Some animals like cows can live on grass, so why can't humans? And why do dogs and cats eat it even though they can't live on it either? Learn about digesting grass in this episode of BrainStuff, based on these articles: https://animals.howstuffworks.com/pets/why-do-dogs-and-cats-eat-grass.htm; https://health.howstuffworks.com/human-body/systems/digestive/why-humans-dont-eat-grass.htm