In 2014, researchers in French Polynesia spotted a bottlenose dolphin caring for a strange-looking smaller creature that they originally believed was the dolphin's offspring. Upon further investigation, the researchers discovered that the creature was actually a melon-headed whale. They discovered this after comparing the bottlenose mother's long narrow beak with the whale's short and blunt snout.
“We were really excited to be able to witness such a rare phenomenon,” says study lead author Pamela Carzon, scientific leader of the Groupe d’Étude des Mammifères Marins (GEMM) de Polynésie, based in Tiputa, French Polynesia.
Adoption in the animal kingdom typically occurs between related animals of the same species and genus, with the only recorded case of interspecies adoption happened in 2006, when University of São Paulo primatologist Patrícia Izar observed a group of capuchins caring for a baby marmoset. “At the time, we were really, really astonished,” she says.
The integration process into the bottlenose dolphin famiily was long and challenging. The whale had to learn bottlenose habits to fit in better with their adopted family, and would occasionally push his adopted sister out of the way to get preferential treatment from their mother. The mother was seen nursing the whale, which indicated to the scientists that she was invested in the bonding, too. Eventually the whale would act like the other young dolphins in the group, playing in the waves and leaping out of the water.
Scientists continue to speculate on the adoption, but one theory is that this particular bottlenose dolphin is a very tolerant creature. It was already accepting of scuba divers sharing her water, unlike many bottlenose dolphins who typically display aggressive behaviors to other species in their vicinity.
For more, check out the video below.