Did you know that Tasmanian hens have two husbands? That cellular slime molds commit suicide? That vampire bats will share food with hungry fellow bats and that hanuman langurs commit infanticide? Why creatures great and small behave in such fascinating and seemingly perplexing ways is explained in this delightful account of the evolutionary foundations of animal social behavior.

Only in recent years have biologists and ethologists begun to apply careful evolutionary thinking to the study of animal societies--and with spectacular results. This book presents the choicest of these...