"We observed eight episodes of skin feeding by different young from five different broods," Nussbaum said. "In each episode, the young moved over and around their mothers' bodies, vigorously pressing their heads against their mothers while repeatedly opening and closing their mouths. They used their lower jaws to lift and peel the outer layer of the mother's skin."
Studies of the females' skin revealed that the outer layer is up to twice as thick in brooding females as in non-brooding females and is full of nutritious fat.
Amphibians are a diverse lot when it comes to parental care, which may include hiding, guarding, carrying and feeding offspring. Among caecilians---the order of amphibians to which B. taitanus and S. annulatus belong---some lay yolky eggs and tend them until they hatch but invest no energy in feeding the young after hatching; others bear live young that fend for themselves after birth.
In those that bear live young, fetuses are equipped with specialized teeth---something like those of B. taitanus and S. annulatus---that are thought to be used for scraping secretions and cellular material from the lining of the mother's oviduct. The skin-feeding behavior seen in B. taitanus may represent an evolutionary intermediate between these two reproductive modes, Nussbaum said.
The discovery of this never-before-seen behavior also highlights the importance of conservation efforts, Nussbaum said. "Concerns have been growing about amphibian populations that appear to be declining worldwide. Our discovery underscores the need for further studies to better document the amazing diversity of amphibian life history strategies and greater efforts to conserve it."
Nussbaum collaborated on the research with Alexander Kupfer and Mark Wilkinson of the Natural History Museum in London, UK; Hendrik Muller of Leiden University in the Netherlands; Marta Antoniazzi and Carlos Jared of Laboratorio de Biologia Celu
Source:University of Michigan