National Geographic has a fascinating story where a bottlenose dolphin adopted a baby of a different species, a melon-head whale, back in 2014 and is still caring for it today.
The whale species are found throughout the tropics and are a close relative to pygmy whales and pilot whales according to Wiki.
The baby whale lives with a pod of 30 dolphins that frequent French-Polynesian waters. and has been taught to surf. How cool is that? Not everything is nirvana, however.
See the excellent read in the National Geographic link below.
Erica Tennenhouse writes in National Geographic:
Adoption is uncommon among wild mammals, with most occurring between related members of the same species. The only other scientifically documented case involving an adopted orphan of a different species and genus was 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.
Although the mother already had a baby, once the lone melon-headed calf entered the picture, he rarely left his new mom’s side. The trio were frequently seen swimming together—an unusual sight, as dolphin mothers normally care for a single infant at a time.It wasn’t always familial bliss—the melon-headed calf would repeatedly shove his adoptive “sister” out from her place under their mother’s abdomen.The ever-persistent orphan was not only intent on integrating himself into the family unit; he also figured out how to fit into the broader group of dolphins.
One possibility is that the recent birth of her calf triggered her maternal instincts. “Most likely, it was just a perfect moment for this calf to come along, when [the mother] was at a very receptive period to forming those bonds with her own offspring,” says MacLeod, “and it led to this slightly wacky situation.” (Failure to launch: Learn about animals that stay with their moms for years.)
So much more at National Geographic.
The baby whale lives with a pod of 30 dolphins and has learned to surf. Dolphins spend most of their time having fun.