Vampire Bats
U.S. National Science Foundation
https://www.nsf.gov/news/mmg/mmg_disp.jsp?med_id=73293&from=
There are over 900 species of bats in the world (Smithsonian), and of those, only three species drink blood: the common vampire bat (Desmodus rotundus), the hairy-legged vampire bat (Diphylla ecaudata), and the white-winged vampire bat (Diaemus youngi). Vampire bats expend significant energy flying out at night to obtain blood meals, and because blood is not a high-calorie food, they face the risk of starvation if they don’t feed nightly. However, finding a successful blood meal can be hit or miss. To address this challenge, well-fed vampire bats share their meals by regurgitating blood to feed individuals that haven’t successfully fed. This sharing behavior helps them form strong social bonds, as they remember past favors and reciprocate in the future (Greenfieldboyce, 2019).
Vampire bats can carry rabies and transmit it to humans, although such cases are rare. Rabies transmission is a more significant issue for cattle, as vampire bats prefer cattle over humans as prey. Vampire bats are known to carry paralytic rabies (Sota), a form of rabies that causes paralysis and lethargy rather than aggression. This contrasts with the furious form of rabies, which causes aggression and hyperactivity (Chopra et al., 1980). The lack of aggression associated with the paralytic strain suggests that it is heavily dependent on vampire bats, indicating a coevolutionary relationship between the virus and its host. This relationship underscores the virus’s reliance on the bats survival and social behaviors to persist within ecosystems.
Human activities significantly affect vampire bats, but the nature of the impact depends on how habitats are altered. For example, hydroelectric dams create uninhabitable environments for bats by flooding or destroying roosting sites. Cattle ranches destroy rainforests but provide an abundant food source for vampire bats in the form of cattle, which they prefer over their traditional prey, such as tapirs and peccaries. Cities can have mixed effects; they may reduce food sources but also provide new roosting opportunities, such as under overpasses or in abandoned buildings (Johnson et al., 2014). These are just a few examples of the myriad of ways in which human alterations to the landscape can influence vampire bats and their interactions with the environment.
Human activity also influences rabies transmission. Cattle ranches increase the risk of rabies spreading among livestock, while urban environments can lead to a rise in human cases, although feeding on humans remains rare (Johnson et al., 2014).
It is essential not only to recognize the ways human activity affects rabies transmission but also to consider vampire bats as complex, social creatures in their own right. They form tight social bonds, care for one another, and are simply trying to survive in an ever-changing world.
References:
Bat Facts Smithsonian
https://www.si.edu/spotlight/bats/batfacts
Greenfieldboyce, Nell (October 31, 2019) For These Vampires, A Shared Blood Meal Lets 'Friendship' Take Flight NPR
Sota, Arrellano. Control of bovine paralytic rabies in Latin America and the Caribbean Food and Agriculture Organization
https://www.fao.org/4/v0600t/v0600T0a.htm
Chopra, J. S. Banerjee A. K. Murthy J. M. Pal S. R. (December 1980) Paralytic rabies: a clinico-pathological study PubMed
https://pubmed.ncbi.nlm.nih.gov/7437890/
Johnson, Nicholas. Arechiga-Ceballos, Nidia. Aguilar-Setien, Alvaro. (April 29, 2014) Vampire Bat Rabies: Ecology, Epidemiology and Control PubMed