It may be an act of care, not sacrifice, when a male dyeing poison frog (Dendrobates tinctorius) leaves his newborn in water inhabited by larger, cannibalistic tadpoles. That’s the conclusion of a new study in which researchers observed the behavior of the 2-inch-long dyeing poison frogs around pools of water in French Guiana. When tadpoles hatch out of eggs, fathers carry their new offspring—one or two at a time stuck on their back—to small pools of water that have collected in plants or tree trunks, where the tadpoles are left alone to mature. Researchers found that while pool size and depth had little bearing on whether tadpoles were dropped off, the fathers were most likely to leave their newborns in pools that already housed larger, more mature tadpoles known to cannibalize smaller tadpoles. It may be dangerous for the newcomers, but it also indicates that the pool has the proper conditions for a frog to grow, the researchers hypothesize in the journal Behavioral Ecology and Sociobiology. In the natural pools observed, holding about 50 tadpoles at any given time, only 12 acts of cannibalism were observed during the study period, suggesting that many tadpoles make it to maturity without being eaten. More work will help researchers understand how the counterintuitive behavior has evolved and how pressure on habitats may have played a role.
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