Bottlenose Dolphin with Deformed Spine ‘Adopted’ by a Pod of Sperm Whales : The World We Share

When you think about dolphins, you probably imagine highly social animals that enjoy basking in the lime light. For the most part, you’d be right. Sperm whales, on the other hand, tend to be on the opposite end of the socialization spectrum; they’re shy, reserved, and they rarely mingle with other sea creatures.

Given the nature of these two animal species, it’s not hard to understand why marine life experts were so shocked when they discovered a bottlenose swimming along with a pod of sperm whales. Generally, when sperm whales and bottlenose dolphins are seen together, it’s because the dolphins are chasing and harassing the whales and their calves. But in this instance, the interaction painted a very different picture of a very different relationship between the pod and the lone dolphin calf.

Alexander D. M. Wilson / Aquatic Mammals

“It really looked like they had accepted the dolphin for whatever reason,” behavior ecologist Alexander Wilson, who has co-authored an upcoming paper about the rare encounter for the journal Aquatic Mammals, told Today. “They were being very sociable.”

“Sociable” may even be an understatement. Not only was the dolphin calf swimming along with the sperm whales, over the eight day period in which experts observed them, the whales were nuzzling with the dolphin, as if it had been adopted by the pod.

ScienceNOW reported that the dolphin had a rare spinal deformity that may have kept it from being able to keep up with its own kind. It is speculated that this may be part of the reason that the dolphin chose to follow the sperm whale pod, since sperm whales tend to be much slower than bottlenose dolphin. But experts are still perplexed as to why the sperm whales would actually be willing to accept the dolphin, even if it were for a short period of time. There doesn’t appear to be anything for the whales to gain from the relationship, yet they seemed to have accepted the dolphin, wholeheartedly, into their little circle.

“Why would sperm whales accept this animal in their group?” Ecologist Monica Almeida e Silva told ScienceNow. “It’s really puzzling to me.”

Behavioral biologist, Luke Rendell of the University of St. Andrews in the United Kingdome says it may be best to not “overread” the whales’ motivations as pity for the dolphin. Rather, he told ScienceNow that they may have simply enjoyed the type of attention they’ve received from the dolphin, or “they could just be thinking, ‘Wow, this is a weird kind of calf.’”