Males can be as tall as 2 meters and weigh up to 90 kilograms while females may be three times smaller than males ranging from 71.5 to 110 centimetres and from 18 to 36 kilograms. Not all red Kangaroos are red. Males are usually pale red to brick red but blue-grey males occur. Females are usually blue-grey so they are refereed to as blue fliers. In some areas in Australia, both sexes are reddish.
Red kangaroos are herbivores.
They prefer a diet of herbage such as grasses and plants. In dry seasons, shrubs are also eaten. Feeding takes place mostly at night but may start at late evening and extend into the early evening. The forestomach of the red kangaroo is adapted to digest food rich in cellulose. Red kangaroos can go without water if they have sufficent green food, hence they adapt well to drought and hot weather areas.