Study shows cetaceans mourn their deceased young
A new study suggests that whales and dolphins grieve for their dead. Researchers looked at 14 documented cases of various species of cetaceans holding 'vigils' for deceased members of their pods and believe the only explanation is that it must be some form of mourning.
'The study helps to corroborate that adults mourning their dead young is a common and globally widespread behaviour in long-lived and highly sociable/cohesive species of mammals,' the researchers from the University of Milano-Bicocca in Italy wrote in the Journal of Mammalogy.
The study compiled observations from the cases which involved seven different marine mammals: Indo-Pacific bottlenose dolphins (Tursiops aduncus); spinner dolphins (Stenella longirostris); killer whales (Orcinus orca); Australian humpback dolphins (Sousa sahulensis); sperm whales (Physeter macrocephalus); Risso’s dolphins (Grampus griseus); and short-finned pilot whales (Globicephala macrorhynchus).
But although the behaviour was common, the way these animals grieve is varied. Scientists in the Red Sea observed an Indo-Pacific bottlenose dolphin push a smaller, deceased dolphin through the water on its fin. The dolphin was badly decayed and had probably been dead a while.
A killer whale, called L72, which had recently given birth, off San Juan Island, Washington,was seen carrying a dead newborn in her mouth.
'She was trying to keep the [dead] calf up at the surface the entire time, balancing it on top of her head," says study co-author Robin Baird from the Cascadia Research Collective in Olympia, Washington.
'The animals go through a period where they’re experiencing the same kind of emotions you or I would when a loved one dies.'
The study also found reports of ocean mammals touching the dead companions with their fins, and making a protective circle around an adult morning a dead calf.
Short-finned pilot whales spotted in the North Atlantic Ocean were seen carrying dead calves on four different occasions, the study said. Though surrounded by other whales, only one adult individual remained constantly in contact with the body, holding it in its mouth.