Fishy Paternity Defense: Bluegill dads: Not mine? Why bother?

Bluegill sunfish have provided an unusually tidy test of the much-discussed prediction that animal dads’ diligence in child care depends on how certain they are that the offspring really are their own.

DAD’S NEST. Among a crowd of protective fathers, the big bluegill male in the foreground hovers over his egg-filled depression.