Tag Archives: insular gigantism

Microcosmos

You know what’s been on my mind lately? Midgets. Well, dwarfs. Well, actually, pygmies. I’ve been considering a post about pygmy animals for a while, and as luck would have it, a research team in Borneo just found this miniscule marvel:

Yes, that’s an adult frog. (If it weren’t, it’d be a tadpole, silly.) Measuring only 12 mm, the male Microhyla nepenthicola is the smallest frog in Europe, Africa, or Asia — though, amazingly, there are two species in the Americas that are even tinier. M. nepenthicola‘s species name comes from the Nepenthes pitcher plants it inhabits to keep its skin wet. It might never have been found if it weren’t for its loud, rasping call, which conjures for me an image of a puzzled biologist putting his ear to a pitcher plant like a dog to a Victrola gramophone, wondering why it was croaking.

As megafauna ourselves, I think most humans have this idea that species are trying to evolve to be larger, but are somehow limited. But the fact is that being small has its advantages, and many species are more than willing to become miniaturized to seize the opportunities that can only be found once you breach the microcosmos.

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Only the Lonely

Meet Lonesome George, a subspecies of Galapagos Tortoise.

Galapagos Tortoises are great examples of insular gigantism, the phenomenon by which reptiles, insects, and birds on islands have a tendency to become enormous. (The reverse is true for terrestrial mammals; remind me to tell y’all about the kitten-sized foxes I met while visiting San Nicolas Island off the coast of LA.) Without competition from mammals, the tortoises had as much grass as they could eat, and grew into giants. Like the famous finches and everything else on the Galapagos, the tortoises have branched out into several species over the many islands. George is a Pinta Island Tortoise.

Of course, everything changed when humans found the islands. Goats introduced from the mainland consumed the tortoises’ food supply, and invasive pests attacked them directly. Now Lonesome George is the rarest animal on Earth. He is the only one of his kind.
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