An unusual type of fish has the ability to produce entirely new species when it mates.
Blue whales, which are the largest animals known to have ever existed, see their hearts skip a beat when they grab a snack.
A fish in the Amazon River basin has developed a "bulletproof vest" to protect itself from piranhas' nasty bite.
Many living things twitch or make noises while they sleep, but octopuses actually flicker while they are resting.
Lurking in the waters of the Amazon basin is a new species of electric eel that scientists say can generate a greater electrical discharge than any other known animal.
Federal scientists said Thursday that they will be monitoring a new ocean heat wave off the West Coast, which could badly disrupt marine life.