![]() ![]() ![]() The other two sanguivorous bats, the hairy-legged vampire and the white-winged vampire, prey on sleeping birds perched in trees. It creeps along the ground at night, and then springs up to three feet high onto its quarry. The common vampire bat (which, as its name suggests, is the most widespread) feeds on the blood of cattle and other livestock. These animals can starve to death in 48 hours." "Not only do they have to get it every night, but they have to get enough of it not to starve. "They have to feed on blood constantly," says Schutt. They slip their slim, sharp incisors and canines into the flesh of mammals or birds, and then lick up the blood seeping from the wound (it keeps flowing because of anti-coagulants in their saliva), swallowing up to five teaspoons' worth-about half their body weight-in a feeding. These flying mammals, native to South America, Central America, and two Caribbean islands, are about the size of a mouse. Of the world's more than 1,000 bat species, only three drink blood. Since the 1930s they've been competing with an invasive species, the sea lamprey, which Great Lakes officials have spent decades trying to combat and prevent from spreading further. Two parasitic lampreys, silver and chestnut, are native to the Great Lakes. While such attacks might kill smaller fish, victims that escape carry a visual reminder of the encounter: a circle-shaped scar. They strike their quarry with their circular mouth, holding on with their hook-like teeth for hours or even days as they eat. ![]() These incredibly successful hunters attach themselves to other fish species and even marine mammals. As adults, however, certain species are parasitic. Sometimes called eels because they have long eel-like bodies, they spend the first several years of their lives as harmless larvae. Lampreys are jawless fish that live mostly in coastal and fresh waters. "I guess this behavior evolved because if they swarmed the booby, it would get upset and move away." The booby doesn't appear to suffer any long-term damage from serving as a donor. "It's pretty comical to see three or four birds just waiting for the next bird to move away," says Schutt. Only one bird will drink from the booby at a time, but others line up behind. The vampire finch, the only bird known to consume blood, acquires the liquid-iron supplement by pecking the wing and tail of the blue-footed booby until it bleeds. The vampire finch of the Galapagos Islands is not, as Schutt says, a "card-carrying vampire." It sups on the red stuff in addition to its regular diet of seeds, nectar, and eggs. Hirudin, for example, an anti-coagulant found in leech saliva, is used to prevent blood clots after surgery. While sanguivores can be deadly-not because they drain you dry but because they carry diseases-many are merely nuisances to humans. Finally, bloodsuckers have developed anti-coagulants that keep the red liquid flowing while they feed. Incredibly sharp teeth, or comparable tools, slice into flesh easily, decreasing the pain inflicted on the host. They have finely tuned sensory systems that home in on their next meal. Most vampires are small, which helps them to evade detection. While so-called sanguivores are a diverse group, they face similar challenges in finding and feeding on blood, and have evolved a variety of adaptations to suit this specialized diet. "I'm surprised there aren't more animals that evolved to have it as part of their diet." (Scroll down for a list of 10 real-life vampires.) "There's blood everywhere," points out Bill Schutt, vampire bat researcher and author of Dark Banquet: Blood and the Curious Lives of Blood-Feeding Creatures. While they might sound like characters in an Anne Rice vampire novel, animals ranging from leeches to bats and even birds consume blood. All, however, are after the same prize: warm, oozing blood. Many of them have razor-sharp teeth, and some can jump up to 150 times their own height or defy assassination attempts. Others are so stealthy or well camouflaged that their victims never see them coming. Some emerge at night, creeping up on their unsuspecting prey under cover of darkness.
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