Stony Brook University Grad Student Studies Sawfish

Jun 7, 2015

Some animals can reproduce asexually- that is, by themselves. When they’re in captivity, or they can’t find a mate, some female snakes or frogs can impregnate themselves and give birth to babies without fathers. It’s rare in nature, and usually happens with smaller animals. But, for the first time, a scientist has found larger animals living in the wild that were born this way.

In fact, they’re 18-foot long sawfish, with long noses like chainsaws and bodies like sharks. They live in the muddy rivers of south Florida, and they’re critically endangered.

Andrew Fields, a Ph.D. student at Stony Brook University’s School of Marine and Atmospheric Sciences on Long Island, was studying DNA samples of these fish in the lab, when he realized that, based on their genes, a few of them had to be the children of mothers who reproduced asexually.

“They looked like regular sawfish. They acted like regular sawfish. But the genes tell a different story,” he said.

Fields said it usually only happens when animals are in captivity, or their numbers are so low they can’t find a male to mate with. He said they’re probably not choosing to do this.

“And this is could be one of those big warning signs to say, hey, this is an endangered species. It really needs to be protected right now," he said. "They can’t find mates, which means that they’re on their way out.”

The next question, Fields said, is if these children are healthy enough to have their own children. If they are, they might be the key to the survival of the sawfish.