A species of amphibian is the first observed to nourish its young with a milk-like product, which it squirts from the cloaca, a combined rear opening for its reproductive and digestive systems.
Siphonops annulatus is a blind, worm-like caecilian that lives underground. Lactation is considered a key characteristic of mammals, but a handful of other animals — including some birds, fish, insects and even spiders — produce nutrient-rich liquid for their offspring.
The finding that S. annulatus is “both a skin feeder and now a milk producer is pretty amazing”, says Marvalee Wake, an evolutionary biologist at the University of California, Berkeley. It is probably just one of the caecilians’ many biological quirks. “Most species have not been studied at this level of detail,” says Wake. “So, who knows what else they’re doing.”
