 06108 Halle (Saale), Germany
Department of Psychology, Cornell University, Ithaca,
NY 14853, USA
Department of Biology, University of Ankara, 06100 Ankara, Turkey
Department of Biology, Gazi University, 06500 Ankara, Turkey
*Author for correspondence (
Daily activity rhythms are nearly universal
among animals and their specific pattern is an
adaptation of each species to its ecological niche.
Owing to the extremely consistent nocturnal
patterns of activity shown by golden hamsters
(Mesocricetus auratus) in the laboratory, this
species is a prime model for studying the
mechanisms controlling circadian rhythms. In
contrast to laboratory data, we discove red that
female hamsters in the wild were almost
exclusively diurnal. These results raise many
questions about the ecological variables that shape
the activity patterns in golden hamsters and the
differenc es between laboratory a nd field results.
Keywords: activity rhythms; field study;
Mesocricetus auratus
Virtually all living organisms show periodic rhythms
in activity and physiological processes. Most of these
rhythms have a roughly 24-hour periodicity and are
synchronized with the daily light cycle, resulting in
species-typical activity patterns (e.g. diurnal, noctur-
nal and crepuscular). Discoveries characterizing the
timing of these rhythms, the biochemical and neural
mechanisms involved and the mechanisms by which
these patterns are entrained by environmental cues
represent major achievements in science (Aschoff
1965; Pittendrigh 1993; Dunlap et al. 2004). In
mammals, these behavioural and physiological
rhythms are synchronized within an individual by
pacemaker cells in the suprachiasmatic nucleus
(SCN) of the brain. The length and pattern of activity
are generally stereotyped for each species but differ
between species, suggesting that the timing of activity
is adaptive (Sharma 2003).
In contrast to the literature describing the
mechanisms underlying activity patterns, the influ-
ence of extrinsic ecological variables on these patterns
has been less thoroughly studied and is not well
understood (Enright 1970; Halle 2000)—primarily
owing to the difficulties associated with identifying
and quantifying the many factors that influence
activity patterns (DeCoursey et al. 2000). Several
studies have documented shifts in activity in response
to predator risk. Fenn & Macdonald (1995) observed
diurnal activity in normally nocturnal wild rats
(Rattus norvegicus) and found that the rats were active
during the day to avoid predation by nocturnal foxes
(Vulpes vulpes). Coyotes (Canis latrans) exposed to
human persecution during the day were largely
nocturnal, but when persecution ceased they exhib-
ited more diurnal patterns of activity (Kitchen et al.
2000). Comparing a group of free-living, SCN-
lesioned eastern chipmunks (Tamias striatus)with
sham-lesioned and intact control chipmunks,
DeCoursey et al. (2000) found that the SCN-lesioned
group experienced significantly higher levels of
predator-induced mortality than the other groups,
presumably due to inappropriate activity cycles.
One of the primary mammalian species used in
research on activity rhythms and their underlying
mechanisms is the golden hamster (Mesocr icetus
auratus). Hamsters are important because they are
strictly nocturnal in the laboratory and show a
remarkable consistency in the timing of their rhythms.
More than 80% of laboratory hamster activity occurs
at night, regardless of the testing environment or the
measure of activity (Pratt&Goldman1986a,b).
Typically, activity peaks shortly after the onset of dark
followed by a gradual decline throughout the night
(Gattermann 1984; Fritzsche 1987; figure 1). Indi-
viduals that are shifted from a light–dark cycle to
complete darkness maintain their normal activity
pattern and a regular period length. The period
length can also be changed by altering the light cycle,
as would occur in animals living in the wild in
different seasons (Pittendrigh & Minis 1964).
Despite being a common model species in biologi-
cal research, little is known about golden hamsters in
the wild. In addition, the laboratory hamsters are
descendents of a brother–sister pair mated in 1930
(Aharoni 1932; Murphy 1971; Gattermann et al.
2001). Given this, we established a research pro-
gramme in southern Turkey to study hamsters in
their native habitat. Our study represents the first
time that the behaviour and activity patterns of
golden hamsters have been recorded in the wild.
(a) Laboratory populations
For comparing with the wild populations, we measured the activity
patterns of hamsters in the Gatterman Laboratory at Martin-
Luther-University, Halle-Wittenberg, Germany. The activity was
measured for 21 days on 10 female golden hamsters. The study
population was derived from 23 animals captured in Syria and
southern Turkey in 1999; the captive animals were roughly five
generations removed from their wild progenitors. The animals were
8 to 10 months old and housed in temperature-controlled rooms
(ambient temperature, 22G28C; relative humidity, 55–65%). They
were exposed to an artificial light–dark cycle of 12 L : 12 D hours
with lights on from 07.00 to 19.00 Central European Time. The
average light intensities during the dark phase were nearly 0 lx, and
those during the light phase were 200 lx. This difference between
the dark and light phases is sufficient for entrainment to the light
cycle. The animals were kept solitarily in macrolon cages (54!
