Is it ever OK to poop on yourself? This bird sure thinks so
Marabou Storks living in dry, hot southern Africa have evolved to poop on their legs in order to stay cool
Meet the Marabou Stork:
They’re not going to win any beauty pageants anytime soon. Not only are they quite an unfortunate sight to behold - with their bare head and neck, their evil-looking large beak, their dangling gular sac and their too-skinny legs - they also have the habit of defecating onto their own legs.
But there’s a legitimate reason for their smelly antics: Marabou Storks live in hot, dry areas and are generally found a distance away from water. The natural colour of their legs - dark legs are also inefficient for cooling the body.
What they’ve adapted to do, instead, is ‘urinate’ a white excretion of uric acid on their dark-coloured legs. (Take a closer look at the image above again: the stork pictured here has black legs that have already been covered in a white layer of uric acid!)
Unrelated, but why are Marabou Storks so ugly?
Marabou Storks seem to resemble a dead or dying creature. That’s because your mum was right when she said “you are what you eat!”
These birds are scavengers, and will eat anything from carcasses of flamingoes and small birds and mammals, to human refuse and even dead elephants. But because they are always around dead and decaying matter, they have evolved to have bald heads in order to reduce the risk of infections.
Think about it: sticking one's head into a carcass isn't the most hygienic thing in the world, so the Marabou stork developed bare heads to prevent blistering and catching + harboring bacteria.
These large, dangly pouches also serve a function: the marabou stork doesn’t have a voice box, and cannot sing, caw or chirp! What they can do, though, is make a loud croaking sound by using its throat pouch, or a loud clattering by clapping its bills together.
The process of ‘urinating’ on their legs is called urohydrosis, and other birds do it too
The using of excrement to cool the body isn’t unique to the Marabou Stork. The process is called urohydrosis.
Once they defecate on their legs, that liquid evaporates, and it cools the bird’s legs - much like our sweat helps cool our skin. It also adds a preventative measure our sweat doesn’t, since as the dribbled waste dries, it leaves behind the white powdery solids of the waste, which can then reflect sunlight and keep the legs from getting quite too hot.
Another bird species that adopts this practice is the Turkey Vulture, pictured above. Like the Marabou Stork, they have evolved to have featherless legs and heads in order to minimise the risk of infection when scavenging from carcasses. But since their legs don’t have the benefit of sun protection from feathers, they too must practice the cooling method known as urohydrosis!
Aren’t birds cool? Even when they seem ‘gross’, there’s a reason for it. Subscribe, and continue along on this journey to learn more about birds with me!