Baby starfish may look innocent and adorable, but they are tiny cannibals and eat siblings for their own survival.
Young starfish eat their siblings for their own survival, according to new research. Two researchers accidentally discovered this behavior in the small starfish Asterias forbesi. Initially, they tried to understand how young starfish respond to ferocious crab predators in the laboratory.
“But all the starfish we tested started eating each other even before we released the crabs. We had to give up this experiment, ”explains John Allen, assistant professor of biology at William & Mary College. So Allen and his team set out to observe this previously unknown phenomenon among young starfish.
The starfish Asterias forbesi, which is commonly found on the east coast of the United States, grows to be 11.9 to 24 cm long as adults, according to National Geographic. Juveniles are mostly pinhead-sized copies of their parents, Allen says. In the process of growth, they undergo metamorphosis – they turn from an immature form into an adult, just as caterpillars turn into butterflies.
Although juveniles of Asterias forbesi are roughly the same size, the larger ones always end up eating the smaller ones, according to a new study.
Scientists have found that young starfish exhibit cannibalism as early as four days after metamorphosis.
Cannibalism between siblings can give individual stars an adaptive advantage, Allen said. Moreover, adult female sea stars lay from 5 to 10 million eggs per year.
The results are published in the journal Ecology.
Although this behavior was unknown to this species, cannibalism is not uncommon in the animal kingdom: more than 1,300 species (including humans) have been reported to exhibit it, according to the statement. The researchers believe cannibalism is likely to be even more prevalent in small animals, including young ones.