Some look like cartoon sheep and others like Pokemon characters. Some are cannibals and some are poisonous — and some just like to look extra fancy so that eating them seems like a risky proposition. Some have evolved to look and move like fish, though they're definitely not! They are nudibranch, small creatures found from tide pools to deep sea valleys throughout the world's oceans.
As we've noted previously when we explored the sheer variety of species, "There are more than 3,000 species of nudibranch worldwide and more species are being discovered all the time. Nudibranch species vary wildly in coloration and size. Some species live only a month, while other species live for a year. Some species grow to only about one-quarter inch long, while other species can grow to as long as 12 inches."
Some of our favorite facts about these creatures include:
1. Nudibranchs have tentacles, called rhinophores, on top of their heads to help them smell food, competitors and potential mates. To protect them from potential nibbles from hungry fish, many species of nudibranch can pull the tentacles into a pocket of skin and hide them until danger passes.
2. Like slugs found on land, nudibranchs leave a slimy trail behind them as they move across an underwater surface.
3. Some nudibranchs can make sounds. In 1884, Philip Henry Gosse reported observations by "Professor Grant" who noted that two species made sounds similar to that of steel wire tapping on a glass jar. The observed sounds could be heard at a distance of 12 feet in a small apartment!
We could go on and on about nudibranchs, or we could just let you watch this fantastic 45-second video jam-packed with facts about these weirdly wonderful underwater creatures: