Although their diets vary by location, all kangaroos follow an herbivore diet, meaning that they only eat plants. Some common dietary staples include leaves, shoots, grasses and shrubs.
Because the plants they eat are rich in moisture, kangaroos are able to go prolonged periods of time without drinking water. Droughts may be harmful for kangaroos, as a lack of water causes their food sources to dissipate.
Before completely swallowing plant matter, kangaroos regurgitate it and then chew it a second time as cud. Their stomachs have chambers similar to those of cows and sheep, which helps them digest plants. Unlike other ruminants, kangaroos barely release any methane gas, despite having similar digestive systems and diets.
Kangaroos have teeth that are uniquely adapted for efficient grazing. Their molars break down grass, and their incisors allow them to eat grass down to the ground. Kangaroos have a wide bite due to the location of their lower incisors. Grazing quickly wears the teeth out, which causes the front molars to fall out regularly. Kangaroos have teeth that grow in the back of their mouths, which replace the front molars as they fall out. Manatees and elephants are the only other animals capable of this process.