Intersex Shark Found in Taiwan Has Both Male and Female Sex Organs

Sandbar sharks swim around during a cageless shark dive tour in Haleiwa, Hawaii February 16, 2015. Reuters

When investigators opened up the carcass of a Pacific spadenose shark found off the coast of Taiwan, they were shocked to find the shark had both male and female reproductive organs.

In a report published in the journal Marine and Coastal Fisheries in September, scientists at Xiamen University in China documented the shark's anatomy. They found that it had "claspers," which made it look male on the outside, and ovotestes on the inside. It also had both male and female reproductive systems. The ovotestes, which are intermediary between male and female, had viable eggs and sperm, Hakai Magazine reported Wednesday.

This Galapagos shark is a species of "requiem shark," the same group that the Pacific spadenose shark belongs to. NOAA / Public Domain

This is the first time scientists have documented an intersex shark of this particular species. However, intersexuality has also appeared in other sharks and other animals, as well as humans.

Intersex animals are born with genetics and/or physical characteristics that differ from the male/female binary. Some animals are hermaphroditic and some change sex in certain environments, but those are distinct from intersex animals.

According to the Intersex Society of North America, determining the frequency of intersex humans can be complicated. However, they state "we do know that about 1 in 2,000 children is born with genitals that are pretty confusing to all the adults in the room." Globally, that makes intersex people more common than Jewish people.

The intersex Pacific spadenose was rare, not just in the fact that it was intersex, but that it had such well-formed and potentially functional reproductive organs. In other cases of intersex sharks, the gonads are usually small or malformed.

There is no central reporting agency for intersex fish, and most sharks do not undergo animal autopsies, so we don't really know how common intersexuality is among them.

Some sharks, along with some species of reptiles, fish and insects, have been observed giving virgin birth. However, those individuals weren't known to be intersex. While some sharks lay eggs, others deliver live young.

Could an animal with both male and female reproductive cells ever make its own babies? "I'm not sure there is any solid biological evidence for that, but it is an interesting idea," wrote Chris Lowe, director of the California State University, Long Beach Shark Lab, in an email to Newsweek.