These new findings shed light on why parents might cannibalize their own young.
A wide range of animals gobbles their own kids � polar bears, burying beetles, hamsters, wolf spiders and a range of fish species. Such actions are puzzling, given all the time and energy that goes into producing offspring that are supposed to continue one’s genetic legacy.
To further understand why such cannibalism might happen, scientists focused on the sand goby (Pomatoschistus minutus), a fish in which the males alone take care of the eggs.
“Overall, dad does a pretty good job of taking care of the eggs, except for one thing � he tends to eat about a third of them,” said researcher Hope Klug, an evolutionary biologist at the University of Helsinki in Finland. “Based on previous work in this species, we know that the males aren’t just doing this because they’re hungry � even when they have excess food, they continue to eat a really large number of their own eggs.” …
The scientists found the males preferred to eat larger eggs � which take longer to hatch � from the second female they spawned with. They conjecture the fish do so to cut down on the amount of time spent caring for their young, thereby enabling the dads to reenter the mating game sooner.
Sand goby dads have to care for thousands of eggs “until they hatch � about one to two weeks � and during this time he isn’t able to attract any new females,” Klug explained. Eating his young might “allow him to increase the total number of offspring he produces over the breeding season.” …