In studying the hundreds of offspring produced, which some on the internet have named sturddlefish, the researchers found that they fell into one of three main categories: those that looked mostly like their mothers, those that looked mostly like their fathers and those that inherited features of both parents. Both of the parent fish are endangered, and they would not have had any chance of reproducing in the wild—as their names suggest, the paddlefish live in the U.S. and the sturgeon live in Russia. They are both considered to be "living fossils" by scientists because they have not changed very...