33!20 cm). To simulate a burrow, the cage was equipped with a
sleeping chamber, an opaque plastic cylinder (18 cm in length and
The authors dedicate this manuscript to Rolf Gattermann who died
from cancer in 2006.
Received 4 February 2008
Accepted 19 March 2008
253 This journal is q 2008 The Royal Society
10 cm in diameter) that was closed on both ends; at one end was a
5 cm diameter entrance. Standardized food (Altromin) and drink-
ing water were available ad libitum.
The locomotor activity outside the sleeping box was monitored
continuously using a passive infrared detector. A single beam ran
through the centre of the cage and the activity was counted as the
number of times the beam was broken; the activity counts were
recorded using the Chronobiology Kit (Stanford Software Systems,
Santa Cruz, CA, USA). As with the field data, these data were used
to calculate the number of minutes per hour an animal was active.
(b) Wild populations
In the wild, golden hamsters are solitary, widely dispersed and do
not engage in much social activity. We observed the behaviour and
daily activity patterns for 12 female hamsters in southern Turkey
for 9–28 days during April and May 2005 and 2006. The
temperature in April ranged from 5 to 258C and in May from 6 to
368C. The mean temperature for 2005 and 2006 was 17G1.28C
and 18G1.68C, respectively. On a sunny day, the light intensities
could reach 100 000 lx.
To record activity, an individually coded passive integrated
transponder ( PIT) tag was injected subcutaneously into each
individual. Burrow entrances of occupied burrows were fitted with
a plastic ring containing a PIT tag reader that recorded which
individuals were moving in and out of the burrow. The rings also
projected two infrared beams, one above the other, across the
burrow entrance; the sequence of the beam interruption indicated
whether the animal was entering or exiting the burrow. These data
were recorded and used to calculate the number of minutes per
hour the animal was out of the burrow.
(a) Activity in the laboratory
The activity patterns for the laboratory population
were sharply nocturnal, with activity peaking at the
start of the dark period; virtually no activity occurred
when lights were on (figure 1a). The amount of
activity varied across the females’ 4-day oestrous
cycle, but there were no differences in the onset of
activity across the cycle and thus no differences in the
overall activity pattern.
(b) Activity in nature
In the wild, female golden hamsters were out of their
burrows almost exclusively during daylight hours
(figure 1b). There were two periods of activity:
between 06.00 and 08.00 and 16.00 and 19.30.
Almost no activity occurred during the middle of the
day (10.00–16.00) or at night (after 20.00 hours).
The average total time spent in surface activity over
24 hours was 87 min; almost all of this time was
spent foraging. The overall patterns did not change
with temperature.
While all females were active during the morning
and afternoon periods, there were differences in the
onset of timing of activity across individuals. Some
females displayed more activity in the morning, while
others preferred the afternoon; one female tended to
start and end her activity later in the morning than
any of the others. Sometimes a female skipped a
morning or afternoon period of activity. However, we
do not know how much or when the females were
active inside their burrow. Attempts to obtain these
data were unsuccessful due to technical problems.
These findings for females differ from all reports on
this species in captivity, both in the timing and the
total duration of activity, including studies in which
the animals lived in burrows (Pratt & Goldman
1986a). Although bimodal circadian rhythms have
been produced in captivity under special lighting
conditions (Shibuya et al. 1980), these patterns are
quite different from the regular bimodal patterns we
observed in nature.
The activity patterns we observed cannot necess-
arily be attributed to genetic changes in laboratory
strains. The patterns shown by the fifth generation
wild-type stock tested in Germany are not different
from similar data collected from domestic stock tested
at Cornell University (Larimer 2007). In addition, 10
wild-caught male hamsters were observed in captivity
in Germany four weeks after their capture and
transfer to standard laboratory conditions. Although
these hamsters showed the strictly nocturnal pattern
shown in figure 1a, males in the wild show activity
throughout the 24-hour period ( R. E. Johnston 2005,
2006, unpublished data; Weinert et al. 2001).
What factors account for differences between
activity patterns in nature and in captivity? Levy et al.
(2007) foundthatlaboratorygoldenspinymice
(Acomys russatus) are nocturnal while wild mice are
diurnal. They suggested that environmental cues in
the field mask internal rhythms, resulting in activity
patterns that differ between the field and laboratory
(Levy et al. 2007).
A variety of factors are known to influence (or
mask) activity rhythms, including predation, tempera-
ture, humidity, rainfall and food availability (for a
discussion of masking, see Mrosovsky (1999) and
Dunlap et al. (2004)). We propose that the diurnal
12.00 16.00 20.00 24.00
time of da
4.00 8.00 12.00
activity (%)activity (%)
Figure 1. Percentage of time active per hour during a
24-hour period: data collected in (a) the German laboratory
and (b) the field (Turkey). The bars are 95% CIs; the dark
period is indicated by the black bar above the graph and the
grey bar indicates dawn and dusk.
