經過三年的追蹤，科學家發現太平洋一隻已育有一隻幼兒的雌性寬吻海豚，竟收養了一隻瓜頭鯨孤兒！對於哺乳類動物乳汁是非常寶貴，所以收養行為非常罕見，這次亦是首次發現海豚有此行為，而且是跨物種的。

after tracking for over three years in French Polynesia, researchers found that a female bottlenose dolphin has adopted an orphan melon-headed whale calf and raises together with her own calf. milk is very precious resource for mammals, so adoptions is very rare. This is the first record of dolphins having this behavior, and is a cross-genus adoption as well.

https://www.sciencealert.com/for-the-first-time-scientists-have-seen-dolphins-adopting-the-orphaned-calf-of-another-species