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Notes on the current distribution and the ecology of wild golden hamsters (Mesocricetus auratus)


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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.
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Notes on the current distribution and the ecology of wild
golden hamsters (Mesocricetus auratus)
R. Gattermann
*, P. Fritzsche
, K. Neumann
, I. Al-Hussein
, A. Kayser
, M. Abiad
and R. Yakti
Institute of Zoology, University of Halle, 06108 Halle (Saale), Domplatz 4, Germany
University of Aleppo, Aleppo, Syria
(Accepted 16 August 2000)
Two expeditions were carried out during September 1997 and March 1999 to con®rm 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 ®elds 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.
Key words: golden hamsters, behaviour, ecology, reproduction, Syria
The Syrian or golden hamster Mesocricetus auratus
(Waterhouse, 1839) is one of the best-established experi-
mental animals and probably among the most popular
pets in the western world. A wealth of data on the
behaviour, chronobiology, immunology and physiology
of the species have been obtained from laboratory-bred
individuals. The entire laboratory population of golden
hamsters originated from a single brother±sister pairing
in 1930 (Aharoni, 1932) with the exception of 12 wild
animals brought to the U.S.A. in 1971 (Murphy, 1985).
Since then only a few golden hamsters have been caught
in Syria and Turkey (Table 1). In contrast to the
popularity of the hamster, virtually no data exist con-
cerning its ecology, population genetics or even its
recent occurrence in the wild. This is partially because
of its narrowly restricted distribution area. Two expedi-
tions were organized to furnish proof of the existence of
golden hamsters in northern Syria and if possible to
acquire wild animals for behavioural and genetic
Joint expeditions by the universities of Halle (Germany)
and Aleppo (Syria) were led to northern Syria in late
summer 1997 and spring 1999. The aim of the ®rst
expedition (30 August±13 September 1997) was to
explore the presumed distribution area around Aleppo
and to identify suitable hamster habitats. The hamster
search included the location of used burrows and an
attempt to catch animals with live-traps baited with
apple and melon pieces. Interviews with village elders
and economists were carried out. A photograph of the
golden hamster was shown to the interviewees who then
had to describe the typical features of a golden hamster
burrow as well as morphological characteristics of the
animal itself, including differences from other related
species, e.g. the grey hamster Cricetulus migratorius.
The second expedition from 4 to 27 March 1999 was
led to the most promising hamster sites. Twenty-three
burrows were excavated, measured and where possible
the animals caught. Means and standard deviations of
all measurements are presented. Additionally, a typical
soil pro®le was drawn up in the region near Azaz. The
characterization of the soil horizons followed Scheffer &
Schachtschabel (1998) and Spaagaren (1994). Two data
loggers (OTLM Gemini Data Loggers (U.K.) Ltd) were
used to monitor the air temperature 70 cm above
J. Zool., Lond. (2001) 254, 359±365 #2001 The Zoological Society of London Printed in the United Kingdom
*All correspondence to: R. Gatterman
ground and the soil temperature at a depth of 70 cm.
Registration was carried out every 12 min. The locations
of all hamster burrows were assessed using a GPS-
location system (GPSMS1 from m-blox, Switzerland).
Altogether 13 hamsters, seven males and six females,
were caught at two locations near Albel/Shaykh-Rieh
and Arnaz about 50 km north-east and 20 km south-
west of the city Aleppo, respectively (Table 2). Average
adult body weight was 99.5  5.9 g ( sd) for males
(n= 6) and 76.0  13.7 g for females (n= 3). One female
was pregnant (excluded from body measurements) and
gave birth to six offspring. Three 2- to 3-week-old
juveniles (one male and two females) were found inside
burrow 30, which had been used for several years. There
were no obvious morphological differences in compar-
ison to laboratory animals except that the coloration of
wild hamsters seems slightly more intense.
Eleven animals were excavated from their burrows.
Local farmers trapped two other individuals by ¯ooding
the burrows. Only one female showed several scabbed
bite marks on her back. All other hamsters were in good
physical condition without injuries or obvious bite
marks and were free of ectoparasites.
Burrow structures
Thirty hamster burrows were found and mapped.
Twenty-three were excavated and measured. Complete
data are only available for 18 burrows, since not all the
tunnels in the remaining burrows were detected. Fully
excavated burrows without hamsters were categorized
as hamster `absent' if clear signs of activity (e.g. fresh
green plant material) were detected or as `deserted'
when lacking such signs (Table 2).
