The European ground squirrel, also known as the souslik (Spermophilus citellus), has a voracious appetite for veggies. At least 80 percent of its diet is composed of the flowers, leaves, fruits, and seedlings of various grasses and forbs, including this Papaver rhoeas poppy near Hungary’s Balaton Lake, central Europe’s largest body of freshwater. Still, its palate is more cosmopolitan than you might expect. Despite the rodent’s penchant for herbs and diminutive size—just 7 to 9.5 inches in length—it also devours northern white-breasted hedgehogs, common voles and shrews, and the eggs and hatchlings of ground-nesting birds. Building a solid fat store is critically important to sousliks, as they spend August through March hibernating underground, burning through as much as 90 percent of their reserves. And when they emerge from their long torpor for spring mating season, males in particular spend loads of energy on chases and savage fights with their competitors.

Perhaps unsurprisingly, sousliks aren’t considered particularly sociable rodents. Though they live in colonies, each individual keeps to its own burrow system, which tends to be scented with noticeably odorous excretions from the creature’s three anal glands. Sousliks evade predators like whip snakes and weasels in part by piling heaps of soil in their tunnel entrances, which they dig through and rebuild each time they enter and exit. Despite their antisocial tendencies, they’ve also developed remarkable vocal adaptations to alert one another to danger. Of their eight distinct types of calls—screams, chatters, chirrs, and grunts among them—alarm calls are the most common. These contain enough variation to convey information about the individual sounding the warning—a sort of rodent caller ID—as well as the credibility and gravity of the potential threat.

The souslik’s tenacity has not saved it from an ignoble fate, however. In 2020, the International Union for Conservation of Nature declared the species endangered throughout its range in central and southeastern Europe, which extends from Poland, Germany, and Austria in the north to Bulgaria and parts of Turkey in the south. Sousliks likely spread across this area about 5,000 years ago, as Neolithic agriculture defoliated the largely forested continent, creating more of the short-grass fields, pastures, and meadows the animals prefer.

Ironically, intensified farming of monoculture crops is among the reasons for their modern decline. Sousliks have also struggled as brush and trees have reclaimed abandoned pastures, and as urban and suburban development has fragmented and eliminated other habitats. And as their numbers have dropped, so too have those of some species that depend on them for food, including the now endangered saker falcon (Falco cherrug) and vulnerable imperial eagle (Aquila heliaca) in Bulgaria, Romania, Ukraine, and Slovakia. The rodents are now considered extinct in both Croatia and Germany.

Fortunately, conservation efforts have born some fruit. Over the past 30 years, for example, numerous countries have translocated thousands of wild sousliks to help them re-occupy suitable habitat. Those that employed artificially drilled burrows or enclosures that provided the animals with sufficient shelter early on had the most success. Such efforts have helped the rodent regain its feet at least in Poland, where it had been extinct since the early 1980s.