Feeding offspring with nutrient-rich milk is a typical trait of mammals. Researchers were accordingly surprised when they discovered an amphibian that produces nutrient milk. The egg-laying, worm-like species provides its young with a substance rich in fat, the team reports in the specialist journal Science. The mini amphibians therefore demand food several times a day, probably in a similar way to bird chicks, with sounds and touch.
Apart from mammals, in vertebrates the yolk of the embryo is usually the only source of nutrition that mothers give their offspring from their own production at the start of life. Certain spiders, cockroaches, fish, and birds are known to feed their offspring with a nutrient-rich substance that is functionally similar to mammalian milk.
The team led by Carlos Jared from the Instituto Butantan in São Paulo has now investigated the behavior of the ringworms (Siphonops annulatus) studied in South America, a subterranean species of creeping amphibian. 16 females, each with four to 13 young, were included. It was observed that the offspring ingest a highly viscous substance from the outlet at the mother’s rear end and then show signs of satiety such as reduced activity.
It was previously known that young animals eat the skin from their mothers’ bodies
The young are fed several times a day in the two months after hatching, apparently in response to certain touches and high-pitched sounds. The researchers explain that this type of communication between parents and offspring is not known in any other amphibian. The lipid- and carbohydrate-rich substance, which the researchers call milk, is produced in special glands in the mother’s fallopian tubes.
A ringworm protects its eggs.
(Photo: Carlos Jared)
The ringworms Siphonops annulatus is an exceptional amphibian anyway. The primitive, blind animals, which are up to 40 centimeters long, produce a poison with which they can apparently weaken prey or attackers. While other amphibians store such a secretion in their skin, the ringworm has a mouth with poisonous teeth, comparable to snakes. Recently, researchers also discovered that the animals secrete mucus at both ends of their bodies in order to be able to move more quickly and deter pursuers. And feeding the offspring has previously been considered idiosyncratic.
In the case of egg-laying species of sycophants, it has been documented that young animals eat their mother’s skin, which is enriched with fatty substances, from their bodies over a period of two months. During this time, the mothers do not leave their young once to eat something themselves, as Jared’s team explains. Also at Siphonops annulatus This skin feeding existed, and the mothers spent most of the time curled up in one place with the young animals on their backs, it was said. However, skin feeding was observed much less frequently than milk feeding.
According to Jared’s group, the good care has a clear impact: the young are growing quickly. Their body mass increases by around 130 percent in the first week after hatching alone.