Two-Headed Harbor Porpoise Appeared In The North Sea In Netherlands By partha das | Jun 16, 2017 09:26 AM EDT Fishermen caught a two-headed harbor porpoise in the North Sea in Netherlands. A confirmation assures that this is the first case of conjoined twin harbor porpoises. The sighting of the fully grown two-headed harbor porpoise is very rare. According to New Scientist, the recently surfaced conjoined twins must be the 10th known case in cetaceans. Cetaceans include whales, dolphins or porpoises. A study regarding the said harbor porpoise is available in the popular online Journal of the Natural History Museum Rotterdam, Deinsea. One of the key authors of the study, Erwin Kompanje, reveals that anatomy of the cetaceans is different from that of the terrestrial mammals. Not much information is available about the cetacean's adaptation for living as a mammal in the sea. But, this new case of the two-headed harbor porpoise must bring important information on this aspect. Watch video The two-headed harbor porpoise was probably dead when the fishermen caught the sea creature in the net in late May. The fishermen returned the harbor porpoise back into the North Sea as they thought it could be illegal to keep this specimen. Though, they took some images of this sea animal and produced them for further research work. This harbor porpoise is a baby male porpoise that had pectoral fins and fully grown body. The heads were also well-developed. According to Time, the sea animal weighed almost 13 pounds and had a length around 28 inches. Researchers did not have any clear idea about the age of the two-headed harbor porpoise, but they thought the sea creature died soon after birth. Erwin Kompanje uttered that they can't examine the two-headed harbor porpoise physically, but still they have the opportunity to learn more from the images. Kompanje also stated that the tail of the twins had not stiffened and it pointed out that the sea animal died soon after its birth. Twins are mainly visible in humans and other common domestic animals. But, it is rare in cetaceans, mainly in dolphins and whales. Kompanje revealed that a female harbor porpoise doesn't have sufficient space in the body to contain more than one fetus. Many other conjoined twins like the two-headed harbor porpoise may probably exist in the oceans. Though, people can't notice them as these sea creatures are born in the oceans and never surfaced.