Bird poop: It’s the bane of cars, statues, awnings and occasional hapless pedestrians across the world. But what is this stuff anyway? Why does it look so unnatural? Why is it white?
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Ah, man. Today’s question is pretty gross. OK, let’s give it a go: Have you ever washed a car just to have a bird poop on it a few minutes later?
It’s sad when you think about it. Despite the wealth of technological and social innovations across the span of human history, we still can’t stop birds from flying around, crapping on whatever they want, anywhere, and at any time.
And it’s not even normal poop. It’s white. Sometimes with a dark spot in it.
But why? Why is bird poop white?
Well, the answer here is – it isn’t. At least, bird poop isn’t all white. It’s a mix of colors, and it can vary with the species of the bird or its diet. But there’s definitely white stuff in there.
It all comes down to streamlining. Birds are like any other animal; they take in food, process it for energy and excrete waste. However, where mammals like deer, elephants or Bill Murray have two different excretion systems – urine and feces – bird biology’s all “ain’t nobody got time for that.”
Birds don’t even have separate exits for their waste and reproductive systems – instead of the genitalia/anus combo so popular in the mammalian world, birds have a one-stop shop called the cloaca. It’s the entrance/exit point for the intestines, urinary tract and reproductive system.
Yep. Think about that for a second.
Birds also process the food they eat in a different way. We mammals break down protein and produce nitrogenous waste, but we make it into urea, which we dissolve into water and excrete as urine.
This takes a lot of water, which means we have to drink a lot of it – and also means we don’t do well in places without much water.
Birds take a different approach, and one that conserves water. Instead of dissolving that waste into urine, they primarily excrete something called uric acid – a solid, pasty junk. That’s the white stuff.
In a way, birds aren’t just pooping on our cars, statues, buildings and occasionally very unlucky people looking up with their mouths open. They’re also peeing.
And here’s why – remember how earlier I mentioned this was all about streamlining? Birds aren’t trying to conserve water out of some strange sense of environmental responsibility – they’ve evolved to reduce their weight, and carrying all that extra water around to produce urine just doesn’t make sense.