As herbivores that lack any serious natural predators, kangaroos participate in very simple food chains composed of themselves, their grass-like food and the scavengers and decomposers that eat them. Humans historically hunted and killed many kangaroos, but they are relatively safe from unarmed predators.
Because they consume vegetation directly, kangaroos are considered by scientists to be primary consumers. Kangaroos are grazers that share similar diets with the large ungulates of North America. They primarily consume grasses, but they will eat forbs and herbs as well. In captivity, kangaroos may accept fruit, but this is not part of their diet in the wild.
Dingoes occasionally hunt and eat kangaroos, but this is not a common occurrence. Kangaroos are blessed with great speed and a fierce disposition; few predators are capable of catching them or are foolish enough to fight them. However, once kangaroos die, like all other organisms, they are consumed by scavenging and decomposing organisms. Vultures, rats and insects scavenge the bodies of the dead kangaroos after they die. Shortly thereafter, decomposers in the form of earthworms, fungi and bacteria break down the cells of the kangaroos. This liberates the resources in the kangaroo’s body so that plants can use them to fuel their growth.