Some animals eat it, some navigate by it, others use it to find a mate - but to most of us, it's just a huge, stinking pile of dung.
But now a new exhibition at the Natural History Museum in Tring, Hertfordshire, "Poo: a natural history of the unmentionable" is encouraging us to take a closer look at faecal matter.
A range of cheerful cartoons, smelly displays and real-life specimens are accompanied by a smattering of faecal facts. For example, cave-dwelling bats rain down so much poo that research scientists can ski on it. Visitors can also study the solitary genet, a small cat-like mammal which uses its droppings as a lonely hearts ad, signalling that it wants to mate. (Don't try this at home.) Paul Kitching, education officer, said: "Poo has a definite yuck factor.
But it is scientifically valuable. We want people to appreciate the wealth of information that can be gathered from droppings."
For example, taking a tip from Hansel and Gretel, the hippo leaves a trail of dung whenever it leaves the river to snack on nearby grassland. At night, it merely follows the smell back home.
Many facts are included in an illustrated children's book to accompany the exhibition. Neal Layton, co-author, said:"We don't ever sit down and discuss poo, so people don't realise how useful it is."
But Eleanor Johansson, six, from Twickenham, west London, was unimpressed.
She said: "Poo is yucky and slimy. I wouldn't want to look at it too closely, and I won't be thinking about science when I go to the toilet."
Poo: a natural history of the unmentionable runs from August 3 to November 28. www.nhm.ac.ukmuseumtring