Grebe: Eats Feathers
Here's another fact about grebes that I didn't mention last week; grebes eat their own feathers. The adults even feed their own feathers to their young, starting at just a few days old. Why would
they do such a thing? Feathers have no nutritional value and they cannot be easy to swallow. The reason is because of the fish they eat which make up the main part of their diet. A grebe's gizzard and stomach are not very well adapted to crush and digest fish bones. It is thought that by swallowing large amounts of feathers, the feathers not only pad the stomach from the pointy fish bones, but may also slow digestion, giving the stomach more time to digest the bones before they pass into the intestines.
Vampire Squid: Eats Dead Stuff, Plankton, and Poop
Let me answer your first question. The vampire squid was not named for its dining habits, but rather for its resemblance to Dracula: it has skin that can appear black, eyes that can appear red, and a "cape" of skin between its arms. And what is unusual about this squid's diet is that it is the only cephalopod (the group that includes squid, octopuses, cuddlefish, and nautiloids) that is not a predator. The vampire squid lives in waters too deprived of oxygen for its predator relatives and has adapted to the harsh conditions by taking the easy road for finding food. It uses two filaments, up to 40" long and equipped with sensory cells and stiff hairs, to catch what is known as "marine snow" as it floats through the water. Marine snow is essentially the garbage of the animals that live in shallower water, containing dead animal parts and excrement, with some plankton thrown in for good measure. When oxygen is at a premium, you need to conserve as much energy as possible, and the vampire squid has found a way to do just that. Why waste all that energy hunting food as a predator when you can wait with open arms (err, filaments) for food to come to you?
Vampire Moth: Eats Blood
Now here is an animal that lives up to its name. In 2008, scientists discovered a new species of moth in Siberia that feeds on blood. It appears to be a close relative of moths that feed on fruit, and so scientists are now trying to discover why the divergence to a new food source. At the time of its discovery, only males of this moth have been found to feed on blood, so it is suspected that the blood is used as a gift to females to win over mates. If you want to see some truly cringe-worthy footage of vampire moths drilling their proboscises into willing victims, then click the video below.
I think I need to go watch some cat videos now to get that image out of my head.
Cave Cricket: Eats its Own Legs
Like the vampire squid, the cave cricket lives in a harsh environment. Living your whole life in a deep, dark hole, one doesn't come across a food source on a regular basis. To avoid starvation, cave crickets will chew off their own large hind legs as a kind of cannibalistic renaissance fair drumstick. It's a sacrifice that can only be made twice, as the consumed leg does not grow back. Some cave crickets and their relatives, camel crickets, can be found in basements, including my own. Here too, food may not come that easily (unless they want to eat lint, 'cause that's about all I have to offer down there) so even urban crickets may resort to eating their own limbs.
Looks like this guy got hungry.
We may think the diets of grebes, vampire squid, vampire moths, and cave crickets are unusual and a bit unsavory, but then again they may wonder why we eat bull testicles. I think I'll stick with my nachos, pizza, and popcorn, thank you very much.