Home Science Biology Altruism ScienceAnimalsBiology Altruism Hank explains the evolutionary basis for altruistic behavior in animals, including vampire bats! By Watch and Study - Mar 24, 2016 240 RELATED ARTICLESMORE FROM AUTHOR Animals How do schools of fish swim in harmony? Biology Why Aren’t There Giant Insects? Biology Bird or Dinosaur? Biology Human sperm vs. the sperm whale Biology The brilliance of bioluminescence Tell us what you think!