Okay, so who drinks blood? Let's name some animals: mosquitoes, bats, leeches, ticks, probably some other kinds of bugs. Vampires...

When I started this script that's all that I could come up with off the top of my head, but then I did a bit of research, and there are a number of bloodsuckers that you might want to keep your eye out for that you've probably never even heard of. So let's fix that. Because SciShow.

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So this is science - let's not call it vampirism, rather we're gonna call it 'hematophagy': just, consuming blood. And there's plenty of nutrition and moisture in blood, and if you're careful about it you can keep the host alive and have a nice long-term parasitic relationship going on. It's a good strategy, and one that's been adopted quite a bit. So let us discuss our six surprising bloodsuckers, starting off with the candiru.

You may have heard that if you're peeing in the Amazon a fish might swim up your urethra and start sucking blood from the inside of your body. The fish in this situation is the candiru, a small parasitic catfish, and it's not the only kind of parasitic catfish. It latches on to victims like a leech, sucking a nice blood meal and then swimming off. And yes, they will happily take a meal from a human. The 1997 case of a candiru being removed from the inside of a human urethra is... a controversy. It appears to have been a straight-up hoax but there's still discussion going on about it. But probably not. Let's just say probably not. Thankfully.

Now on to some more familiar but still surprising territory. Of the more than one thousand species of bats on Earth, three drink blood. The most common of them, the aptly named common vampire bat, has super sharp incisors. It sneaks up on animals in the dark, literally crawling toward them, makes a tiny little incision and then laps up the blood. Maybe not cute, but certainly not what the movies might have you imagining.

Number three! Back to the blood-sucking fishes. The lamprey is one of the coolest and most ancient fish in the sea, and some species have a terrifying spines suction cup that they use to clamp onto a fish, spine them, and then suck 'em dry. Trouble with being a fish: you've got no hands to just yank the thing off.

Worse than their parasitic habits: lampreys have become an insidious invasive species in America and were a major cause of the collapse of the Great Lakes fishing industry in the forties and fifties.

Number four you're probably not expecting: the hood mockingbird. A cute little bird from the Galapagos Islands that feeds opportunistically, no big deal, except that one of its favorite sources of food appears to be open wounds. The mockingbird will flit around the sea lions, drinking up blood from their open wounds. It's even been known to drink the blood right off of the legs of injured researchers. As this behavior increases during the dry season, it may be that the bird is more interested in the moisture than the nourishment of the blood. This technique isn't unique to the hood either. The vampire finch, also endemic to the Galapagos, is not so opportunistic, actually pecking blue-footed boobies until they bleed and drinking up the result.

Number five! Butterflies. Yup. But let's be clear: lots of animals drink blood when they have an opportunity, just not exclusively. Interestingly this includes some mosquitoes, which will suck the juice from fruits and animals equally. And yes, many butterflies enjoy the nutrients and minerals made available by a nice pool of blood if one happens to be nearby. The good news is: there are no butterflies actually capable of inflicting bloody wounds.

And finally number six. Humans. Black pudding, blood sausage, ... yes, stuff that people still regularly eat all over the world. In Finland pig blood is mixed with milk, flour, and molasses to make blood pancakes. Nomadic cultures often nurse themselves in the blood and milk of their livestock, keeping the animals alive while allowing their human parasites to thrive alongside them. Yep, vampires. You see one in the mirror every morning.

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