Alternatives to cow’s milk keep popping up. There’s oat milk, there’s goat’s milk, and now there’s amphibian milk (though you won’t find it on grocery store shelves). A team of Brazilian biologists have documented legless, subterranean amphibian mothers producing a milk-like liquid– packed with fats and carbohydrates–for their offspring. The research published March 7 in the journal Science is the first known instance of an egg-laying amphibian provisioning its babies with “milk.” The findings unveil new bodily functions and possible complex communication in an understudied animal weirdo.
Non-dairy discovery
Generally, milk is associated with mammals. After all, the word ‘mammal’ comes from the Latin mamma for “breast,” a reference to our taxonomic classes’ milk-producing mammary glands. But mammals are not the only group of animals to feed their babies with specialized secretions. Pigeons, penguins, and flamingos have “crop milk”–a goopy substance made by bird parents of both sexes within the lining of their digestive tracts. Some spiders and cockroaches, too, produce milk for their many-legged young. Enter caecilians, wormlike relatives of frogs, toads, and salamanders that live primarily in tropical areas.
Ringed caecilians (Siphonops annulatus) are one of about 220 known caecilian species worldwide, and are the newest addition to the list of milk-able animals. The odd, nearly-blind organisms live secretive lives under the soil and leaf litter of South American forests and grasslands. “They are one of the least-well understood vertebrates, because access to these animals is very difficult,” says Carlos Jared, senior study author and an integrative biologist at the Butantan Institute in São Paulo, Brazil. But the effort is worth it, he adds because caecilians are a “surprise box,” constantly offering up unexpected biological…
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