They only come out at night. They have fingers like E.T. and tails plump with stored-up fat. They’re so tiny, you’d only need a single Forever Stamp to mail one anywhere in the continental United States.
Despite being actual, real-world animals, mouse lemurs have two super powers that put Pokémon to shame. The first is a disproportionate amount of chutzpah for a critter whose skull looks small next to a blackberry.
“Mouse lemurs are tiny, but they are fierce,” said Anne Yoder, who has handled her fair share of the world’s smallest primates as director of the Duke Lemur Center in Durham, N.C. “Bare skin anywhere near a mouse lemur is ill-advised.”
And all that teeny tiny violence isn’t reserved for humans. Yoder, who is also a professor at Duke, says that males have to be swiftly removed from female company after mating has occurred, lest “the female has the chance to bite his face off.”
A study published Monday in the Proceedings of the National Academy of Sciences reveals a second super power for the little critters: It turns out that if you collect a small dab of blood from enough wild mouse lemurs, you can open a scientific portal that lets you travel into the past.
I know what you’re thinking: Let’s use the mouse lemur blood to assassinate baby Hitler.
First of all, that’s a dicier proposition than you might think. And second, mouse lemur blood magic doesn’t work like that.
Here’s the skinny: Yoder and her colleagues collected DNA samples from five mouse lemur species that inhabit various parts of Madagascar. Then, using a relatively new technology called RADseq, they sequenced each of those samples and compared them to each other to find out how closely related each mouse lemur species is, how long ago they diverged, where each species used to live geographically and whether those species still inhabit their ancestral home. With all that data in front of them, they can paint a picture of lemur populations long past — and by doing so, they give themselves a window into the evolution of different ecosystems.
For instance, Yoder has long been troubled by two mouse lemur species in particular. The brown mouse lemur (Microcebus rufus) lives in the humid forests of Madagascar’s southeast, while Madame Berthe’s mouse lemur (M. berthae) scuttles about the dry forests on the west side of the island. The species are separated by around 250 miles of wide-open grasslands, which might as well be the Red Waste for a tree-dwelling creature such as a mouse lemur. And yet, an earlier study by Yoder revealed M. rufus and M. berthae to be bewilderingly close cousins.
“For the past 15 years, I have been worrying about how the heck it was possible that a species on the east could be so much more closely related to a species on the west than it was to all of its nearest neighbors,” Yoder said.
But data from the new study may just solve the mystery — and settle another long-standing, seemingly unrelated dispute.
Today, many estimate that Madagascar’s forest cover is just 10 percent of what it was before humans arrived some 2,000 years ago. Some argue that the island was a lush, forested Eden in pre-colonization days. Others contend that the sparsely forested Central Highlands are a natural relic of the island’s historical savanna grassland interior.
But neither of these hypotheses hold up if you look at the mouse lemur DNA.
According to Yoder’s analysis, M. rufus and M. berthae diverged from a common ancestor some 50,000 years ago. There would be no good reason for this divergence if the island was, until recently, one solid block of green. Similarly, if the east and west have been historically separated by unyielding savanna, then Yoder would expect a divergence to the tune of millions of years, rather than tens of thousands.
“Though there can be no doubt that human activities have profoundly altered the natural environment, it actually seems that the natural environment was already less than entirely hospitable to forest-dwelling creatures, being a mosaic of grasslands and woodlands long before humans arrived,” she said.
One of the other weird things about mouse lemurs is that while there are two dozen species alive today, many of them look and behave quite similarly to one another. Yoder suspects that this is because they are extremely responsive to environmental changes and that this has been the driving force behind the crazy branching on the mouse lemur family tree. This also makes our tiny, tree-clutching cousins important for investigating the impacts of modern climate change.
By the way, if you wanted to catch a mouse lemur, you wouldn’t need a magical Poké Ball. You just need a little fruit.
“It turns out that mouse lemurs will do just about anything for a piece of banana,” said Yoder. They can even become what she calls "trap happy." But catching mouse lemurs is not recommended. For one, nearly every species of mouse lemur has a spot on the International Union for Conservation of Nature’s Red List. They also might just bite your face off.
Jason Bittel writes about weird animals for a living. You can find more of his work at his website.