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Fishermen caught an ultra rare two-headed porpoise and… threw it back in

A group of Dutch fisherman caught an ultra rare two-headed porpoise off the coast of the Netherlands last month.

But after taking a few shots of the incredible creature, a conjoined twin harbour porpoise (Phocoena phocoena), the fishermen did not turn the creature over to science, instead tossing it back into the ocean.

To be fair, the porpoise was dead, and the fishermen thought that it would be illegal to keep it. Thankfully, they snapped a few photos of the rare beast, which has been now confirmed as the first documented case of conjoined twin harbour porpoises ever.

The Washington Post reports that photos of the porpoise eventually ended up with Erwin Kompanje, who is the curator of mammals at the Natural History Museum in Rotterdam.

Keen to get that porpoise into the lab, Kompanje was crushed to find out that the fishermen had thrown it back in.

Kompanje, who has studied cetaceans (whales, dolphins and porpoises) for 20 years told The Washington Post that there had only been nine other cases of conjoined cetaceans before.

The conjoined porpoises were both male and would have died soon after birth. The most likely cause of death would have been either drowning caused by the brains telling the creature to swim different directions or the single heart’s inability to pump enough blood, according to Kompanje.

Although Kompanje would have loved to have gotten his hands on the unfortunate porpoise, using the photos he was able to co-author a paper published in Deinsea this month.

The exact cause of the conjoining is unclear, but in his paper, Kompanje writes that it was most probably the result of secondary fusion of two originally separate embryonic discs or a zygote that only partially split during the early stages of development.

Kompanje told New Scientist that even normal twinning is extremely rare in cetaceans.

“There is simply not enough room in the body of the female to give room to more than one fetus,” he said.

In humans, conjoined twins are also extremely rare and occur about once every 200,000 live births. Approximately 40 to 60 percent of conjoined twins arrive stillborn and about 35 percent survive only one day according to the University of Maryland Medical Centre.

About the author

Stefan is an Adelaide-based freelance writer. In his spare time, he plays tennis badly, collects vinyl and brushes up on his Mandarin. Follow Stefan on Twitter

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