It’s hard not to anthropomorphize your pets, especially when their eyes look so limpid and sad as they’re begging for treats. But it’s hard to tell whether animals, on average, experience the same range of emotions as their human counterparts. Feelings like contentment or discomfort tend to be relatively universal, but what about complicated ones like grief?

As SciShow host Michael Aranda explains in the video below, potential signs of grief—which some anthropologists define as "a change in behavior in living creatures that knew the deceased"—have been observed among some highly intelligent mammals. Elephants, for example, have gently caressed their dead or remained by their bodies for days. In some cases, they've even "buried" corpses, or carried them away for up to half a mile.

Meanwhile, captive chimps and monkeys either clam up or make noises of distress when their peers die. Dolphins aggressively defend their dead. And both lemurs and monkeys visit their deceased and emit cries, seemingly in sorrow.

Aranda describes other prospective signs of animal "mourning" (and also makes lions appear to be truly the most cold-hearted of mammals) in the video below.