Lying, sitting or standing: Resting postures determined by animals' size

Cows always lie on their chests so that their digestion is not impaired. Rodents sometimes rest sitting down, while kangaroos sometimes lie on their backs. The larger the animal, the less often it lies down, and when it does, it is more likely to lie on its side - but there are exceptions.

from Animals News -- ScienceDaily https://ift.tt/2OsG0oB