254 R. Gattermann et al. Field versus laboratory activity
Biol. Lett. (2008)
mechanism to avoid nocturnal predators. Owl
(Tylo alba, Athene noctua) pellets collected around our
field site contained hamster teeth, while fox (V. vulpes)
were observed in the area at dawn and dusk and feral
dogs were observed at all times. Potential diurnal
predators include migrating and resident raptors (e.g.
Buteo rufinus, Circus pygargus, Falco tinnunculus) and
white storks (Ciconia ciconia) but all of these were
rare. A number of snakes were recorded in the general
area (e.g. Vipera lebetina, Coluber jugularis, Spalerosophis
diadema) but none were seen around hamster burrows.
In addition, we suggest that hamsters in the field
constrain their activity to avoid high mid-day surface
temperatures. The short duration of the daily activity
suggests that females balance foraging needs, predator
avoidance and potential heat stress.
Our observations indicate that the control of
activity rhythms in hamsters is much more complex
and more sensitive to environmental factors than
previously realized, thus suggesting new questions for
investigation. We do not know how hamster activity
patterns vary throughout the year, but our findings
raise the question of whether the activity patterns
described in laboratories ever occur in nature. To
obtain a thorough understanding of biological
rhythms and their plasticity, we must expand the
range of experiments carried out in captivity and
conduct more research in natural and laboratory
settings (Smale et al. 2003).
This work was supported by NSF grant NSF/IBN-0318073
to R.E.J. and a TUBITAK grant to R.E.J., N.Y. and S.O. We
are indebted to Safak Bulut and Ferhat Matur for their
practical help in the field, serving as translators, obtaining
permits and facilitating communication with citizens of Elbeyli
and local officials. Cumali Ozcan provided valuable help in
the field and with community relationships. Fulya Saygili and
Duygu Yuce also provided occasional help in the field.
Aharoni, B. 1932 Die Muriden von Pala¨stina und Syrien. Z.
ugetierkd. 7, 166 –240.
Aschoff, J. (ed.) 1965 Circadian clocks. Amsterdam, The
Netherlands: North-Holland
DeCoursey, P. J., Walker, J. K. & Smith, S. A. 2000 A
circadian pacemaker in free-living chipmunks: essential
for survival? J. Comp. Physiol. A 186, 169–180. (doi:10.
Dunlap, J., Loros, J. & DeCoursey, P. J. (eds) 2004
Chronobiology: biological timekeeping. Sunderland, MA:
Sinauer Associates, Inc.
Enright, J. T. 1970 Ecological aspects of endogenous
rhythmicity. Annu. Rev. Ecol. Syst. 1, 221–238. (doi:10.
Fenn, M. G. P. & Macdonald, D. W. 1995 Use of middens
by red foxes: risk reverses rhythms of rats. J. Mammal.
76, 130–136. (doi:10.2307/1382321)
Fritzsche, P. 1987 Zur Infradianrhythmik (Circaquadri-
dianrhythmik) des Goldhamsters (Mesocricetus auratus
Waterhouse 1839). Zool. Jahrb. Physiol. 91, 403 418.
Gattermann, R. 1984 Zur Biorhymik des Goldhamsters.
Zirkadiane Rhythmen. Zool. 88, 471– 489.
Gattermann, R., Fritzsche, P., Neumann, K., Al-Hussein,
I., Kayser, A., Abiad, M. & Yakti, R. 2001 Notes on the
current distribution and the ecology of wild golden
hamsters (Mesocricetus auratus). J. Zool. 254, 359 365.
Halle, S. 2000 Ecological relevance of daily activity
patterns. In Ecological studies: Activity patterns in small
mammals, an ecological approach, vol. 141 (eds S. Halle &
N. C. Stenseth), pp. 67–90. New York, NY: Springer.
in coyote activity patterns due to reduced exposure to
human persecution. Canad. J. Zool. 78, 853–857. (doi:10.
Larimer, S. 2007 Golden hamsters, Mesocricetus auratus,as
a model species for studying circadian rhythms and
olfactory memory: studies in the lab and in nature. PhD
thesis, Cornell University, Ithica.
Levy, O., Dayan, T. & Kronfeld-Schor, N. 2007 The
relationship between the golden spiny mouse circadian
system and its diurnal activity: an experimental field
enclosures and laboratory study. Chronobiol. Int. 24,
599–613. (doi:10.1080/07420520701534640)
Mrosovsky, N. 1999 Masking: history, definitions, and
measurements. Chronobiol. Int. 16, 415 429. (doi:10.
Murphy, M. R. 1971 Natural history of the Syrian golden
hamster—a reconnaissance expedition. Am. Soc. Zool.
11, 632.
Pittendrigh, C. S. 1993 Temporal organization: reflections
of a Darwinian clock-watcher. Annu. Rev. Physiol. 55,
17–54. (doi:10.1146/
Pittendrigh, C. S. & Minis, D. H. 1964 The entrainment of
circadian oscillations by light and their role as photoperiodic
clocks. Am. Nat. 98,261294.(doi:10.1086/282327)
Pratt, B. L. & Goldman, B. D. 1986a Activity rhythms and
photoperiodism of Syrian hamsters in a simulated
burrow system. Physiol. Behav. 36, 83 –89. (doi:10.1016/
Pratt, B. L. & Goldman, B. D. 1986b Environmental
influences upon circadian periodicity of Syrian hamsters.