Burrow depths varied between 36 and 106 cm and
averaged 64.8  17.6 cm. The mean total tunnel length
was 199.5  92.6 cm and could range for > 9 m (burrow
30). The burrow entrances measured 4±5 cm in diameter
and led into a vertical tunnel 18±45 cm long ± the
R. Gattermann ET AL.360
Table 1. List of historic and recent distribution records of golden hamster Mesocricetus auratus
Location Date Reference Remarks
1 Aleppo (?)
1797 Russel & Russel, 1797 Earliest description of the golden hamster
Aleppo (?) 1839 Waterhouse, 1839 Type specimen, probably caught by the Russel brothers
Aleppo (?) 1880 Reynolds, 1954 J. H. Skene, Consul General at Aleppo brought living
hamsters to Britain
Aleppo June 1902 Nehring, 1902 1 preserved ,was sent to Berlin by Zumoffen (Beirut)
Aleppo 12 April 1930 Aharoni, 1932 1 ,and 11 juveniles were excavated by I. Aharoni, 3 << and
1,are the ancestors of all captive golden hamsters
Aleppo (?) 1962/1972 Kumerloeve, 1975 3 hamsters were caught and sent to Turkey (1) and to the
U.S.A. (2)
Aleppo Autumn 1982 Ch. Henwood, 1 <and 1 ,were caught, ,was brought alive to London,
pers. comm. cross-pairing with laboratory hamsters failed
Aleppo May±June 1971 Murphy, 1971 13 hamsters were trapped, 4 << and 8 ,, were transferred
to the U.S.A. and separate breeding stock established
(Coe & Ross, 1997)
Aleppo 1978 Murphy, 1985 2 ,, were brought to the U.S.A. by B. Duncan
2 Biliramun April 1930 Aharoni, 1932 Further 3 ,, were collected by I. Aharoni, the skulls are in
3 Azaz April 1930 Berlin
4 Antakya (?) Spring 1949 Eisentraut, 1952 According to Eisentraut a gravid ,was caught 20 km east
of Antakya and 2 << offspring were taken to Germany.
This ®nding was not con®rmed by others and has to be
5 Jarablus 1986 H. Tichy, pers. comm. 3 << were brought to Tu
Èbingen (Germany), cross-pairing
with laboratory hamsters failed
6 Kesiktas July 1991, 1996, Dogramaci et al., 1994; 4 hamsters were collected for taxonomic studies
1997 H. Kefelioglu, pers.
7 Kilis Spring 1999 N. Yigit , pers. comm. 1 <and 1 ,were sampled for taxonomic studies, further
records in Yigit et al., 2000
8 Albel March 1999 This paper 7 << and 6 ,, caught at Albel (3,2), Shaykh-Riek (1,1) and
9 Shaykh-Riek Arnaz (3,3); 30 burrows were mapped and 18 measured
10 Arnaz The hamsters were transported to Halle (Germany) and
form the source of a new breeding stock
See Fig. 1.
(?) Uncon®rmed reference.
`gravity pipe'. Occupied burrows were always plugged
with a lump of earth, which was missing in unused
burrows. On average the sealing was placed about
22 cm below the surface. The smallest plug extended
only 5 cm into the burrow but some extended up to
10 cm. After the gravity pipe, the tunnel levelled out
and continued at a slight angle further downward to the
nest chamber. The 10- to 20-cm-wide nest chamber was
located 58.3  12.7 cm below the surface. Its interior
consisted of a spherical nest made of dry plant material.
Two nests included textile remnants, bird feathers and
shredded plastic sack pieces in the nesting material. At
least two tunnels divided from the chamber. A 10±15 cm
blind-ending tunnel was apparently used for urination.
Faeces were found throughout the entire burrow. The
remaining tunnels measured about 100±150 cm and ran
deeper at varying angles and were partially used for
food storage. Ten burrows contained a varying amount
of green plant material such as chickpea and were there-
fore considered as inhabited. In three deserted burrows,
only old or rotten grain (barley, weed) was found. The
remaining burrows were empty. Three deserted burrows
were being used by green toads Bufo viridis. No differ-
ences between female and male burrows were detected.
However, the largest and most complex burrow
excavated contained three juveniles and apparently
belonged to a female with her litter.
The burrow density for the agricultural ®elds around
Azaz could only be estimated. Fifteen burrows (six
occupied, nine `empty') were located in an area of 30 ha.
The shortest distance between burrows measured 38 m.
However, the closest distance between occupied hamster
burrows was 118 m. Grassy embankments exhibited
higher burrow densities but the degree of occupation
could not be assessed.
Habitat and geographical distribution
Burrows were found mainly in ®elds with annual crops
comparable with the preferences of common hamsters
Cricetus cricetus in Europe. Most frequently these were
weed, barley, chickpea, lentil and fruits and vegetables
such as melon, tomato, cucumber and hibiscus. Fields
had to be irrigated depending on the type of culture.
