News has surfaced from New Zealand this month of an unusual interspecies occurrence. A female bottlenose dolphin has been found to have seemingly adopted a very young pilot whale calf. Although unusual, this is not the first reported case of interspecies adoptions, and we will cover some other known cases of cetacean species picking up members from another kind. Interestingly though, bottlenose dolphins seem to be quite big culprits in these cases!
Bottlenose dolphin and pilot whale
In the Bay of Islands, off northern New Zealand, the bottlenose dolphin and pilot whale pair have been observed on two separate occasions, five weeks apart. It is thought that the mother may have lost her own calf and has potentially kidnapped the offspring of a pilot whale mother. Whilst it isn’t unheard of for dolphin mothers to steal babies from others, it is unusual for dolphins to adopt from a species that is significantly larger than them. Most adoptions are only temporary, and it is hoped the pilot whale calf will be reunited with its actual mother. Otherwise the dolphin and pilot whale are likely to separate after the weaning stage due to their differing diets, as pilot whales like to feed on squid at night.
Belugas and narwhal
Reported in 2018, researchers in Quebec’s St Lawrence River discovered a male juvenile narwhal 1000km far from its home in the Arctic, under the care of its cousins, the belugas. Belugas and narwhals can both be found in the Arctic, however they don’t typically interact due to having different hunting and ranging habits. However, one particular narwhal seemed to have got lost and been adopted by a group of male belugas that treat him as one of their own. They take part in play and sexual games with one another, suggesting the narwhal is fully accepted, therefore he may remain with this group long-term, as he’s so far from his normal home.
Bottlenose dolphin and melon-headed whale
Back to our bottlenose dolphin friends again, a unique trio were observed in Rangiroa atoll in French Polynesia in 2014 of a mother, her calf and a second, much darker calf – a melon-headed whale. What makes this story so interesting is that dolphin mothers will typically steal babies when they’ve lost their own, however this mother still had her offspring and had picked up a non-related calf to add to her clan. The little melon-headed calf was discovered to be a male, and to also be nursing from the mother, alongside its ‘sibling’. The melon-headed whale lived with the bottlenose mother for almost three years and even picked up dolphin behaviours, such as surfing. Sadly the commitment of the dolphin mother to the melon-headed calf may have caused the demise of her own calf, who disappeared at a year and a half old.
Sperm whales and bottlenose dolphin
A different story of friendship rather than adoption is the case of a group of sperm whales interacting with an adult male bottlenose dolphin off the Azores – however this was no usual dolphin. The male bottlenose had a spinal deformity, and had likely been rejected by his group for this reason. What also makes this interaction unique is that sperm whales are not typically known to forge bonds with other species, therefore this particularly group must have made an exception to this adult dolphin due to his disability. The dolphin was seen nuzzling and rubbing against the group members whilst travelling, which was also reciprocated. The interaction was observed over an eight day period, however may have continued for longer out of sight of human eyes.
Bottlenose dolphin and common dolphin
In another Bay of Islands, New Zealand adoption story, those bottlenose dolphins are at it again – this time with an abandoned common dolphin calf. Bottlenose dolphin mum (Kiwi) took on Pee-Wee as one of her own, allowing the common dolphin calf to nurse from her, despite Kiwi not mothering a calf of her own in 5 years. This is just one example of one of the amazing things that dolphins can do – lactation on demand!
Bottlenose dolphin and spinner dolphin (and Fraser’s dolphin)
Another return to an area of serial adopters, the bottlenose dolphins of Rangiroa atoll have been documented adopting more than just the melon-headed whale. A newborn spinner dolphin found its way into a bottlenose dolphin group, however this time to an adoptive father! Over the years, a juvenile spinner was also seen associating with a particular female bottlenose dolphin however it was never confirmed whether it was the same individual. The bottlenose dolphins of that region were also seen with a newborn Fraser’s dolphin.
Sherie Feature Blogger Sea Watch Foundation Intern
Sources
- Bottlenose dolphin adopts pilot whale calf
- Size Doesn’t Matter to a Dolphin Mom As She Adopts a Whale Calf
- ‘One of the boys’: lost narwhal finds new home with band of beluga whales
- Bottlenose Dolphin Adopts Whale Calf of Another Species, The Scientist
- https://www.nationalgeographic.com/animals/article/bottlenose-dolphins-adoption-oceans-calves
- Dolphin adopts baby whale in ‘astonishing’ first known case
- Deformed, lonely dolphin adopted by friendly sperm whales
- Deformed Dolphin Accepted Into New Family
- Dolphin adopts calf of another species
