The European ground squirrel also known as the European souslik, is a species from the squirrel family, Sciuridae. It and the speckled ground squirrel are the only European representatives of the genus Spermophilus. Like all squirrels, it is a member of the rodent order. It is to be found throughout eastern Europe from southern Ukraine, to Asia Minor, Austria, the Czech Republic, Slovakia, Serbia, Greece, Romania, Bulgaria, Macedonia and north as far as Poland but the range is divided in two parts by the Carpathian Mountains.
The European ground squirrel grows to a length of approximately 20 cm (8 in) and a weight of approximately 300 grams (11 oz). It is a diurnal animal, living in colonies of individual burrows in pastures or grassy embankments. The squirrels emerge during the day to feed upon seeds, plant shoots and roots or flightless invertebrates. The colonies maintain sentinels who whistle at the sight of a predator, bringing the pack scurrying back to safety.
Breeding takes place in early summer when a single litter of five to eight young is borne. The European ground squirrel hibernates between autumn and March, the length of time depending on the climate. In preparation they will build up reserves of brown fat during the late summer.
The European ground squirrel is about the size of a brown rat, with an adult measuring 20 to 23 cm (8 to 9 in) and a weight of 240 to 340 g (8.5 to 12.0 oz). It has a slender build with a short bushy tail. The short dense fur is yellowish-grey, tinged with red, with a few indistinct pale and dark spots on the back. The underside is pale with a sandy-coloured abdomen. The large dark eyes are placed high on the head and the small, rounded ears are hidden in the fur. The dental formula is 1/1, 0/0, 2/1, 3/3. The legs are powerful with sharp claws well adapted for digging. Males are slightly larger than females otherwise they look alike.
The European ground squirrel has a shrill alarm call that will cause all other individuals in the vicinity to dive for cover. It also makes various soft chirruping and growling noises.
The European ground squirrel could be confused with the speckled ground squirrel which occurs in Poland (Lublin Voivodeship), Romania, Russia, Belarus and Ukraine, but that species has dark brown fur spotted with white and a thin tail and lives in areas with coarser vegetation. European ground squirrel is a colonial animal and is mainly diurnal. It excavates a branching system of tunnels up to 2 metres (6 ft 7 in) deep with several entrances. At other places in the home range it digs unbranched bolt holes in which to hide if danger threatens. If alarmed it emits a piercing whistle and when it is out in the open it often sits upright and looks around for predators. These include the weasel, fox, domestic cat and some species of birds of prey. It feeds on grasses, other plants, flowers, seeds, cultivated crops, insects and occasionally the eggs of ground nesting birds or their chicks. A study in Bulgaria found that the squirrel spent about eleven hours a day outside its burrow in mid-summer but by early autumn this has reduced to seven hours. Rather over half of the day was spent foraging but other activities observed included exploration, running, sitting, grooming, digging, scent marking and vigilance. During the winter it stops up the entrances to its burrow and hibernates in a nest of dry vegetation. Each individual occupies a separate chamber and during this period, the body temperature drops to 2.0 °C (36 °F), and the heart rate slows to a few beats per minute. During hibernation, the squirrel may wake up briefly for a few days and uses up the fat reserves accumulated during the summer, consuming about 90% of the fat stored in the body. In Bulgaria hibernation lasts from September to March.
(lat. Spermophilus citellus)