Normally, 2 years of cereal crop are followed by a single
year of leguminous cultures. Refuge areas like barren
bushes or hedges were often missing as a result of the
increasing urban spread and extensive farming. Even
ridges to mark the ®eld boundaries of neighbouring
361Distribution and ecology of wild golden hamsters
Table 2. Measurements of golden hamster burrows and trapped inhabitants
Total tunnel Max depth Depth of nesting Entrance Gravity pipe Depth of the Inhabitant, body weight,
Burrow length (cm) (cm) chamber (cm) diameter (cm) length (cm) clot (cm) location and remarks
1 90 62 60 4,5 34 20 Adult ,, 103 g, Albel
3 270 57 50 Deserted, Albel
4 220 55 54 4 19 19 Adult <, 88 g, Albel
5 270 48 48 4,5 18 Deserted, Albel
6 170 75 65 None Absent, Albel
7 Adult <, 93 g, Albel;
¯oated to the surface
8 Adult ,, 67 g, Albel;
¯oated to the surface
in bad condition
10 100 36 36 4 Deserted, Albel
12 215 106 55 4,5 25 15 Adult <, 97 g, Albel
> 90 4 35 17 Not found, Albel
14 126 65 65 36 36 Adult <, 99 g, Arnaz
15 235 53 45 4 Deserted, Arnaz
17 150 70 None 5 38 Deserted, Arnaz
18 177 70 70 4 45 Deserted, Arnaz
> 150 70 50 5 30 Adult ,, 114 g, Arnaz;
20 363 69 60 4,5 26 Deserted, Arnaz
> 180 80 5 25 Not found, Arnaz
> 285 93 93 4,5 24 24 Not found, Arnaz
23 130 58 53 4 25 Deserted, Arnaz
25 105 60 None 4 15 15 Adult ,, 58 g, Shaykh-Rieh
26 130 100 None 4 20 Adult <, 92 g, Shaykh-Rieh
63 63 4,5 33 14 Not found, Shaykh-Rieh
28 220 47 47 4,5 23 Adult <, 128 g, Arnaz
29 420 70 70 5 25 Deserted, Arnaz
> 900 85 65 5 25 17 Juveniles: <,30g,
,,23g,,, 29 g, Arnaz
Mean 199.5 64.8 58.3 4.4 28.2 21.2
SD 92.6 17.6 12.7 0.4 8.3 6.4
Burrows with incomplete data that were not included in all calculations.
villages were restricted. Only roadsides and narrow
barren stripes around irrigation wells remained as alter-
native hamster sites.
The main distribution area (Fig. 1) of the golden
hamster lies in the fertile, agricultural and densely
populated Aleppinian plateau in Syria, 280±380 m
above sea level. The area covers only 10 000±15 000 km
and ranges north and south-west of the city of Aleppo.
The North-Syrian limestone massif and the Turkish
Taurus mountains form the natural western and
northern barriers. The River Euphrates limits the range
to the east and the stony steppe can be considered as an
invincible barrier in the south-east. The south limit has
not yet been de®ned but may reach as far as the
beginning of the Syrian desert.
In addition to our observations, sightings of the
golden hamster have been reported from Jarablus in
Syria, and Kilis and Kesiktas (near Gaziantep) in
Turkey (Dogramaci, Kefelioglu & Gunduz, 1994;
H. Kefelioglu, pers. comm.; N. Yigit, pers. comm.;
Table 1, Fig. 1).
Climate and soil conditions
The climate of the studied area was continental with
large seasonal and diurnal ¯uctuations (Fig. 2) and low
rainfall of 336 78 mm/year. The winter season was wet
and cold with temperatures of c.108C. There were
occasional spells of frost or snow. The annual number of
frosty days averaged 35.2, with absolute minimum tem-
peratures of 74to798C (Anonymous, 1991±92). Based
on our data, temperatures in August and September
reached 35±38 8C at midday and 30±32 8C close to
sunset. Along with shading light and the beginning of the
hamsters' surface activities (according to laboratory
observations), temperatures fall rapidly to 15 8C at mid-
night and c.68C immediately before sunrise. March
temperatures varied between 4.6 and 18.4 8C, 70 cm
above ground. In contrast, below-surface measurements
revealed an almost constant temperature of 12 8C. Only
low ¯uctuations from 11.9 to 12.2 8C were detectable at a
depth of 70 cm, where the nesting chamber usually lies.
Soils based on sandy clay materials overlaying lime-
stone are the dominant soil types found in hamster areas.
