Two-headed mammals are an oddity, but it’s not something that’s completely unheard of.
It something we’ve seen multiple times on domesticated animals, but this porpoise is one of only 9 other reliably documented cases. This is the only documented case for this specific species, known as P. phocoena.
Fishermen plucked it out of the North Sea off the coast of Ireland recently. It was only discovered after it had died, after which the fishermen threw it back into the sea, fearing it would have been illegal to keep it.
They took some photos to hand over to researchers who might have some idea of how it happened. It’s too early for any in depth comment at this stage, but it does at least give researchers some quality photographic evidence to work with.
From these photographs they were able to tell that the conjoined porpoise had only 1 tail and dorsal fin, but 2 pectoral fins. Amazingly, it also had 2 fully developed heads, each with 2 eyes and blowholes.
According to experts who have seen the photos, the animal most likely died during birth.