Do monkeys know how to give CPR?

That's the question circulating on the Internet this week, after a video depicting one monkey apparently saving the life of another after an accident at an Indian train station went viral.

The footage, posted this week by YouTube user gadhamasti, shows an unconscious monkey that was apparently shocked by wires at a busy train station in the industrial city of Kanpur in northern India. A male companion monkey is then seen apparently trying to revive his comrade.

The monkey bites and drags the limp animal and even douses it in water. After about 20 minutes, the injured monkey revives.

Luisa Arnedo, a National Geographic grants program officer who earned her Ph.D. studying primates, says the animals in the video are rhesus macaques, which are native to India and much of Asia and are frequently seen in cities. (Learn about rescue of injured rhesus macaques.)

Acknowledging Death?

Arnedo adds that there is little research into how nonhuman primates deal with death since the events are seldom observed. However, scientists have occasionally seen primates react to death, "in many cases by shaking the body of the dead animal, as not accepting its immobility, and also reacting by rough behaviors seemingly aimed at reanimation." (See a video about rhesus society.)

Chimpanzees have been seen becoming very quiet when a member of their group dies, especially if it is a high-ranking individual, Arnedo adds. And primate mothers will sometimes carry the mummified bodies of their babies for weeks or even months, "as if denying the loss of their baby."

It's unclear whether these behaviors are intentional, Arnedo says.

"In this particular case, does the male shaking the body of the injured individual know that by shaking it and dropping it in water, it can reanimate it?" she asks. It's difficult to say.

Arnedo calls the video "an amazing representation of the complexity of primate behavior," and says "it is a reminder of how much we still don't understand about their societies and their reactions, and how much is left to do for those studying primates." (See "Macaque on a Hot Tin Roof: Mount Popa, Myanmar.")