All excavated burrows were on light-brownish chromic
cambisols (terra fusca) or red rhodochromic cambisols
(terra rossa). Both soil types have a high clay component
and the resulting high plasticity provides optimal con-
ditions for fossorial animals. Table 3 shows a chromic
cambisol pro®le with the typical structure found in the
regions. The potentially available water capacity is high
in comparison to most soil types found in Central
Europe. However, the actual capacity is probably much
R. Gattermann ET AL.362
10 2
50 km
750 m
750 m
Fig. 1. Distribution map of the golden hamster Mesocricetus auratus. Numbers indicate historic and recent records according to
literature and personal communication (see Table 1).
lower because of the dry climate. The clay-rich soil
exhibits low water conductivity, particularly in the less
rooted subsoil.
During the two short stays in the main distribution area
of the golden hamster, only a limited number of biolo-
gical data could be obtained. Nevertheless, our ®ndings
disprove occasional opinions that the golden hamster
has become extinct and the existence of M. auratus
populations was con®rmed.
Aharoni (1932) reported M. auratus from three dif-
ferent locations in Syria (Aleppo, Biliramun, Azaz) and
Murphy (1971) collected hamsters near Aleppo. We
found golden hamsters at two sites about 19 km south-
west of Aleppo and 13 km east of Azaz, respectively.
Another three males were recorded near Jarablus 90 km
east of Azaz (H. Tichy, pers. comm.). Two known
populations on the Turkish side exist at Kilis (15 km
north of Azaz) and near Gaziantep (54 km north of
Azaz). The Turkish and Syrian sites may form a con-
nected distribution area, but data linking the currently
known populations are missing, e.g. from the military
protected border zone between Syria and Turkey.
The natural habitat of the golden hamster is described
as rocky steppe or brushy slopes (Clark, 1987). In
contrast, almost all our golden hamsters were excavated
from burrows on agricultural land. The search for signs
of hamster activities in steppe areas around the town of
Afrin during summer 1997 ended without success. This
®nding corresponds with Aharoni (1932), who described
the species from cultivated grain ®elds. Most burrows
were found on plots with leguminous cultures. This may
be an indication of existing preferences. Others found
M. auratus on grassy embankments (Reynolds, 1954;
Harrison, 1972). In fact we obtained a single individual
from such sloping ground and identi®ed several
burrows on embankments near irrigation wells. To our
knowledge there is no evidence for current sightings of
golden hamsters in true steppe habitats in Syria. Litera-
ture reports about steppe populations probably result
from confusions with the Turkish hamster Mesocricetus
brandti, a rather similar species occurring in many other
countries of the Near East. The golden hamster, like
many steppe animals such as the common hamster
C. cricetus in middle Europe, has developed a prefer-
ence for the abundant, food rich and optimal ground
conditions provided by agricultural sites in northern
Syria. The destruction of natural steppe habitats in
Syria has certainly accelerated this process of adapta-
tion. The species distribution is presumably patchy but
the hamsters may be locally abundant according to our
own observations and those of local farmers.
Previously published burrow structures by Herter &
Lauterbach (1955), Dieterlen (1959) and Ropartz (1962)
have been obtained under laboratory conditions, e.g.
limited space, and do not entirely agree with our
measurements. The sole data of a natural hamster
burrow belong to that excavated by Aharoni in 1930,
who described the location of a nest with pups at a
depth of 2±2.5 m (Aharoni, 1932, 1942). These data are
not in concordance with our ®ndings either (Table 2)
and may represent an extreme value. The relatively
simple structure of the golden hamster burrow is rather
different from those of common hamsters C. cricetus,
which often exhibit > 10 branches (Grulich, 1981). The
lack of variation between male and female burrows may
be due to the early breeding season. For common
hamsters it has been reported that sex-speci®c differ-
ences in burrow structures are only observed in female
burrows depending on whether they contain litters
(Grulich, 1981; Weidling & Stubbe, 1998). This could
explain the exceptional structure of burrow 30 (Table 2).
Only a single adult golden hamster was found in
363Distribution and ecology of wild golden hamsters
Precipitation (mm)
Sep Nov Jan Mar May Jul 0
Temperature (°C)
Fig. 2. Maximum and minimum temperatures (lines) and total
precipitation (bars), for the natural distribution area of the
golden hamster in northern Syria. Mean values are given for
1978±92. Data by the meteorological station Tel Hadya, about
35 km south-west of Aleppo (Anonymous, 1991±92).