Physiol. Behav. 36, 91–95. (doi:10.1016/0031-9384
Sharma, V. K. 2003 Adaptive significance of circadian
clocks. Chronobiol. Int. 20, 901–919. (doi:10.1081/CBI-
Shibuya, C. A., Melnyk, R. B. & Mrosovsky, N. 1980
Simultaneous splitting of drinking and locomotor activity
rhythms in a golden hamster. Naturwissenschaften 67,
4546. (doi:10.1007/BF00424511)
Smale, L., Lee, T. & Nunez, A. A. 2003 Mammalian
diurnality: some facts and gaps. J. Biol. Rhythms 18,
356366. (doi:10.1177/0748730403256651)
Weinert, D., Fritzsche, P. & Gattermann, R. 2001 Activity
rhythms of wild and laboratory golden hamsters
(Mesocricetus auratus) under entrained and free-running
conditions. Chronobiol. Int. 18, 921–932. (doi:10.1081/
Field versus laboratory activity R. Gattermann et al. 255
Biol. Lett. (2008)
... Muchos factores influyen (y enmascaran) los niveles y ritmos de actividad y, en consecuencia, los patrones registrados en el laboratorio a menudo difieren de los observados en escenarios naturales (e.g. Gattermann et al., 2008;Calisi & Bentley, 2009). Así, en el capítulo 3, se exploraron el patrón de actividad, área de ocupación y uso de microhábitats en poblaciones de A. andina y P. vaccarum distribuidas en sitios a distinta altitud en la región central de la Cordillera de los Andes. ...
... ). En consecuencia, distintos estudios suelen arribar a resultados contrastantes (e.g.Gattermann et al., 2008;Kronfeld-schor & Dayan, 2008;Calisi & Bentley, 2009;Hut et al., 2012). El conjunto de reportes en A. andina demuestra que su patrón de actividad es un rasgo altamente plástico. ...
... Sin embargo, en poblaciones de A. andina de mayor altitud, se observó que la diurnalidad incrementó en contextos de Ta relativamente cálida. Muchos factores influyen (y enmascaran) los ritmos de actividad y, en consecuencia, los patrones registrados en el laboratorio a menudo difieren de los encontrados en condiciones naturales (e.g.Gattermann et al., 2008;Calisi & Bentley, 2009). Sin embargo, si los animales replicaran en el campo la respuesta conductual aquí registrada experimentalmente, su potencial capacidad para hacer frente a las proyecciones de aumento de temperatura podría verse comprometida(IPCC, 2021). ...
Full-text available
En sus hábitats, los animales deben hacer frente a condiciones ambientales más o menos variables. En particular, los ambientes de montaña son sitios altamente cambiantes, por lo que imponen un fuerte desafío al balance energético de las especies y constituyen entornos favorables para la evolución de fenotipos plásticos. La plasticidad conductual es un caso particular de plasticidad fenotípica que implica una respuesta inmediata a los cambios ambientales y constituye la primera línea de defensa de los animales ante la variación del entorno. En este sentido, emerge como un mecanismo crucial para la adecuación de las especies en el actual contexto de cambio climático. Bajo la premisa de que la conducta es un componente importante de la respuesta fenotípica para afrontar los desafíos termoenergéticos, el objetivo en esta tesis consistió en evaluar el repertorio de respuestas conductuales que los roedores andinos despliegan ante la variabilidad ambiental, a fin de comprender su capacidad de adecuación en vista de los escenarios ambientales que se avecinan. El área de estudio comprendió un gradiente altitudinal (1700 m a 3100 m s.n.m.) situado en los Andes Centrales de Argentina, en la provincia de Mendoza. Las especies estudiadas fueron: Phyllotis vaccarum, Abrothrix andina, Akodon oenos y Euneomys sp. En concreto, se observaron: la actividad locomotora y el patrón de actividad de A. andina y A. oenos ante variaciones experimentales de temperatura y disponibilidad de alimento (capítulo 2); el patrón de actividad, área de ocupación y uso de microhábitats de P. vaccarum y A. andina en entornos naturales a distinta altitud (capítulo 3); y los hábitos alimenticios a distinta altitud y momento del año de P. vaccarum, A. andina, A. oenos y Euneomys sp. (capítulo 4). El conjunto de rasgos evaluados evidencia patrones de respuesta complejos y grados de plasticidad variables, sugiriendo que la contribución potencial del comportamiento al equilibrio térmico y energético varía intra e interespecíficamente. Asimismo, las observaciones recabadas indican que, en función de sus niveles de plasticidad conductual, A. andina y P. vaccarum podrían ser capaces de morigerar los efectos del cambio climático, mientras que A. oenos y Euneomys sp. podrían verse seriamente comprometidos (capítulo 5).
