<P> Vampire bats use infrared radiation to locate blood hotspots on their prey . A recent study has shown that common vampire bats tune a TRP - channel that is already heat - sensitive, TRPV1, by lowering its thermal activation threshold to about 30 ° C . This is achieved through alternative splicing of TRPV1 transcripts to produce a channel with a truncated carboxy - terminal cytoplasmic domain . These splicing events occur exclusively in trigeminal ganglia, and not in dorsal root ganglia, thereby maintaining a role for TRPV1 as a detector of noxious heat in somatic afferents . The only other vertebrates capable of detecting infrared radiation are boas, pythons and pit vipers, all of which have pit organs . </P> <P> Vampire bats tend to live in colonies in almost completely dark places, such as caves, old wells, hollow trees, and buildings . They range in Central to South America and live in arid to humid, tropical and subtropical areas . Vampire bat colony numbers can range from single digits to hundreds in roosting sites . The basic social structure of roosting bats is made of female groups and their offspring, a few adult males, known as "resident males", and a separate group of males, known as "nonresident males". In hairy - legged vampire bats, the hierarchical segregation of nonresident males appears less strict than in common vampire bats . Nonresident males are accepted into the harems when the ambient temperature lowers . This behavior suggests social thermoregulation . </P> <P> Resident males mate with the females in their harems, and it is less common for outside males to copulate with the females . Female offspring often remain in their natal groups . Several matrilines can be found in a group, as unrelated females regularly join groups . Male offspring tend to live in their natal groups until they are about two years old, sometimes being forcefully expelled by the resident adult males . </P> <P> Vampire bats form strong bonds with other members of the colony . A related unique adaptation of vampire bats is the sharing of food . A vampire bat can only survive about two days without a meal of blood, yet they cannot be guaranteed of finding food every night . This poses a problem, so when a bat fails to find food, it will often "beg" another bat for food . A "donor" bat may regurgitate a small amount of blood to sustain the other member of the colony . For equally familiar bats, the predictive capacity of reciprocity surpasses that of relatedness . This finding suggests that vampire bats are capable of preferentially aiding their relatives, but that they may benefit more from forming reciprocal, cooperative relationships with relatives and non-relatives alike . Furthermore, donor bats were more likely to approach starving bats and initiate the food sharing . These findings contradict the harassment hypothesis--which claims that individuals share food in order to limit harassment by begging individuals . All considered, vampire bat research should be interpreted cautiously as much of the evidence is correlational and still requires further testing . </P>

How did the vampire bat get its name