Table 3. Soil pro®le taken near Albel
Depth CaCO
Density Sand Silt Clay Fine roots
No Horizon
(cm) Colour pH (CaCl
) (%) (g/cm
) (%) (%) (%) Structure (per dm
1 Agric 725 5YR 3/6 7.41 2±4 1.25±1.45 0±45 0±20 40±60 Granular 6±10
2 Chromic 760 5YR 4/6 7.39 2±4 1.45±1.65 0±45 0±20 40±60 Subangular 3±5
cambic 1 blocky
3 Chromic 796 5YR 5/6 7.50 2±4 1.45±1.65 45±65 0±10 35±55 Subangular 1±2
cambic 2 blocky
4 Calcaric >796 5YR 7/4 7.32 > 10 > 1.85 65±80 0±20 20±35 ± 0
Horizon description and colour follows Scheffer & Schachtschabel (1998) and Spaagaren (1994).
every burrow, which may be evidence that they are
solitary in the wild, supporting the general characteriza-
tion of this species. Laboratory studies have shown
that arti®cial grouping leads to symptoms of stress
(Gattermann & Weinandy, 1996±97).
According to local farmers, hamsters disappear in
November and show ®rst signs of activity at the begin-
ning or middle of February. Whether these observations
can be interpreted as an indication of the existence of a
hibernation period remains unclear. In laboratory
experiments, hibernation could be induced by keeping
golden hamsters at temperatures below 8 8C (e.g. Smit-
Vis & Smit, 1963; Ueda & Ibuka, 1995). Unfortunately,
no long-term soil temperatures for the depth of the
burrows were available for northern Syria, but air
temperatures may drop well below 0 8C during the
winter. No data concerning the reproduction of golden
hamsters in the wild exist. However, the presence of 2-
to 3-week-old juveniles in one of the excavated burrows
and the capture of a gravid female which gave birth on
24 March indicate that reproductive activity may start
as early as February. This falls well within the time of the
animals' reappearance according to our questionnaire.
During these interviews the rural population repeatedly
mentioned gradations and the last appearances, which
occurred in 1995 around Azaz.
Natural predators of hamsters such as foxes, muste-
lids or owls are scarce or hunted down. The same
applies to larger reptiles or snakes. Other birds of prey
may only occasionally take a golden hamster because of
its nocturnal behaviour, but the presence of hamsters in
their diet cannot be quanti®ed since no data are avail-
able. Overall, the impact of natural predators on
hamster populations can probably be ignored. Stray
dogs are abundant but probably do not endanger
golden hamsters. In contrast, human activities are dras-
tically affecting the occurrence of golden hamsters in
several ways. Hamsters are considered to be the most
important agricultural pest besides the vole Microtus
sociales, which was often found on the same plots.
Control measures start in February as soon as the
burrow entrances become visible. Animals are trapped
or poisoned. The rural population applies large
amounts of rodenticides provided by the government.
In May±June most ®elds are harvested, burnt and
ploughed. Sheep herds feed on the remaining plants and
grain. At this time it may become increasingly dif®cult
for hamsters to ®nd cover, nutrition or suf®cient food
for winter storage.
Above all, increasing human settlement caused by an
immense population growth of 3.34% per year provides
the main threat to the golden hamster in Syria. However,
until now there are insuf®cient data to evaluate the
abundance and population dynamics of the species and
its distribution has not yet been fully clari®ed.
The captured golden hamsters were brought to the
Institute of Zoology in Halle and a breeding stock was
set up that has already produced several offspring.
Behavioural and genetic studies on potential differences
between wild and laboratory hamsters are currently
underway and scienti®c co-operation is welcome. The
breeding population of wild golden hamsters in Halle
can also be used to enhance the genetic variability of
current golden hamster strains.
The authors are indebted to the President of the
University of Aleppo, Dr M. A. Hourieh, for the great
hospitality and support for the expeditions. We thank
Dr M. Hoffmann for the technical assistance and
K. Williams for correcting the English. This study was
supported by Deutscher Akademischer Austauschdienst
and Gruner & Jahr Verlag Hamburg.
Note added in proof:
After submission of this paper Shehab, Kowalski &
Daoud (1999) reported that M. auratus remains were
found in owl (tyto alba) pellets collected in the Ebla
ruins, 70 km south of Aleppo. The co-ordinates of this
site coincide well with the southern edge of our provi-
sional distribution map (®g. 1).
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365Distribution and ecology of wild golden hamsters
... The Syrian hamster, Mesocricetus auratus (Waterhouse 1839), was originally described from Aleppo, Syria. Gattermann et al. (2001) presented a distribution map for the Syrian hamster and showed that it is confined to the west of the Euphrates, along a narrow strip in Turkey bordering Syria, reaching Arnaz to the west of Aleppo. Localities for this species from Turkey include a doubtful report for Antakya (Eisentraut 1952), Kesiktas (Dogramaci et al. 1994), Kilis and Şanliurfa (Yiğit et al. 2000(Yiğit et al. , 2003, Nizip (Kryŝtufek and Voharlík) and Elbeyli (Larimer et al. 2011), and materials recovered from owl pellets collected from Ebla ruins and Yahmool (Shehab and Al Charabi 2006;Shehab et al. 1999Shehab et al. , 2004 from Syria. ...
