Discoveries

April 02, 2024

Got Milk?

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Many mammals feed their young with milk – amphibians and other creatures, not so much.

Now, Brazilian biologists have discovered a species of amphibian feeding its offspring a milk-like secretion rich in nutrients, NPR reported.

In their study, they explained that the worm-like amphibian is a caecilian, an underground-dwelling creature descended from the same lineage as frogs and salamanders.

But unlike its relatives, it has a long segmented body without legs and functioning eyes – which makes them look a bit like earthworms with a head.

The research team was observing a particular species, Siphonops annulatus, when they came across their findings.

Mothers of this species give birth to wriggly babies, which later feed off the mother’s skin for nutrition. This process doesn’t bother the mother, but the team saw that at one point the entire brood would move to their parent’s tail.

That’s when they noticed a secretion coming from the tail, which they said resembled milk. Analysis of the substance showed it was rich in lipids and sugars – similar to mammalian milk.

Researcher Marvalee Wake of the University of California at Berkeley suggested that this species of caecilian evolved to deal with a problem human babies also face: The younglings are very vulnerable and can’t fend for themselves, so they need some mother’s milk to grow.

Wake, who was not part of the study, noted this is an example of convergent evolution, a process in which different species can evolve similar traits.

For lead author Marta Antoniazzi, the findings are a reminder of how different species can share commonalities to survive.

“Nature is very creative,” she said. “Sometimes it gives the same solution to different groups of animals.”

This story originally appeared in the April 02, 2024 newsletter, Blazing Furnace.