Generalized reciprocity in vampire bats?

"Direct reciprocity" occurs when individuals are more likely to help individuals that helped them previously, while "generalized reciprocity" (also called "upstream reciprocity") occurs when individuals are more likely to help after they have been helped by any individual. So direct reciprocity is like "I'll scratch your back if you scratch mine" and generalized reciprocity is … Continue reading Generalized reciprocity in vampire bats?

Vampire bats will feed trapped individuals through a cage wall

Cooperative behaviors, such as food sharing, can be studied under a spectrum of conditions from completely natural to very artificial. For example, a careful observer in the field can measure the extent to which male chimpanzees will share meat in the wild after a hunt, or an experimenter in the lab can test the extent … Continue reading Vampire bats will feed trapped individuals through a cage wall

Food sharing in vampire bats: reciprocal help predicts donations more than relatedness or harassment

New paper available here Key points We re-examined the well-known but controversial case of reciprocal food sharing in vampire bats. What factors predict the decisions of vampire bats to donate food to hungry roost-mates? In collaboration with the Organization for Bat Conservation, we collected a larger sample of food sharing data than ever before under … Continue reading Food sharing in vampire bats: reciprocal help predicts donations more than relatedness or harassment

Poster with recent findings

The poster below was the winner for the University of Maryland Bioscience Day 2012 Poster Competition for the category Biodiversity, Conservation, Ecology & Evolution, and Environmental Science. More importantly, it summarizes the findings in a recent manuscript we submitted. Click to see full size

Do you think juvenile vampire bats would regurgitate food to their hungry parents?

The benefits of helping: direct and indirect Biologists divide the evolutionary benefits of helping others into two categories. Direct fitness benefits means helpers tend to have more offspring, all else being equal. Indirect fitness benefits (or kin selection) mean that helpers pass on more of their own genes because their relatives have more offspring. Kin … Continue reading Do you think juvenile vampire bats would regurgitate food to their hungry parents?

Cooperative male alliances in bats

A paper just published on gelada baboons entitled "Concessions of an alpha male? Cooperative defence and shared reproduction in multi-male primate groups" claims to be among the first demonstrations of cooperative male defense of a female group in a mammal. But the authors seemed to have forgotten that bats are also mammals. A little background: most mammals live in … Continue reading Cooperative male alliances in bats

Clarifications about inclusive fitness and multi-level selection from David Queller

Misunderstandings about the "group selection controversy" continue to rumble on for some reason (especially in the study of humans), even though inclusive fitness (kin selection) and multi-level selection (group selection) are simply two alternative equivalent ways of modeling and talking about the same evolutionary reality. Here's a link to a discussion of the group selection controversy … Continue reading Clarifications about inclusive fitness and multi-level selection from David Queller

“Do vampire bats have friends?”

I came across this TV clip from 15 years ago with Jerry Wilkinson talking about his study on vampire bat food sharing...

Why vampire bats are a good experimental model of cooperation: natural, cognitive, and controllable

Sociability is as much a law of nature as mutual struggle. -Kropotkin (1902) Mutual Aid: A Factor in Evolution Ever since Darwin realized that his concept natural selection was the key driver of evolution, he and other biologists pondered one of the most puzzling and interesting questions in biology: why would individuals that help others … Continue reading Why vampire bats are a good experimental model of cooperation: natural, cognitive, and controllable

Why are we so nice? Tales of human generosity, a “moral molecule”, and cooperation in rats

Everyone seems interested in human cooperation, even though humans are not as cute as other animals, like bats. But I figured I would write a blog post mainly about cooperation in humans (...but also other animals too). Imagine you and I are playing a trust game, an anonymous game played over a computer. We both … Continue reading Why are we so nice? Tales of human generosity, a “moral molecule”, and cooperation in rats