Fish

Two endangered female sharks found to be reproducing asexually in the absence of males in what appears to be a vital survival mechanism amid declining male populations.

Surprising new research has revealed why the world's longest-living vertebrate, the Greenland shark, has such a lengthy lifespan. The findings could have big implications for the species' future.

A decade after a huge mako shark dubbed "The Beast" was caught off the California coast, experts search for its enormous relatives.

Tasselled wobbegong sharks are so well camouflaged they can vanish on the seafloor, waiting for unsuspecting prey to pass before lunging forward to suck their victims into their giant mouths.

Sharks in the Gulf of Mexico are learning to associate boat engines with food, leading to more and more cases of depredation, experts say.

A new species of piranha-like fish called pacu was recently found hiding in plain sight among several near-identical species in the Amazon River. Researchers have named it after Sauron from "The Lord of the Rings."

A rare giant hoodwinker sunfish that washed ashore Gearhart beach in Oregon could be the largest of its species ever sampled.

People had linked recent shark attacks in the Florida panhandle to orca activity in the Gulf. But a combination of dry weather and heat was the real driving force.

Despite numerous tests, experts still can't figure out why smalltooth sawfish in Florida are dying in such a strange way — spinning, thrashing and beaching themselves.

A female Pacific footballfish was found dead on an Oregon beach — potentially for the first time ever. It is currently unclear what killed the alien-looking creature and how it was dragged up from the depths.