Speaker 1: Welcome to brain stuff from how stuff works. Hey, brain stuff,
Speaker 1: it's Christian Seger. Today's question is pretty gross. Okay, let's
Speaker 1: give it a go. Have you ever washed a car
Speaker 1: just to have a bird poop on it a few
Speaker 1: minutes later? It's sad when you think about it. Despite
Speaker 1: the wealth of technological and social innovations across the span
Speaker 1: of human history, we still can't stop birds from flying
Speaker 1: around crapping on whatever they want anytime anywhere. A bird
Speaker 1: actually pooped on my dog's head the other day. And look,
Speaker 1: this is not normal poop. It's white, sometimes with a
Speaker 1: dark spot in it. But why why is bird poop white? Well,
Speaker 1: the answer here is it isn't. At least, bird poop
Speaker 1: isn't all white. It's a mix of colors, and it
Speaker 1: can vary with the species of the bird or its diet,
Speaker 1: but there's definitely white stuff in there. Right. Well, it
Speaker 1: all comes down to streamlining. Birds are like any other animal.
Speaker 1: They take in food, process it for energy, and excrete waste. However,
Speaker 1: where mammals like deer elephants or bill murray have two
Speaker 1: different excretion systems like urine and feces, bird biology ain't
Speaker 1: got time for that birds don't even have separate exits
Speaker 1: for their waste and reproductive systems. Instead of the genitalia
Speaker 1: anous combo so popular in the mammalion world, birds have
Speaker 1: a one stop shop called the cloaca. It's the entrance
Speaker 1: exit point for the intestines, urinary tract, and reproductive system. Yep,
Speaker 1: think about that for a second. Birds also process the
Speaker 1: food they eat in a different way. We mammals break
Speaker 1: down protein and produce nitrogenous waste, but we make it
Speaker 1: into urea, which we dissolve into water and excrete as urine.
Speaker 1: This takes a lot of water, which means we have
Speaker 1: to drink lots of it and also means we don't
Speaker 1: do well in places without much water. Birds take a
Speaker 1: different approach, and one that conserves water. Instead of dissolving
Speaker 1: that waste into urine, they primarily excrete something called uric acid.
Speaker 1: It's a solid, pasty junk that's the white stuff. In
Speaker 1: a way, birds aren't just pooping on our cars, statues, buildings,
Speaker 1: and occasionally very unlucky people looking up with their mouths open.
Speaker 1: They're also peeing. And here's why. Remember how earlier I
Speaker 1: mentioned this was all about streamlining. Birds aren't trying to
Speaker 1: conserve water out of some strange sense of environmental responsibility.
Speaker 1: They've evolved to reduce their weight and carrying all that
Speaker 1: extra water around to produce urine. It just doesn't make sense.
Speaker 1: There are also, and I can't believe I'm saying this
Speaker 1: pros and cons to bird poop. Pro it's a great fertilizer.
Speaker 1: Con it can carry a wealth of diseases. Also, it's
Speaker 1: been used as a cosmetic of facial cleanser. True story. Well,
Speaker 1: if it's a pro or con, that's up to you.
Speaker 1: Check out the brainstuff channel on YouTube, and for more
Speaker 1: on this and thousands of other topics, visit how stuff
Speaker 1: works dot com.