Zurich, Switzerland – In the warm summer months, European ground squirrels, known as European sousliks, are especially active at Zoo Zurich, where a growing colony with newly born young is attracting attention for its fast-moving daily life.

The animals are strongly endangered and have only recently become part of the zoo’s residents. This year, they have produced young for the first time, adding further activity to the already lively group.

The young, born at the end of April, have recently emerged from their underground burrow system for the first time. They can now be observed daily in daylight as they move around the enclosure.

Their behaviour is constant and energetic. Some shift soil near burrow entrances, others gather grass, while others pause to scan the sky before continuing. Younger individuals sometimes compete with older ones for food, including beetroot pieces.

The colony is highly vocal, producing a range of sounds including chirps, grunts, and loud alarm calls. Eight different call types are currently known in the species.

European sousliks live in colonies but are not strongly social. Each animal occupies its own underground burrow, about 1.5 metres deep. The colony structure mainly serves protection from predators.

When danger is detected, the animal that spots it issues a warning call that can also indicate the level of threat.

The species is native to Central and Southern Europe, ranging from the Czech Republic to Turkey. It hibernates from October to March due to cold winters and limited food availability.

Its active period is short but intense. Males emerge first from hibernation, establish territories, and begin reproduction after restoring energy reserves. Females raise the young alone. After a gestation period of up to 28 days, 5 to 9 blind, hairless, and helpless young are born underground.

The young leave the burrow after about a month and become fully independent roughly three weeks later. By late summer, they focus on building fat reserves for winter and maintaining or expanding burrows.

The species faces serious threats, including habitat loss, population fragmentation, and climate change. It has already disappeared in countries such as Germany and Croatia, and further declines are expected in coming decades. It is currently listed as strongly endangered.

A reintroduction project in the Czech Republic offers some hope, and Zoo Zurich plans to take part in future conservation efforts.

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