How the Lemurs Reached Madagascar

Pygmy mouse lemur

Madagascar is an island. It's quite a large island, to be sure - at nearly 227,000 square miles, it's the fourth largest island in the world, after Greenland, New Guinea, and Borneo. That's nearly twice the size of the UK, or, if you prefer, almost 90% the size of Texas. Even at that size, however, the fact that it's an island has been highly significant for the sorts of animals that live there.

When it comes to islands, the problem for land-dwelling mammals is how they're supposed to get there in the first place. Sure, it's not a problem for bats, which can cross all but the most ridiculous amounts of sea (although not necessarily on purpose!) But, for everything else, it's something of an issue.

Of course, one possibility is that the ancestors of whatever animals we're talking about "were there already". Britain, for example, has been an island since around 6,000 BC, so whatever animals could wander there from the continent before that were already part of the native fauna. True, many of them have been killed off since, which is why we no longer have wild wolves or bears in the UK... but they were there once. And it clearly explains why the various small mammals found on Britain, from red squirrels to harvest mice, badgers, and hedgehogs, are also native to continental Europe. We haven't been an island for that long.