According to a new study, marine mammals mourn the loss of friends and family, just like humans. As part of the research, scientists have come across seven species of dolphins and whales that keep vigil, and even keen, over the dead. While the exact cause for such behavior is not yet known, the researchers believe that the sea creatures might be grieving the death of companions.
Recently published in the Journal of Mammalogy, the study is based on observations from 14 different occasions. The organisms exhibiting this fascinating behavior include the spinner dolphins (or Stenella longirostris), Indo-Pacific bottlenose dolphins (Tursiops aduncus), short-finned pilot whales (Globicephala macrorhynchus), killer whales (Orcinus orca), sperm whales (or Physeter macrocephalus), Australian humpback dolphins (Sousa sahulensis) and lastly Risso’s dolphins (Grampus griseus). Speaking about the find, the team from Italy’s University of Milano-Bicocca stated:
The present study helps to corroborate that adults mourning their dead young is a common and globally widespread behavior in long-lived and highly sociable/cohesive species of mammals.
As the scientists point out, keening or keeping vigil over the deceased is likely a costly and time-consuming affair in the animal world. It keeps them away from other crucial tasks, such as mating, finding food as well as socializing with other living creatures. The practice therefore seems unnecessary, especially from the evolutionary point of view. Melissa Reggente, the paper’s co-author, explained:
We found it is very common, and [there is] a worldwide distribution of this behavior. They are in pain and stressed. They know something is wrong.
Although the act itself is quite common among marine mammals, each species was found to grieve differently. While exploring the Red Sea, the team stumbled across an Indo-Pacific bottlenose dolphin carrying a smaller, dead dolphin on its fin. During another occasion, the researchers observed a killer whale, named L72, carrying its dead newborn by holding it in its mouth. Robin Baird, a scientist at Washington-based Cascadia Research Collective, said:
She was trying to keep the [dead] calf up at the surface the entire time, balancing it on top of her head… The animals go through a period where they’re experiencing the same kind of emotions you or I would when a loved one dies.
According to the scientists, certain species of these sea mammals were also found to pet their departed companions using their fins, enclosing them in a sort of protective circle. The team, however, will have to substantiate their research with further studies.
Via: National Geographic