100 YEARS OLD AND STILL A MODEL OF SLOTHFULNESS...

ONCE upon a time, long, long ago and far, far away, unless you were in South America, all sloths were the same size. Before I continue this evolutionary tale, perhaps I should add some details so that those of you who have not studied sloths in any great detail may be able to put the story into context.

Sloths, you see, have been around for at least 65 million years, which is much longer than humans, so they deserve our respect for that alone. But until about ten thousand years ago, the sloth world was dominated by giant sloths the size of elephants which rampaged around South America and did not hang upside down in trees because that would have been stupid.

Since at least 35 million years ago, however, the giant earth-rampaging sloths had co-existed with much smaller sloths, much like today’s versions of the animal, which did indeed live upside down in the trees. So presumably, some time between 65 and 35 million years ago, all sloths, as I said at the start, were the same size. So let’s get on with the story.

One day, all the sloths gathered for a crisis meeting. “We have a problem,” said their leader. Certain species have evolved, such as giant lions and such, which pose a danger to us. We muse devise an evolutionary strategy to protect ourselves. Any ideas?”

They all sank into thought for a long time, then one meditative sloth came up with an analysis of the options. “It seems to me,” he said, “that we must choose between two options: either we grow big enough to win fights against our predators or at least intimidate them, or we learn to move quickly so that we can run away from them.”

“Good thinking,” said the sloth leader. “Let’s grow big. We don’t want to be seen as runaway cowards.”

Most of the sloths cheered, but one young sloth came up with a third option: “What if we hide?” he asked.

“Explain yourself,” said the leader, so the young sloth did.

“We grow even smaller and hide up trees when predators are near. We’ll just hang there upside down, staying very still and growing algae all over our fur so that no-one can see us. We’ll save energy by not moving, and because we’re so energy efficient, we won’t have to eat much and will only have to climb down the tree once a week or so to pee and poo.”

“Hiding and camouflage?” said the sloths who favoured growing big. “That’s even worse than running away,” but some of the sloths thought the young sloth’s policy of pacifist nonbelligerence made a lot of sense.

So most sloths grew bigger and bigger and rampaged around wherever they wanted, while a small minority hung around in the trees, laughed at by their big brothers and sisters.

But then, after tens of millions of years, humans arrived in South America, and so did climate change, and one or other or both of these wiped out the big sloths. And after shedding tears for their relatives, the little sloths lived happily ever after.

And the moral is: bravery and bigness is all very well, but hiding has a lot to be said for it. Go sloths!