Rare intersex shark discovered off of Taiwan

Avatar By Joseph Scalise | 3 years ago

A group of researchers from Xiamen University have conducted an autopsy on a shark discovered off the coast of Taiwan that had both male and female reproductive organs, according to a new report published in the journal Marine and Coastal Fisheries

The species is a Pacific spadenose, and it had “claspers” — which made it look male on the outside — as well as ovotestes. It also had male and female reproductive systems. The ovotestes — which are intermediary between male and female — had viable eggs and sperm.

Intersex animals are born with genetics and physical characteristics that differ from the male/female binary. Some animals are hermaphroditic, and some change sex based on their environment, but those characteristics are distinctly different from intersex.

Scientists have documented intersexuality in a wide range of animal species, but this is the first time researchers have found an intersex Pacific spadenose. In addition, the specimen is rare because it had extremely well-formed and functional reproductive organs. Most intersex sharks have poorly formed organs.

While the discovery seems to be surprising, most sharks do not undergo autopsies. As a result, researchers have no bearing on how common intersexuality is among the fish. Though some sharks have been known to give virgin birth, that is not the same as being intersex. Even so, some researchers believe an intersex animal could give birth to live young.

“I’m not sure there is any solid biological evidence for that, but it is an interesting idea,” Chris Lowe, director of the California State University, Long Beach Shark Lab who was not involved in the study told Newsweek.

Although researchers are not sure what causes sharks to be intersexual, some believe it could be linked to climate shifts. However, genetic drivers and natural variation could play a large role as well. 

“Environmental contamination is certainly not the only reason why this might happen every now and then,” said Carl Meyer, a marine biologist at the University of Hawaii who was not involved in the study, according to International Business Times. “Purely genetic drivers could largely determine what happens during reproductive development. There could be a genetic miscoding that ends up with a rare intersex example in a species.”