Small mammals

Identification

European ground squirrel/ or hereafter souslik (Spermophilus citellus) is a medium-sized ground squirrel, with a round body, short tail (20–40% of length of head and body), and reduced outer ears (Fig. 1). Head is convex in profile with large eyes (about 8 mm in diameter) and short vibrissae. The mass is 200-300 g, maximum 500 for the adult males before hibernation.
 

Biology

Reproduction in Spermophilus citellus is constrained by hibernation, limiting the timing of mating and on ground activity. Females deliver only 1 litter annually with litter sizes at emergence from natal burrows ranging from 2 to 11 young/litter. Gestation period for Spermophilus citellus is on average 29 days in the field. Juveniles 1st emerged from their burrows at 25 days of age. Juveniles remain in their natal burrow for about 1 month, and weaning begins in mid-June depending on litter size and maternal condition. The European ground squirrel dig simple temporary shelters and sophisticated underground systems with multiple exists and chambers that could be up to 2 meters deep and 3 meters long. They are obligatory hibernators and spend 5 to 8 (in the mountains) months in the year inactive. During the hierbanation their body temperature could be close to 0 degree. The European ground squirrel is active during the day. It feed manly on seeds and on leaves and small invertebrates in spring.
 

Distribution

Endemic to Central and Southeastern Europe, the range of Spermophilus citellus is disjunct, the Carpathians divide the range into 2 portions. The northwestern portion extends through the lowlands of the Czech Republic, Austria, Hungary, Slovakia, Serbia (to the north of Danube and Sava), and eastern Romania. The southeastern portion extends from eastern Serbia, Macedonia, and northern Greece through Bulgaria to Turkish Thrace, southern and eastern Romania, Moldova, and Ukraine. Extinct in Germany, Poland, and Croatia, the western margin of its distribution is in the Czech Republic. Nonetheless, the species was successfully reintroduced in Poland.
In Bulgaria the species is inhabits well maintained pastures and meadows from sea level to 2600 m above sea level. Here is located the highest known colony of the species - in the vicinity of Belmeken Peak in Rila National Park.
 

Identification

Medium-sized rodent, with a very short tail and contrasting variegated color. He has a black spot on his chest. On the sides of the cheeks there is a black hair band (from the bottom up to the neck) on both sides, on which are pronounced golden-yellow belts. The color on the back is grayish-ocher-brown, and on the abdomen - light ash-gray. The color of the side of the body is even lighter.
 

Biology

Very little is known about the species’ biology, because of its very limited range covering only parts of Bulgaria and Romania. Detailed and exhaustive studies have not been done until now.It lives alone in its own system of passages, with a depth of up to 1,5 m, the nesting chamber is 50-60 cm under the surface. There are a vertical and inclined tunnel from the chamber to the surface. The Romanian hamster is active mainly during the night. It is not an obligatory hibernator and the hibernation depends on the ecological conditions, the temperature and the population density. It feeds on green parts of plants, roots, seeds and fruits. Сtocks of crop seeds - corn, sunflower, wheat - as well as wild plants were found in the storage chambers. It breeds during the warm period of the year. One female gives 2 to 3 liters per year, each with 2-10 young.
 

Distribution

The Romanian hamster inhabits agricultural land mainly celeriac, alfalfa and cereals. It is endemic of Europe occurring only in Bulgaria and Romania. Most of the localities of this species in Bulgaria are found in middle and eastern part of the Danube Plain. In Romania it can be found in the south-eastern part of the country.