Do dolphins grieve for their dead?


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A series of studies on dolphins and whales has raised questions as to whether cetaceans might mourn the death of a family member and experience grief.

A team of Earthwatch Institute volunteers and their supervisor have been observing Bottlenose dolphins in western Greece and have observed what looks like different reactions to death depending on whether the pod member died suddenly or after a long period of illness.

Joan Gonzalvo from the Tethys Research Institute and his team have observed Bottlenose dolphins in the Amvrakikos gulf for the last five years. In July 2007 they witnessed a mother repeatedly lifting her dead newborn calf to the surface in what appeared to be an attempt to get it to breathe.

The calf had a large bruise on its lower jaw suggesting that it may have been killed by another dolphin. The mother continued this action, calling to and touching her dead calf over a period of two days.

Gonzalvo theorises that the mother may have been mourning the sudden death and appeared unable to accept it.

On a separate occasion in 2008 the researchers came across a pod surrounding a 2-3 month old dolphin that had a number of bleach marks and was struggling to swim. The pod appeared stressed and were swimming erratically but when the dolphin died an hour later they left the dolphin to sink.

Gozalvo said: "My hypothesis is that the sick animal was kept company and given support, and when it died the group had done their job. In this case they had already assumed death would eventually come - they were prepared."

Ingrid Visser of the Orca Research Trust in New Zealand, has seen similar behaviours in both Bottlenose dolphins and Orcas where they carry dead infants and appear to be in mourning. She says in New Scientist,  that although this may simply be a case of the animals not realising that their pod member is dead, "…we do know that cetaceans have von Economo neurons, which have been associated with grief in humans."

As a result, she speculates that the behaviours are a form of grief.

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