Burchell's zebra stallions, Rietvlei Nature Reserve, South Africa

It's World Laughter Day!

Although these Burchell’s zebras are probably fighting, it looks like they are having a laugh. Maybe at a classic animal joke: Why did the lion spit out the clown? Because he tasted funny. Or perhaps not. Anyway, World Laughter Day is celebrated on the first Sunday of May to remind people of its very real physical and mental health benefits. Experts (yes, there are experts) agree that laughing lowers blood pressure, releases endorphins, works your abs, reduces stress hormones and even boosts T cells that fight infection. And even if you’re not feeling it, faking it still works.

The Burchell’s zebra is named after William John Burchell, an English naturalist and explorer who, in the early 1800s, travelled extensively in South Africa, studying these and other animals. The Burchell’s zebra is distinguished by one or two faint stripes on its haunches that appear to shadow the bold stripes, but otherwise it strongly resembles other plains zebras. The social structure of Burchell’s zebras is based on a stallion leading a herd of mares - the whole group is called a harem. A young stallion may attempt to lead one of the mares away to his own harem, an effort that may result in a rough confrontation with the resident stallion.