An eight-year-old boy, Dante de Kort, spotted a dead collared peccary near his home in central Arizona in January. The fourth-grader set up a motion-activated camera — a birthday present from his grandparents — next to the corpse to film it for a science fair project, presumably to capture a scavenging predator.

But what his camera captured has led to interesting findings about the social life of peccaries. The video captured the peccary’s herd members walking up to the corpse and seemingly mourn the loss.

Peccaries, commonly referred to as javelinas or skunk pigs, are mammals native to the Americas and are pig-like in appearance. They are known to be highly social and they live in groups and rely on their social structure to defend their territory, protect against predators and interact much like a wolf pack.

The video shows other members of the herd visiting the carcass of the dead female peccary. They were repeatedly trying to push and turn the carcass with their snouts and mouth. Some herd members slept next to the body at night to protect it from predators. 

Prescott College biologist Mariana Altrichter, who is also chair of the International Union for Conservation of Nature's Peccary Specialist Group, said she came across the video while visiting a regional science fair and was surprised to notice this particular behavior.

The footage was amazing, she said in a National Geographic article. The fact that the animals revisited their peer for 10 days caught her eye, which motivated her to study this behavior further. She published a paper on the behavioral reactions of peccaries toward a dead herd member in the journal Ethology on 5 Dec.

According to the study, peccaries do react to the death of a herd member by behaving in particular ways. The peccaries even protected the carcass from many coyotes throughout the night while being outnumbered. This risky behavior shows the deep bonds between the members of a herd as not many animals would risk their lives to defend a dead member of their pack.

Grief is not an emotion restricted to humans. It is well documented that elephants mourn the loss of a herd member. They have been spotted standing over the dead body, rocking it back and forth and even trying to pull it. Other large brained animals like chimpanzees and dolphins also mourn the loss of a loved one. Even horses exhibit a visible change in behavior after the loss of a companion. They start refusing food and companionship for days.

Experts claim that animals exhibit certain behavior that can be attributed to grief. But it was not clear if the peccaries were actually distressed or not.

"The strongest evidence for grief was the act of sleeping beside the body — a behavior that can’t simply be chalked up to curiosity, territoriality, or other alternatives. It's quite plausible that peccaries would grieve, given the growing body of research detailing animals’ emotional responses to death," Barbara J. King, an emeritus professor of Anthropology at the College of William and Mary said.