Long or short gut

The idea

The length of the small intestine depends on diet: herbivores eating grass need a longer small intestine to digest cellulose, while carnivores, whose meat is easier to digest, have a shorter one.

Cow and tiger

A cow eats grass. A tiger eats meat.

Whose small intestine do you think is longer?

• The grass-eater's
• The tiger's
• They are exactly equal

Pick a diet

Choose each diet and watch the small intestine in the picture. The bar is a model, not a measurement.

Diet decides the length

The length of the small intestine is not the same in all animals. It depends on what they eat. Grass has cellulose, which takes longer to digest, so herbivores eating grass need a longer small intestine. Meat is easier to digest, so carnivores such as tigers have a shorter one.

The length of the small intestine depends on diet: herbivores eating grass need a longer small intestine to digest cellulose, while carnivores, whose meat is easier to digest, have a shorter one.

Notes

The small intestine's length depends on diet: longer in herbivores eating grass (to digest cellulose), shorter in carnivores (meat is easier to digest).

Check yourself

Which animal needs a longer small intestine?

Why do herbivores eating grass need a longer small intestine?

A tiger eats meat. Compared with a grass-eater, its small intestine is ...

• A carnivore such as a tiger. Meat is easier to digest, so carnivores like tigers have a shorter small intestine.
• A herbivore eating grass — correct. Yes!
• Both need the same length. The length differs in various animals depending on the food they eat.
• Because grass is easier to digest than meat. Meat is easier to digest than grass, which holds cellulose.
• Because grass has no cellulose. Grass does contain cellulose, and that is why a longer small intestine is needed to digest it.
• To allow the cellulose to be digested — correct. Yes!
• shorter, because meat is easier to digest — correct. Yes!
• longer, because meat has cellulose. Cellulose is in grass, not in meat. That is why grass-eaters need a longer small intestine.
• the same, because all animals digest alike. The length of the small intestine differs in various animals depending on their food.