... When daily activity patterns of several species have been measured in the field, these patterns appear to be decidedly different from the nocturnal activity patterns of these same animals in the laboratory (Calisi and Bentley, 2009). A landmark study that exposed switches in the temporal niche of overt behaviour in the golden hamster (Mesocricetus auratus), reported that in their native habitat in Turkey these animals exhibited crepuscular activity patterns, which contrasts the laboratory-conditions in which they are almost completely nocturnal (Gattermann et al., 2008). Similarly, when laboratory mice were housed in large outdoor enclosures exposing them to natural weather conditions they reverted their nocturnal behavioural activity rhythms, and showed multiple temporal niche switches between nocturnality and diurnality over the two-year study period . ...
... First, we would like to stress that, in their natural habitat, many small rodent species typically considered as nocturnal can indeed show extensive periods in which a substantial or even the dominant fraction of their daily activity occurs during the light phase. This includes rats, mice, hamsters and even several subterranean species Gattermann et al., 2008;Harper and Bunbury, 2015;Levy et al., 2007;Tomotani et al., 2012;Urrejola et al., 2005;reviewed in Hut et al. 2012). We propose that the danger of predation might be an important factor in favouring nocturnality in rodents and other herbivorous prey species whenever they can afford it. ...
... The opposite response, temporal niche switching of diurnal species towards nocturnality, is also not uncommon. Some rodent species that are diurnal in the field become nocturnal under certain laboratory conditions, including degus (Ebensperger et al., 2004;Kas and Edgar, 1999b), hamsters (Gattermann et al., 2008), tuco-tucos (Tomotani et al., 2012), cururos (Urrejola et al., 2005), nile grass rats (Blanchong et al., 1999) and golden spiny mice (Cohen et al., 2010a). These laboratory-to-field circadian discrepancies raise the question of whether a 'default' circadian phenotype actually exists. ...
Full-text available
Adaptive flexibility of mammalian circadian organisation Sjaak J Riede
... This can result in remarkable differences with laboratory findings. As an example, the very precise nocturnal actograms of Syrian hamsters in the laboratory contrast sharply with field recordings that show dawn and dusk activity [154]. Moreover, while it is clear from laboratory studies that food and light availability affect the phase of different clocks [26,95,96,27] and can drive timing of rest and activity cycles [111,110], the relevance of the relationship between SCN and peripheral timekeeping in driving an adaptive phenotype is far from being understood [3]. ...
... Given the similarity of the ipRGC projection to the PON and SCN, the study of light-evoked pupillary responses that reflect the activity of the PON-projecting ipRGCs can provide substantial insights into the ipRGC signals that impinge on the SCN. 154 Paul D. Gamlin ...
Moonlight is the strongest naturally and predictably occurring nocturnal light source. Thus, many species have adapted to use moonlight as a reliable timing cue, either by directly reacting to moonlight or by entraining inner oscillators, like the monthly circalunar clock.Natural moonlight is characterized by intensity, spectrum, and complex timing, which regularly changes every night and across additional timescales. In order to understand the molecular and cellular machineries underlying moon-controlled physiology and behavior, lab experiments with organisms exhibiting well-documented lunar cycles are important. Tools such as TALEN- or Cas9/Crispr-engineered mutants or transgenesis are crucial to move from correlative studies to causal relationships. However, lab experiments face the problem that commonly used artificial light sources differ greatly from sun- and moonlight.To start to overcome this limitation, we have developed naturalistic sun- and moonlight sources, which closely mimic the natural light environment.We highlight the use of these naturalistic sun- and moonlight sources using the marine bristle worm Platynereis dumerilii, which controls its timing of reproduction with a circalunar clock. Importantly, while designed for Platynereis research, these methods can also be relatively easily adapted and used to study the effects of moonlight and/or monthly oscillator systems of other species. Finally, we provide an overview on statistical analyses of circalunar data sets.Key wordsMoonSunLightSpectraMarineUnderwaterCircalunarLunarCircalunidianMonthly clocksInner calendarLight engineeringTimingReproductionCircular statistics Platynereis dumerilii
... In the laboratory, most small mammals such as mice and rats are predominantly nocturnal when food is available ad libitum. In natural habitats, however, diurnal activity patterns have been observed in many mammalian species that are typically nocturnal in captivity [15][16][17][18][19][20][21][22]. In seminatural outside enclosures, diurnal activity patterns in house mice can be induced by high levels of competition for food and can persist for several consecutive months in winter [19,23]. ...
... Similar bimodal crepuscular patterns of activity with two separate components have been observed in nocturnal and diurnal Arvicanthis under continuous conditions (i.e., DD or LL) [132,133]. Golden hamsters (Mesocricetus auratus) are nocturnal in the laboratory; however, they are mainly crepuscular in the field [17]. Moreover, house mice under seminatural conditions display more crepuscular activity than in captivity [23]. ...