... Two more fresh burrows were observed within the barley field bout 50 m away from the first inhabited burrow. Gattermann et al. (2001) speculated that the southern limit for this species may reach as far as the frontiers of the Syrian Desert. The present record substantiate this presumption. ...
... Possibly, south Homs plains represent the southern boundaries at the most north-western tip of the Syrian Desert and the northern and southern Palmyra mountain range (Figure 2). Gattermann et al. (2001) gave details on the structure of M. auratus burrows, with a maximum length and depth reaching up to 2 m and 106 cm respectively. Larimer et al. (2011) studied the foraging behavior of the Syrian hamster in Turkey, and showed that hamsters spend short time (about 1 h daily) outside their burrows. ...
A new occurrence record significantly expanded known distribution limits of the Syrian hamster further south into the Syrian Desert, about 150 km to the south from the known southern range border is reported. Updated distribution map for this species is given based on previous records from Syria and Turkey.
... Light/dark phase Circadian effects Physiological effects [8-10, 13, 18, 21-23] Drugs interaction effects [13][14][15][16][17]20] Learning tasks [17,25,26] Pain perception [24] Testing behavior during dark phase [10] Keeping all types of lighting dim during testing, including red light [11,12] Transportation Stress Immune function [29] Reproduction [40,41] Development [33][34][35] Breed animals in lab or avoid shipping during puberty Consider "two-hit" model if shipping pregnant animals [45] Allow time for animals to acclimate before testing [31,32] Home Cage Environment Cold Stress [51,53] Hormone levels [52,[55][56][57], Behavior [60][61][62][63][64] If forced air caging is unavoidable, add extra bedding or enrichment for thermoregulation [66,68] Avoid behavioral testing on cage change days [60,61] Intermix experimental groups that are housed on separate levels [63] Social Environment Hormone levels [76,77] Aggressive behaviors [73][74][75]78] Evolutionary history [71,72,[91][92][93] Record social ranking within cage [64,82,87,88,90] House animals based on species specific behavior Use alternative strategies to house animals after surgery recovery H.M. Butler-Struben et al. ...
... Although domesticated mouse and rat lines are used for the majority of rodent studies, there are many other rodent species with different social systems that are well suited for behavioral pharmacology studies. The Syrian hamster is a solitary species [91] in which single housing does not appear to be a stressor [92]. In contrast, prairie voles generally live in family groups [93] and are especially sensitive to social isolation [94]. ...
The field of neuropsychopharmacology relies on behavioral assays to quantify behavioral processes related to mental illness and substance use disorders. Although these assays have been highly informative, sometimes laboratories have unpublished datasets from experiments that “didn’t work”. Often this is because expected outcomes were not observed in positive or negative control groups. While this can be due to experimenter error, an important alternative is that under-appreciated environmental factors can have a major impact on results. “Hidden variables” such as circadian cycles, husbandry, and social environments are often omitted in methods sections, even though there is a strong body of literature documenting their impact on physiological and behavioral outcomes. Applying this knowledge in a more critical manner could provide behavioral neuroscientists with tools to develop better testing methods, improve the external validity of behavioral techniques, and make better comparisons of experimental data across institutions. Here we review the potential impact of “hidden variables” that are commonly overlooked such as light-dark cycles, transport stress, cage ventilation, and social housing structure. While some of these conditions may not be under direct control of investigators, it does not diminish the potential impact of these variables on experimental results. We provide recommendations to investigators on which variables to report in publications and how to address “hidden variables” that impact their experimental results.
... Physically, they are stout-bodied with distinguishing features that comprise elongated cheek pouches extending to their shoulders, used to carry food back to their burrows, as well as a short tail and fur-covered feet (Figure 23). Depending on the species, they have silky fur long or short, colored gray, black, white, honey, brown, red, yellow or a mix [43]. ...
