Kingdom = Animalia
Phylum = Chordata
Class = Mammalia
Order = Chiroptera
Family = Phyllostomidae
Subfamily = Desmodontinae
Species = Diphylla ecaudata
An average sized bat (about 85 mm), greyish-brown or reddish-brown, with no tail and hairy webbing between its legs. It has short, rounded ears, and a pug nose. And it drinks blood! Mostly just birds' blood. But still, it's pretty cool. (If you think Hairy-Legged is a silly name, it could just as easily have been the Chicken Vampire Bat. "Go lock up the hen house Ma, the bats are comin'!" Heh heh. So that's where Vampire Chicken comes from. Okay, back to the writeup).
They live about 9 years, and become sexually mature at nine months. They reproduce year-round, yet despite this are the rarest of the vampire bats. They live in tropical and subtropical forest lands, ranging from the southern US southward through eastern Mexico and most of Central America, and into South America at least as far as Peru and southern Brazil. They live primarily in caves, but have also been found in mine tunnels and hollow trees.
The hairy-legged vampire has 26 teeth, more than the other vampire bats. They draw blood with their large middle-upper incisors (not their canines). They have heat-sensors in their noses, enabling them to find where the victim's blood runs closest to the surface of the skin. The bats usually go for the legs and cloacal region. They then lick the bite area to soften the skin and clear the area of feathers of fur. Finally they bite a small, V-shaped cut and suck up the blood. An anticoagulant in their saliva keeps the blood flowing smoothly for about an half-hours worth of feeding (about 5 teaspoons -- equal to about half their body weight). The whole process is usually carried out without the victim noticing. Afterwards, the bat urinates continuously until it is light enough to fly.
A hairy-legged vampire can go for two nights without food before starving. Although the bats are usually solitary, they can and do share food among friends (it involves regurgitation, I believe. On an unrelated note, the bats aren't entirely solitary. They will form groups of up to 12 individuals). Because they are feeding on blood, they can transmit various diseases between animals (and, in theory, humans), although there isn't any evidence that this is a large problem. They are a possible transmitter of bovine paralytic rabies.
A note on the aforementioned anticoagulant; hairy-legged anticoagulant is about 20 times more powerful than any other known anticoagulant. Their saliva has been used as a blood-thinning drug to treat heart attacks and strokes in humans.
My biggest and best sources of information for this WU were:
http://animaldiversity.ummz.umich.edu/site/accounts/information/Diphylla_ecaudata.html
and
http://www.nsrl.ttu.edu/tmot1/diphecau.htm