When it comes to making sacrifices for their children, some moms put other parents to shame. That's especially true of wormlike amphibians called Boulengerula taitanus, whose eggs hatch in small underground burrows. Because food is scarce there, mom turns her skin into a nourishing meal, which her young peel and eat until they are big enough to leave the nest.
Zoologist Ronald Nussbaum of the University of Michigan in Ann Arbor and his colleagues made the distasteful discovery while studying B. taitanus nests in captivity (the worms are native to southeastern Kenya).
Observations of 21 females and 66 youngsters revealed that—after feeding on their mom's skin for 1 week—youngsters increased their length on average 11%, or 1 mm per day. Maternal weight loss over the same period was consistent (14%) with offspring growth. The stomach of the young contained only skin, the team reports 13 April in Nature, indicating this was their sole source of food.
Fortunately, mom survives the frenzy. Nussbaum speculates that B. taitanus mothers avoid being eaten alive by coordinating their cycles of skin shedding with the periodic bouts of offspring feeding. Having thick skin also helps: Detailed analysis of the skin of brooding females shows that it is up to twice as thick as that of nonbrooding females. In addition, says Nussbaum, B. taitanus larval "teeth are specialized for stripping only the outer layer of skin and can not penetrate very deep down."
Cannibalism has been noted in some species, but this is the first example of amphibian mothers providing for their children in this way, notes evolutionary biologist Gerald Borgia of the University of Maryland, College Park. "Discovering a whole new way of parents taking care of their babies is a pretty significant event in evolutionary biology," he says.
By Al Staropoli | ScienceNOW Daily News