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Strawberries Fragaria ananassa Duch., are delicious and packed with nutrition, so not just only humans love to eat them, but are tasty and nutritious to many other creatures. Unfortunately, birds, rodents and a range of other pests may harshly injury to strawberry plants. Thus, purpose of this chapter is enhancing protections against these vertebrate culprits to mark the dissimilarity among an awkward and normal plants. Numerous species of birds consume strawberries that are among the most common pests and as well challenging to manage for the reason that they are very moveable. Frightening maneuvers, such as noisemakers and fake owls or hawks, to some degree are operative, however they might be regularly changed since birds become accustomed to them. Physical hurdles, such as netting and wire mesh are further operative and plants must be completely covered with them, though it is labor-intensive to install. Various rodents might eat strawberries including rats, mice and squirrels, however rabbits may likewise create harms. Physical obstacles will typically retain these pests outside of orchards, even though to this tactic, there are few challenges. Several rodents particularly mice are enough smaller to slipup under or through fences. Barriers used to retain smaller animals out should be prepared from good netting and the bottommost might be tight completely alongside the earth, or be submerged a few centimeters underneath, and likewise netting row shelters above plants might be effective. Deer will also feast on strawberries, but a few more control options are available for these animals than for birds. Physical barriers, like wire mesh row covers can also be effective and electric fences around an entire garden might keep deer out. A combination of methods used in this work are best to protect strawberry plants, but nothing is 100% guaranteed when a foraging pest is truly motivated.
... We did see sex differences with the body composition data, though, such that females had a higher percentage of lean mass and total water weight (Fig. 3A, 3B). Males are usually leaner than females [5,44], but the differences in body composition in hamsters might relate to ethological differences between female and male Syrian hamsters [1,13]. ...
A reduction in the rewarding properties of social interactions is frequently a key contributor to neuropsychiatric disorders. Although much remains to be learned about the neural mechanisms governing social reward, numerous studies have found that oxytocin can enhance the salience of rewarding social interactions. As a result, oxytocin has been suggested as a pharmacotherapy for disorders characterized by a dampening of social motivation. However, exogenous oxytocin does not cross the blood-brain barrier effectively, which has led to the investigation of alternative approaches to induce central oxytocin release, such as pharmaceuticals targeting melanocortins. Although oxytocin treatment is widely viewed to increase prosociality, there is also recent evidence that high concentrations of oxytocin can decrease social reward. In the present study we tested the hypothesis that alpha-melanocyte-stimulating hormone (αMSH) influences the rewarding properties of social interactions by acting on oxytocin receptors. Male and female Syrian hamsters were given intracerebroventricular infusions of saline, αMSH, or a cocktail containing αMSH and an oxytocin receptor antagonist during social conditioning with a same-sex hamster and then tested for a conditioned place preference. αMSH decreased preference for the socially-paired chamber compared to saline treatment, and administration of the oxytocin antagonist concurrent with αMSH administration returned subjects’ preference to control levels. Importantly, αMSH treatments did not affect any measures of body composition or the specific social behaviors displayed during conditioning. These data suggest that melanocortin-targeting drugs should be administered carefully to avoid the possibility of decreasing the rewarding properties of social interactions.
... This is, in part, because of challenges associated with defeating female mice and rats (Haller et al., 1999;Harris et al., 2018;Newman et al., 2019;Takahashi et al., 2017). However, both male and female Syrian hamsters readily engage in territorial aggression and experience social defeat (Albers et al., 2002;Bastida et al., 2009;Gattermann et al., 2001;Lai et al., 2005;Lai and Johnston, 2002), allowing for ethologically relevant examinations of behavioral responses to social stress in both sexes (Huhman et al., 2003). Examining the relationship between acute SSRI treatment and social stress in females is essential, given that females are more than twice as likely to be diagnosed with either MDD or PTSD than are males (Haskell et al., 2010;Kessler, 1997Kessler, , 2003Kessler et al., 1993;Kessler et al., 1995), that there are basal sex differences in susceptibility to social stress in animals models (Bath and Johnston, 2007;Huhman et al., 2003;Trainor et al., 2011), and that there is already evidence that SSRIs can alter social behaviors in a sex-dependent manner (Greenberg et al., 2014;Terranova et al., 2016). ...
Most studies investigating the effects of acute administration of selective serotonin reuptake inhibitors (SSRI) on responses to social stress have been conducted with males. This is despite the fact that SSRIs remain the primary pharmacotherapy for social stress-related disorders for both sexes and that the prevalence of these disorders is twofold higher in women than in men. To determine whether acute treatment with the SSRI, fluoxetine, alters behavioral responses to social defeat stress in a sex- or social stress-dependent manner, male and female Syrian hamsters were subjected to one of three social defeat conditions: no defeat (placed into an empty resident aggressor (RA) cage), a single defeat by one RA for 15 min, or three consecutive defeats using different RAs for 5 min each. The day following social defeat, subjects were infused with either vehicle or fluoxetine (20 mg/kg, I.P.) 2 h prior to a 5 min social avoidance test. Overall, we found that fluoxetine increased social vigilance regardless of sex or defeat condition. We also found that fluoxetine affected social avoidance in a sex by stress intensity interaction, such that fluoxetine increased avoidance in no defeat males and in males defeated once but significantly increased avoidance in females only after three defeats. These data suggest that treatment with an SSRI could initially exacerbate the effects of social stress in both sexes. These data also emphasize the importance of including sex as a biological variable when investigating the efficacy of pharmacotherapy for stress-related disorders.