Plasticity in daily timing of activity has been observed in many species, even within an individual. The temporal phase of activity under a light–dark cycle can shift by changes in light, temperature, (perceived) predation risk, food timing, and abundance. A major determinant of the phase of locomotor activity relative to the (entrained) SCN is energy balance. In the majority of restricted feeding experiments, access to a limited amount of food is restricted to a specific time of day, thereby changing both timing of food intake and energy balance. To induce food scarcity in an ecologically appropriate way, we developed the “work-for-food” paradigm for small rodents. In this paradigm, food access is determined by wheel-running activity, and the levels of (simulated) food scarcity can therefore be titrated without imposing an externally imposed timing component. This “work-for-food” paradigm enables assessment of the effect of energy balance on the daily activity rhythms of an animal, including its decision to switch temporal niche. Adaptive behavioral strategies to cope with energetic challenges may vary depending on species, sex, age, and reproductive status. This chapter provides detailed guidelines on how to carry out the “work-for-food” paradigm as a laboratory tool to investigate (molecular) mechanisms and consequences underlying flexibility of circadian and ultradian activity patterns in small rodents. Defining the mechanisms through which metabolic feedback acts on the circadian system to shift the timing of activity relative to the light–dark cycle and entrained phase of the SCN can yield important implications for human sleep, shift-work, chronotherapy, metabolic health, and (athletic) performance.Key wordsCircadianCircadian rhythm flexibilityNocturnalDiurnalUltradianWheel-running activityEnergy balance“Work-for-food”, Food restrictionAdaptive behavioral plasticity
... However, tempting as it may be, we should not assume that changes in locomotor behaviour that would appear to be adaptive, reflect a measure of fitness. This is particularly so given that rhythmic behaviour measured in the wild in rodents and insects can be very different from that observed in the laboratory (Gattermann et al., 2008;Daan et al., 2011;Vanin et al., 2012). Moving away from Drosophila, in a sophisticated study of temporal synchronisation in honeybees, Siehler et al. observe that substrate borne vibrational plus volatile cues are important for social synchrony between individuals and reveals how evolution has finetuned these highly sensitive modality to impart time information to the hive (Siehler et al.). ...
... Such observations contrast with previous reports of nocturnality in both natural (Contreras & Rosi, 1981) and experimental conditions . Different factors can condition and/or mask the activity rhythms of animals (Refinetti, 2008) and, consequently, different studies often arrive at contrasting results (e.g., Calisi & Bentley, 2009;Gattermann et al., 2008;Hut et al., 2012;Kronfeld-Schor & Dayan, 2008). The set of reports in A. andina demonstrates that its activity pattern is a highly plastic trait. ...
In mountain environments, both temperature and food availability vary strongly with altitude, leading to a major challenge to the thermo‐energetic balance of organisms. In this sense, the behavioral repertoire is crucial for animals' adequacy because it implies a short‐term response in the face of environmental changes. In this paper, we explored the behavioral versatility of Phyllotis vaccarum and Abrothrix andina (Rodentia: Cricetidae), two of the mammal species with the highest altitudinal distribution worldwide. By radiotelemetry, we analyzed the activity pattern, home range, and microhabitat selection in populations of both species inhabiting at 2300 and 3100 m altitude in the Central Andes of Argentina. We found that A. andina was diurnal at 3100 m and cathemeral at 2300 m a.s.l., while P. vaccarum was nocturnal at both elevations. Moreover, home range size was larger in A. andina males at 3100 m in contrast to females at identical altitude and males at 2300 m; while, in P. vaccarum, there were no differences according to altitude or sex. Furthermore, we recorded a complex and species‐specific microhabitat selection pattern at different altitudes. Finally, the magnitude of behavioral variability was higher in A. andina than in P. vaccarum for all the traits analyzed. These results are discussed with emphasis on the impact of behavioral traits and their plasticity for species adequacy in high‐altitude environments.
... Differences in the behavioural budget of species housed under human care when compared to wild data, specifically pertaining to nocturnal and diurnal activity are apparent. For example, captive golden hamsters (Mesocricetus auratus) are more likely to be nocturnal in their activity patterns whereas wild animals are generally active during the morning and later afternoon [48]. This evident temporal behavioural difference in a species that we are very familiar with should galvanise further research into the influence of time of day on the myriad of species that we house with which we are less familiar. ...
Full-text available
The study of animal behaviour is important for the development of husbandry and management practices for zoo-housed species. Yet, data are typically only collected during daylight hours, aligning with human work schedules rather than animal activity patterns. To remedy this, 24 h data collection is needed. This study investigated the behaviour of a captive flock of lesser flamingos to understand temporal changes in their time-activity patterns. Two remote camera traps were placed around the birds' outdoor enclosure and one within the indoor house. Counts of birds visible within specific enclosure zones were recorded from photographic data. Behaviour was defined as active or inactive, and modified Spread of Participation Index (SPI) was used to calculate enclosure zone occupancy. Results indicated that lesser flamingos are active overnight, and to a similar amount as in the daytime. Proportions of birds observed as active were significantly higher at later times of the day (i.e., dusk) when compared to the number of active birds in the morning. Enclosure usage was diverse and indoor and outdoor zones could be used by different numbers of birds at different times of the day. Variation in enclosure usage may indicate the changing needs of the flamingos when housed indoors overnight and when they have night-time access to an outdoor enclosure. This research has identified the need for further research into the nocturnal behaviour and space use of lesser flamingos and suggests the need for 24 h research in captive birds, and other zoo-held species, especially when species are locked indoors or face behavioural restriction overnight due to biosecurity measures surrounding zoonoses outbreaks, e.g., Avian Influenza.
