The red kangaroo (Osphranter rufus) is the largest of all kangaroos, the largest terrestrial mammal native to Australia, and the largest extant marsupial. It is found across mainland Australia, except for the more fertile areas, such as southern Western Australia, the eastern and southeastern coasts, and the rainforests along the northern coast.
Taxonomy
The initial description of the species by A.G. Desmarest was published in 1822. The type location was given as an unknown location west of the Blue Mountains. The author assigned the new species to the genus Kangurus. In 1842, Gould reassigned the species to the genus Osphranter, a taxon later submerged as a subgenus of Macropus. A taxonomic restructure in 2015 in Taxonomy of Australian Mammals by Jackson and Groves promoted Osphranter back to the genus level, redefining the red kangaroo, among others, as a species within the genus Osphranter. This was further supported by genetic analysis in 2019.
Description
This species is a very large kangaroo with long, pointed ears and a square shaped muzzle [snout/nose]. They are sexually dimorphic as the males have short, red-brown fur, fading to pale buff below and on the limbs. Females are smaller than males and are blue-grey with a brown tinge, pale grey below, although arid zone females are coloured more like males. It has two forelimbs with small claws, two muscular hind-limbs, which are used for jumping, and a strong tail which is often used to create a tripod when standing upright.
Males grow up to a head-and-body length of with a tail that adds a further to the total length and are referred to by Australians as "Big Reds". Females are considerably smaller, with a head-and-body length of and tail length of . Females can weigh from , while males typically weigh about twice as much at . The average red kangaroo stands approximately tall to the top of the head in upright posture. Large mature males can stand more than tall, with the largest confirmed one having been around tall and weighed .
The red kangaroo maintains its internal temperature at a point of homeostasis about using a variety of physical, physiological, and behavioural adaptations. These include having an insulating layer of fur, being less active and staying in the shade when temperatures are high, panting, sweating, and licking its forelimbs. They have an exceptional ability to survive in extreme temperatures using a cooling mechanism where they can increase their panting and sweating rates in high temperatures to cool their bodies. To survive in harsh conditions and conserve energy, Red Kangaroos can enter a state of torpor. Red kangaroos also have a high tolerance for consuming plants high in salt content, and can survive for long periods without water by reabsorbing water from their urine in the kidneys, minimizing water loss. They can go for extended periods without drinking, meeting moisture requirements from consumed vegetation.
The red kangaroo's range of vision is approximately 300° (324° with about 25° overlap), due to the position of its eyes.
Locomotion
The red kangaroo's legs work much like a rubber band, with the Achilles tendon stretching as the animal comes down, then releasing its energy to propel the animal up and forward, enabling the characteristic bouncing locomotion. They can reach speeds of around . The males can cover in one leap while reaching heights of , though the average is .