Why is there so much variation in the poo of herbivores?

Sarah Shailes answered this sticky question from John...

Sarah - It depends on several things really. Firstly it depends on what the herbivores are eating. There are a wide variety of herbivores that are eating all different things.

Fruits and seeds, for example, their nutrients are often easier to access than if you were eating leaves or stems, so the animal doesn’t have to do so much digesting. So that will affect what the poo looks like at the end.

Also, some plants are tougher to digest that other because they’ve got more fibre in them and so you’ll probably land up with more plant material at the other end. There is also chemicals inside some plants that will affect things as well. For example, apricots and prunes contain natural laxatives so if you’re herbivores eating lots of those that might make the poo a bit runnier.

But the other thing that affects it as well is the gut. Herbivores, like all animals, have bacteria in the gut that helps them to digest food and there’s a wide variety of different bacteria that help animals to digest food. That will also have an impact as well.

Chris - John specifically refers to cow pats. What can you say about those?

Sarah - Cows are a herbivore called ruminants, so like sheep as well. The way their guts are organised they have an extra chamber in their stomach called the rumen and that’s where they particularly house their bacteria. As to why cow pats look so different to sheep droppings… I am not entirely sure.

Chris - One vet put it to me once that people think cows eat grass but this is not true. Cows don’t eat grass, cows actually live on a soup of bacteria because they eat grass to feed the bacteria in their guts and the guts grow those bacteria which the cow then digests and it’s all very liquid and runny, isn’t it?