... This can result in remarkable differences with laboratory findings. As an example, the very precise nocturnal actograms of Syrian hamsters in the laboratory contrast sharply with field recordings that show dawn and dusk activity [154]. Moreover, while it is clear from laboratory studies that food and light availability affect the phase of different clocks [26,95,96,27] and can drive timing of rest and activity cycles [111,110], the relevance of the relationship between SCN and peripheral timekeeping in driving an adaptive phenotype is far from being understood [3]. ...
Rodent studies have been critical to exposing and defining fundamental properties of biological rhythms and underlying timing systems. Studying biological timekeeping in animals is a valid curiosity in itself, and studies in rodents are also often used to model the human condition where human studies cannot be undertaken due to practical or ethical concerns. Translation of rodent models has added substantially to our understanding of human chronobiology and has exposed properties and mechanisms of mammalian biological timekeeping that are more obvious in rodents than humans, driving the chronobiological research frontier forward. In this chapter, we describe how properties of biological rhythms can be accurately described and interrogated in rodent models and how new methods and insights can continue to drive chronobiological discovery science.Key words Animal model Mouse Rat Vole Circadian Ultradian Behavior Methods Chronobiology
... Conversely, here we observed that in A. andinus from higher altitude diurnality increased in contexts of relatively warm Ta. Many factors influence (and mask) activity rhythms and, in consequence, patterns recorded in the laboratory often differ from those found under natural conditions (e.g., Gattermann et al. 2008;Calisi and Bentley 2009). However, if animals replicated in the field the behavioral response we experimentally recorded (i.e., invariant activity pattern or increased diurnality as temperature rises), their potential ability to deal with projected temperature increases could be compromised (Mccain and King 2014). ...
Environmental changes involve trade-offs to the thermal and energetic balances that animals face through a diversity of physiological and behavioral strategies. In Abrothrix andinus and Akodon spegazzinii, two small rodents inhabiting the Andes Mountains, some physiological traits relevant to their thermal and energetic balance (e.g., conductance, basal metabolic rate) show relatively low plasticity. Therefore, behavioral plasticity could be a crucial mechanism for their adaptation to the environmental variability of their habitats. Following the circadian thermo-energetic hypothesis, we explored the frequency and pattern of locomotor activity in response to different energetic demands caused by experimental variations in ambient temperature (5, 16, and 31 °C) and food availability (ad libitum and deprivation) in these species. Our data revealed that the behavioral strategy for coping with such challenges differs among species and populations, and suggest that, depending on the particular ecological context, it may facilitate or hinder thermal and energetic balance. Furthermore, we found that, consistently with a more limited altitudinal distribution, A. spegazzinii exhibits lower behavioral plasticity than A. andinus. In the context of global climate change, phenotypic plasticity is key to species resilience, and the assessment of behavioral traits provides fundamental inputs for modeling the potential impact of future scenarios on the persistence of small highland mammals.
Syrian hamsters show complex social play behavior and provide a valuable animal model for delineating the neurobiological mechanisms and functions of social play. In this review, we compare social play behavior of hamsters and rats and underlying neurobiological mechanisms. Juvenile rats play by competing for opportunities to pin one another and attack their partner's neck. A broad set of cortical, limbic, and striatal regions regulate the display of social play in rats. In hamsters, social play is characterized by attacks to the head in early puberty, which gradually transitions to the flanks in late puberty. The transition from juvenile social play to adult hamster aggression corresponds with engagement of neural ensembles controlling aggression. Play deprivation in rats and hamsters alters dendritic morphology in mPFC neurons and impairs flexible, context-dependent behavior in adulthood, which suggests these animals may have converged on a similar function for social play. Overall, dissecting the neurobiology of social play in hamsters and rats can provide a valuable comparative approach for evaluating the function of social play.
