4. Zombie Worms
Siboglinid osedax. Its not just sharks and crabs and glowing fish at the bottom of the sea. There are also the much smaller creatures which everyone else feeds on. But what do the little guys feed on? Easy. Whales. Osedax is Latin for bone eating, which gives these worms their other common name, and they have been mostly found on the bones of whales. Whale falls is the term used to describe the ecosystem that develops when a whale carcass falls to the sea floor. Given the size of most whale species, there is enough nutrition in a single carcass to sustain an ecosystem for over 10 years. Over the long decay of the whales body, numerous species feed from it, including sleeper sharks. When its mostly just bones, thats when the zombies take over. This is rather impressive when you consider that Zombie worms are so named because they have no eyes or even mouths. Rather than eat the bones, they use a secreted acid to bore into the bones and a symbiotic bacterial species to consume the nutrients locked in the bone. The bacteria are essential in aiding the worms digestion as they also lack a stomach. This might sound like they're ill equipped for life in general but they are actually one of the most diverse creatures of the deep sea. There is some controversy about how this might be as it isn't known how picky they are about the type of bones they feast on. Some scientists argue that they exist solely on whales, while others point out that given the tremendous gaps in both time and space between whales falling, the worms would have to be able to eat other bones. There is evidence to suggest however that theyve been at it a very long time. Similar burrow marks to those on whale falls today have been found on the fossilised remains of ancient sea birds and even plesiosaurs.