... This species is known for its relatively intense aggressive behavior (Johnston 1975). Originating in the far western regions of Asia (Siegel 1985) Syrian hamsters are solitary, with females engaging in offspring care alone without interacting with a mate (Gattermann et al. 2001). This social organization likely contributes to a reduced impact of social isolation on behavior in this species (Ross et al. 2017). ...
Social stressors are known to have strong negative impacts on mental health. There is a long history of preclinical social defeat stress studies in rodents focusing on males that has produced important insights into the neural mechanisms that modulate depression- and anxiety-related behavior. Despite these impressive results, a historical weakness of rodent social stress models has been an under-representation of studies in females. This is problematic because rates of depression and anxiety are higher in women versus men. Recently there has been a surge of interest in adapting social stress methods for female rodents. Here we review new rodent models that have investigated numerous facets of social stress in females. The different models have different strengths and weaknesses, with some model systems having stronger ethological validity with other models having better access to molecular tools to manipulate neural circuits. Continued use and refinement of these complementary models will be critical for addressing gaps in understanding the function of neural circuits modulating depression- and anxiety-related behavior in females.
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.
Syrian hamsters are a valuable, if underused, model system for studying the neurobiology of aggression. Male and female hamsters live in fields where they defend territories surrounding their individual burrows. With repeated aggressive experience, hamsters show an escalation of aggression as measured by a reduction in the time to initiate an attack. In contrast, defeated hamsters develop passivity and subordination. Both the escalation of aggression and development of submission activate the mesolimbic system, though through different circuits. Plasticity in the mesolimbic system mediates these changes in behavior, engaging synaptic transmission via both classic neurotransmitters and neuropeptides. At the same time that both male and female hamsters engage in territorial defense and aggression, there are sex differences in the underlying neurobiological control. These characteristics of hamsters make them an ideal model for studying normal and pathological aggression, along with developing therapeutics to treat pathological aggression separately in males and females.
In this chapter, the diversity of heterotherms, where they live and how they differ from each other is covered in detail. When data from free-ranging animals were available these were used preferentially, but information on captive animals is also included. As the extent of available data differs substantially among taxa, the information provided reflects what is known about a specific group to a large extent. To put the information on heterothermic endotherms into context with other organisms, I will address terrestrial ectotherms first.
Common medical problems diagnosed and treated in individual companion exotic mammals are relevant in a herd-health setting. Many of these problems are often associated with poor husbandry and/or inappropriate nutrition. Rabbits, ferrets, chinchillas, and rodents have been domesticated alongside humans and an understanding of their ethology gives veterinarians a base knowledge in making recommendations for animals in their care. This article briefly reviews the ethology and husbandry in such species, but detailed needs are beyond the scope of this article.
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In this study, Mesocricetus auratus is reported from one locality and Mesocricetus brandti from fifteen localities in Asiatic Turkey. The shape of the posterior margin of the palatine distinguishes M. auratus from M. brandti. The karyotype of M. auratus consists of 2n = 44, NF = 82 and NFa = 78. The diploid number of chromosomes was found to be 42 for M. brandti, with two different fundamental numbers, NF = 84, NFa = 80 and NF = 82, NFa = 78.
In most research involving Syrian golden hamsters, the species is used as an animal model or “subject” and as such is totally unidimensional. There is no consideration of its evolution, of its domestication history, or of its ecology and ethology; nor is there any obvious need for these factors to be considered. We know that the hamster comes from the breeder, or comes from a cage, and that is enough. This situation was indeed the way in which I first encountered the hamster, but I soon found the relationship to be incomplete. My search for the real hamster began after my first talk at a scientific convention when I was “informed” by a member of the audience that the hamster was a cross between a rat and a guinea pig, and although there were many doubts expressed, neither I nor any other of those present were confident enough to challenge this absurd hybrid notion.
by Alex. Russell. Vol. 1: xxiv, 446, xxiii p., 5 leaves of plates (4 folded) ; v. 2: vii, 430, xxxiv p., 15 leaves of plates (2 folded). Errata: v. 1, p. xxv (second set) ; v. 2, last leaf. Goldsmiths'-Kress no. 15930. Includes bibliographical references and index.