Full-text available
Activity patterns in animals are influenced by a number of factors, including the animal's physiological adaptations, prey availability and distribution, and disturbances caused by predators and humans. We compared coyote (Canis latrans) activity patterns estimated using radio-tracking locations between 1983 and 1988 with those documented between 1996 and 1997 on the Pinon Canyon Maneuver Site, in southeastern Colorado. We tested the hypothesis that changes in the type of disturbance experienced by coyotes would result in changes in their activity patterns. Disturbance experienced by the coyote population studied during 1983-1988, included > 50 years of intense exploitation (shooting and trapping by ranchers) and intensive removal efforts using aerial gunning. In contrast, coyotes tracked during 1996-1997 experienced some periodic disturbance from army maneuvers occurring in the area, but were not exposed to any direct form of persecution (e.g., shooting). From August 1983 to July 1988, 49 coyotes (26 males and 23 females) were tracked for > 2400 h using radiotelemetry. From April 1996 to August 1997, 22 coyotes (12 males and 10 females) were tracked for > 950 h. The average rate of diurnal movement of the coyotes in the 1996-1997 field study ((x) over bar = 0.97 km/h) was significantly higher than that of the coyotes in the 1983-1988 field study ((x) over bar = 0.68 km/h). This occurred despite no significant increase in the overall (24 h) rate of movement between the two field studies. Estimates of prey use by the coyotes in both field studies were obtained, to test an alternate hypothesis that prey switching might explain the changes in coyote movement patterns. However, there was no significant difference between the frequency of occurrence of diurnally versus nocturnally active mammalian prey species in the diets of coyotes in any season or overall between the 1983-1988 and 1996-1997 field studies. This study demonstrated that coyote activity patterns can be influenced by the type of disturbance experienced by the animal. A coyote population that had historically been exposed to human persecution shifted to higher levels of diurnal activity when exploitation ceased.
Full-text available
Two expeditions were carried out during September 1997 and March 1999 to confirm the current existence of Mesocricetus auratus in northern Syria. Six females and seven males were caught at different sites near Aleppo. One female was pregnant and gave birth to six pups. Altogether, 30 burrows were mapped and the structures of 23 golden hamster burrows investigated. None of the inhabited burrows contained more than one adult. Burrow depths ranged from 36 to 106 cm (mean 65 cm). Their structure was simple, consisting of a single vertical entrance (gravity pipe) that proceeded to a nesting chamber and at least one additional food chamber. The mean length of the entire gallery system measured 200 cm and could extend up to 900 cm. Most burrows were found on agricultural fields preferentially on leguminous cultures. The distribution of golden hamsters is discussed in association with historical data, soil types, geography, climate and human activities. All 19 golden hamsters were transferred to Germany and, together with three wild individuals supplied by the University of Aleppo, form a new breeding stock.
Although Norway rats (Rattus norvegicus) generally are nocturnal, we have found a wild population showing diurnal activity. Three hypotheses could account for this aberrant behavior: subordinate rats forage diurnally to avoid dominant individuals; minimal disturbance facilitates diurnal activity; rats avoid predation by nocturnal red foxes (Vulpes vulpes). To test predictions generated by these hypotheses, we studied activity and movement patterns of rats and foxes and found that only the predictions of the predator-avoidance hypothesis were fulfilled. We then tested this hypothesis experimentally by keeping rats captured from the diurnal population in a fox-proof enclosure. Rats in the enclosure reverted to normal nocturnal behavior. We believe, therefore, that rats timed their activity to avoid predation from foxes. Our results provide the first example of a mammalian prey species altering the timing of its foraging to avoid a predator.
Bunning's general proposition, that circadian rhythmicity underlies the photoperiodic time-measurement, is, in our view, correct. In the first place the proposition seems highly plausible, a priori, in view of the diversity of other chronometric functions such rhythms subserve. In the second place there is a large body of experimental fact that cannot reasonably be interpreted in any other way. A "Coincidence Model" for photoperiodic induction is outlined; it is essentially Bunning's original scheme given in somewhat more explicit terms. It may yet prove true that the "coincidence-device" type of model will prove inadequate; but that would not necessarily render Bunning's more general proposition invalid-that the circadian system somehow executes the time-measurement. In any event we note that any general theory of circadian oscillations as photoperiodic clocks must go well beyond the terms in which the proposition was first stated; and specifically it must incorporate a general theory of the entrainment ...
Provides a comprehensive textbook for use in biological rhythms courses at both the advanced undergraduate and graduate levels and provides a nontechnical source book for scientists in other fields. As a result of the broad scope of this book, it may be used in diverse programs including neuroscience, biology, plant physiology, psychology, ecology, or medical physiology. Each chapter begins with an opening spread that guides the reader by bridging consecutive chapters and providing an overviews of the chapter at hand. Many of the chapters start with a brief historical overview to help acquaint readers with the field. At the end of Chapters 1-10 are sections entitled Study Questions and Exercises, which have been designed to give insights, provide practical experience, and suggest ideas for additional library- or laboratory-based research into chronobiology. The overarching themes of this book are summarized in 4 Plates that contain collages of full-color photographs. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The environment of any animal species is a complex set of both abiotic and biotic qualities. Dominant abiotic parameters are light conditions, ambient temperature, relative humidity, precipitation, and wind speed. Biotic components may be classified by the trophic levels at which they occur. On the same trophic level we find conspecifics as mates, as members of a social group, and as competitors. On the same trophic level there are also competitors from other species. Biotic components from different trophic levels are represented by prey, predators, and parasites. The combination of all these factors determines how the world looks for an individual at a specific moment in time.
Inaug.-Diss.--Berlin. "Abdruck aus der Zeitschrift für Säugetierkunde [Bd.] 7." Lebenslauf. "Literaturverzeichnis": p. 237-240.