Blood Sucking Vampire Bats Sing Duets
This article is pretty cool, especially because it's Halloween. When you think of friendly, family oriented animals, vampire bats probably do not spring immediately to mind. However, new research shows that vampire bats may sing coordinated duets with each other. In this article, researchers explain how singing has been recorded in other species, and between mother-pup pairs in other bat species, but never before between adult bats. New research shows that adult White-winged vampire bats may exhibit this behavior. 18 white-winged bats were tested in the experiment. It was found that when chickens, a popular source of blood for the bats, were brought near them, the bats became very vocal. It was also found that when the lights were turned off, the bats started calling out. Surrounding bats responded to the initial caller within 1/4 of a second after the first call. Each bat was also found to have it's own unique call that other bats could identify it by. The scientists conducting the test believes the calls could be a mechanism for bats to find one another when seperated, as well as being a way for a bat to convey how it is feeling. While this group oriented behavior may seem strange in an animal that has so many negative stereotypes, it's interesting to note that vampire bats are one of the few species known to exhibit reciprocal alturism, meaning they are known to share food with more unsuccessful members of its group.

Edit 11/4
According to encyclopedia.com, reciprocal altruism occurs when "when the actor acts altruistically in expectation of having the same done in return at a later time. " So, the bat will help out less successful group members, knowing that this increases his chances of being helped in the future. Not many other animals besides humans are known to display alturism. One form of alturism, kin selection, where an animal will help its close relatives survive at a cost to itself, is shown in the Kenyan Bee-Eating bird. This bird will wait until it is older to produce its own young, instead helping its older family members raise their chicks. (This information can be found here.)
In regard to the song the bats produce, they are NOT on the same frequency as echolocation, since they are at least partially audible by humans. As to what they are singing about, or why they are doing it, that hasn't been determined yet. One theory is that it helps identify who belongs in the same group. This goes back to the reciprocal alturism. Each bat's individual song may identify it to others, so a bat will know if it's his group mate who's asking for a snack, or just some random individual that he should ignore.
Just as a side note, does everyone know that vampire bats don't actually drink enough blood to harm most large mammals? It's more like a bad mosquito bite. The real danger lies in the diseases they can pass on, such as rabies.

-Corinne Delisle (7)