Yulilia eggs are commonly found half buried in snowdrifts. Unlike most eggs Yulilia eggs need cooler temperatures in order to hatch. The wooly ruff ensures that the egg does not freeze to the snow as it incubates.
Yulilias are a strictly outdoor species. Yulilias refuse to enter buildings and will put up a fight if forced. Yulilias are uniquely suited to living a life outdoors in Ark's coldest climes. Their blood contains a chemical similar to anti-freeze that keeps them from freezing in even the coldest of weather. The wooly ruff on a Yulilia's back not only traps heat close to the body but also doubles as camouflage, helping the Yulilia blend into the snow.
Groups of Yulilia will create a series of interconnected burrows dug into packed snowdrifts that function like small towns.