Sperm Whales Adopt A Dolphin With Spine DeformityS

ScienceNow is reporting that marine biologists working in the Azorean archipelago of the Northern Atlantic have discovered a group of sperm whales who appear to have taken in an adult bottlenose dolphin who has a rather serious spinal malformation. And it wasn't just a one-time encounter for the two species; the dolphin appears to be sticking around.

Other than the 'S' shape curvature to its body, the dolphin appears to be healthy. The researchers have virtually no way of knowing if the deformity has anything to do with the unprecedented inter-species co-mingling — though they suspect that it does.

Dolphins are a hierarchical species, so they may have shunned this particular member on account of its serious birth defect. In the words of one of the researchers, Alexander Wilson, "It might be that this individual didn't fit in, so to speak, with its original group." Or maybe it just couldn't keep up. For now, however, this will all have to remain speculative thinking.

Chelsea Wald explains more:

Sperm Whales Adopt A Dolphin With Spine DeformityS

Among ocean-dwelling mammals, dolphins are perhaps the most gregarious. They've been spotted traveling, foraging, and playing with a wide variety of other animals, including many whales. On the other hand, as far as the authors of the forthcoming paper in Aquatic Mammals know, sperm whales had never been reported cozying up to another species. Specialized deep-water hunters who travel great distances, the whales are more timid than dolphins and harder for people to observe.

Indeed, behavioral ecologists Alexander Wilson and Jens Krause of the Leibniz-Institute of Freshwater Ecology and Inland Fisheries in Berlin did not expect to find a mixed-species group when they set out to observe sperm whales (Physeter macrocephalus) some 15 to 20 kilometers off the island of Pico in the Azores in 2011. But when they got there, they found not only a group that included several whale calves, but also an adult male bottlenose dolphin ( Tursiops truncatus). Over the next 8 days, they observed the dolphin six more times while it nuzzled and rubbed members of the group. The sperm whales seemed to at least tolerate it; at times, they reciprocated. "It really looked like they had accepted the dolphin for whatever reason," says Wilson, who was snorkeling nearby. "They were being very sociable."

Sperm Whales Adopt A Dolphin With Spine DeformityS

As to why the sperm whales took in the dolphin, the researchers aren't sure about that, either. But they warn against reading to much into it, saying that what looks to us like "pity" or compassion may be in fact something else entirely.

More here, including slideshow with more photos.

Images: ScienceNOW/Alexander D. M. Wilson/Aquatic Mammals