The colonies maintain sentinels who whistle at the sight of a predator, bringing the pack scurrying back to safety.

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).

The large dark eyes are placed high on the head and the small, rounded ears are hidden in the fur.

[3] 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.

[6] Only when S. citelloides became extinct during the early Holocene was the European ground squirrel able to expand its range into Central Europe, possibly favoured by the clearing of vegetation provided by neolithic farmers and their lifestock.

[7] The European ground squirrel is native to central and southeastern Europe where its range is divided by the Carpathian Mountains.

These conditions are lost when changes in agricultural practice convert grassland into arable land and forest, or grazing ceases and the grass grows coarse and scrubland develops.

[1] Other places with short vegetation that sometimes provides suitable habitat are railway embankments and road cuttings and verges.

It feeds on grasses, other plants, flowers, seeds, cultivated crops, insects and occasionally the eggs of ground nesting birds or their chicks.

Rather over half of the day was spent foraging but other activities observed included exploration, running, sitting, grooming, digging, scent marking and vigilance.

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.