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 311 RELATED ARTICLESMORE FROM AUTHOR Animals World’s Fastest Animal 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 Tell us what you think!