Cannibalism of offspring may be adaptive reproductive strategy and could occur by two mechanisms. Complete cannibalism of small broods may allow parental resources of time and energy to be reallocated to larger broods yielding a higher net return on parental investment. Complete brood cannibalism has been induced experimentally. Alternatively partial cannibalism by a male parent of some of its offspring may provide energy for continued care of young. Though widely quoted this strategy may not yield the cannibal a net gain in fitness and has no empirical support.