SCIENCE LAB SCHEME : SLIMY RULE BREAKERS

Slimy Rule Breakers : ' Wormlike and oozing milk for their amphibious babies :

Most vertebrates, like birds, reptiles, amphibians and fish, reproduce by laying eggs filled with nourishing yolk that their offspring use as an initial source of nutrition before hatching.

Mammals change the game by giving birth to live young and feeding them fatty, sugary milk as they get on their feet.

But Nature breaks rules at the time, and the latest animals to confound the yolk versus milk binary are caecilians, the egg-laying, legless amphibians that look like worms.

Research published in the journal Science suggests they feed their hatchlings a milk-like substance, too, but from their behinds. It adds to the curiousness of caecilians, which were already known for feeding hatchlings skin ripped off their mother's back as a postnatal nutritious snack.

Since 1987, a team headed by Carlos Jared, the Butantan Institute in São Paulo, Brazil, has collected 16 mothers of the Siphonops annulatus species of caecilians species, and their hatchlings. Each mother has four to 13 babies.

They filmed each family during the two months from hatchings until the amphibians became independent. Each mother never left her litter, not even to feed, and hatchlings wriggled around on her back and nuzzled up to the end of her body.

This is where the offspring competed to nibble a white liquid from her mother's cloaca, placing their heads almost inside it. [ Sofia Quaglia ]