Mourning behaviors in social animals
Dolphins are joining the list of animals that display mourning behaviors, having been observed carrying the body of a recently deceased calf. Two other corpses were found to show signs that this ritual may have lasted up to 30 minutes on each occasion, with an adult using it’s head and back to transport the body.
While we can’t responsibly attribute motivation to the dolphins, since we can’t assume they even have a proxy for grief, it seems pretty clear that this is deliberate and specific behavior. Dolphins don’t normally “carry” each other like this, and it’s hard to imagine that the effort involved was in any way offering the adult any form of protection, nutrition, etc. The purpose appears to be entirely tied to marking the loss of a family member.
It’s not surprising that dolphins are turning up on the list of animal mourners. Other members include elephants and sea lions, both of which have strong family bonds that last a lifetime, at least for females (do walruses or elephant seals do this to?) These animals generally live in matrilineal, multi-generational families, so the loss of a family member could easily be a significant event to the survivors, even if just on the practical level of losing their assistance in protecting the group, raising young, etc.
Source: These Dolphins Mourn Their Dead by Erin Blakemore, Smithsonian.com