Vampire Bats
Vampire bats, which primarily feed on livestock or other vertebrates, must obtain a meal every 48–72 hours or face starvation. On a given night, there are individuals that do not successfully feed. Fortunately for them, a successful individual may regurgitate their meal for the unsuccessful individual. In order for this trait to have persisted through evolutionary time, a level of recognition is necessary among individuals. An altruistic bat may refuse to regurgitate blood for another bat that has not given blood to others in the past. The mechanism for this reaction is not known.
Read more about this topic: Reciprocal Food Sharing
Famous quotes containing the words vampire and/or bats:
“If I’ve killed one man, I’ve killed two—
The vampire who said he was you
And drank my blood for a year,
Seven years, if you want to know.”
—Sylvia Plath (1932–1963)
“Bats have no bankers and they do not drink
and cannot be arrested and pay no tax
and, in general, bats have it made.”
—John Berryman (1914–1972)