Floating, whether on water or air, sounds pretty appealing, doesn’t it? But floating as a way for whole species to migrate sounds pretty far-fetched. Nonetheless, that’s the conclusion of new research on why Madagascar, the island nation off the east coast of the African continent, has such a range of unique mammal species, all of them on the small side, like lemurs, those petite primates with the long noses and tails. Scientists now think that lemurs and other small mammals “rafted” to Madagascar, today the only place they’re found, about 300 mile across the Indian Ocean from Africa on floating vegetation. This was more than 50 million years ago, and such migrations, accidental or intentional, continued for 30 million years. The flow of ocean currents during back then, unlike now, made such a journey possible.
Matthew Huber, who’s a palaeoclimate modeller (who knew there was such a specialty?) at Purdue University in Indiana, explains: “What the model suggests is that occasionally, say one month in 100 years, the currents were strong enough to allow a raft, for example a large log, carrying a family of lemurs to make the journey in about three weeks.” It’s fascinating to consider this ancient migration route even as climate change is encouraging biologists to explore “assisted migration” for species whose habitats become inhospitable as temperatures shift. But the world’s land masses are far more crowded than they were 50 million years ago. We’re here, after all. If habitat loss or climate shocks required evacuation, and if the currents allowed lemurs to raft again today, would they find a new home? Maybe if they could fly.