Red Kangaroo
The red kangaroo (Osphranter rufus) is the largest marsupial on Earth and a true icon of the Australian outback. Males grow much bigger than females and wear a rich reddish coat, while females are smaller and bluish grey. Both sexes travel in loose social groups called mobs, grazing on grasses and shrubs across open plains and arid landscapes. Their hind legs act like springs, storing energy in elastic tendons and releasing it with each powerful bound. This makes hopping surprisingly efficient at speed, far cheaper in terms of energy than running is for most mammals. To handle the intense heat of the interior, red kangaroos rest in the shade during the hottest part of the day and become more active in the cooler hours around dusk and dawn. They get much of their water from the plants they eat, allowing them to go for long periods without drinking.
What is a red kangaroo?
The red kangaroo is the largest kangaroo and the largest marsupial alive today, a grazing animal of the open plains of inland Australia. Like all marsupials, the female carries her young in a pouch, and like all kangaroos it moves by hopping on its huge back legs. It was described for science in 1822 by the French zoologist Anselme Desmarest, and for most of the twentieth century it was known as Macropus rufus, a name that still appears in many books and zoos. In 2015 its genus, Osphranter, was raised again to full rank, and genetic studies published in 2019 backed the change, so today its scientific name is Osphranter rufus. The word rufus means reddish in Latin and refers to the coat of the males. Its closest relatives are the wallaroos and the antilopine kangaroo, which share the same genus, while the grey kangaroos of the east and south belong to a different one.
How big is a red kangaroo?
Red kangaroos show one of the biggest size differences between the sexes of any mammal. A large male can measure up to 1.4 meters from nose to the base of the tail, plus a tail of up to 1 meter, and weigh as much as 92 kilograms. Standing in a normal resting position he is about 1.5 meters tall, and when he rises up on his toes and tail to fight or look around he can approach 1.8 to 2 meters. Females are much lighter, usually reaching no more than 39 kilograms, less than half the weight of a big male. The names of the species also come from color. Males are usually brick red, while females are often blue grey, which is why Australians call them blue flyers, although there are grey males and red females too. Both sexes have a pale belly and a black and white mark on each side of the muzzle. Males keep growing for most of their lives, so the biggest animals in a mob are usually the oldest males.
Where does the red kangaroo live?
The red kangaroo lives only in Australia, and it is found across most of the dry interior of the continent, which makes it one of the most widespread large mammals in the country. It favors open grasslands, shrublands and lightly wooded plains where it can see far and grass grows after rain. The arid and dry zones of the interior are its stronghold, including much of the outback of Queensland, New South Wales, South Australia, Western Australia and the Northern Territory, and a small number reach the northwest of Victoria. It avoids the wet forests of the coast, the far north and the cooler southeast, where the grey kangaroos live instead. In the heat of the day red kangaroos rest in the shade of trees and bushes, often scraping a shallow bed in the soil. When drought dries out one area, mobs can travel long distances toward places where rain has fallen, so the number of animals in any one region can change a lot from one year to the next.
What do red kangaroos eat?
Grass makes up the bulk of the red kangaroo's diet, with a strong preference for the green shoots that appear after rain. When fresh grass is scarce, it also eats flowering plants, small herbs and the leaves of shrubs to meet its needs. Like a cow, it has a large stomach where bacteria ferment tough plant material, and it sometimes brings food back up to chew it again, so it can live on dry forage that would be too poor for many other large grazers. One of its most remarkable abilities is getting enough water from the plants it eats to go for long periods without drinking, which matters a lot in the outback, where surface water can disappear for months. It feeds mostly in the cooler hours, from late afternoon through the night until early morning, and rests in the shade during the hottest part of the day. On farms, red kangaroos also graze on pasture and drink from the water points made for cattle and sheep.
How fast can a red kangaroo hop?
Few animals move quite like the red kangaroo. At speed it travels only by hopping, using long elastic tendons in its back legs that work like springs. Energy is stored when the feet hit the ground and released again with the next bound, so once it is moving fast, hopping costs it surprisingly little energy compared with running for most mammals of a similar size. At a comfortable cruising pace a red kangaroo moves at around 20 to 25 kilometers per hour, and it can keep that up for a long time. In short bursts it can pass 55 kilometers per hour, cover about 7.5 to 8 meters in a single leap and clear fences close to 1.8 meters high. When it moves slowly while grazing it does something different: it leans on its front legs and its thick tail, which works almost like a fifth leg, and swings both back legs forward together. A red kangaroo cannot move its back legs one at a time on land, although it does kick them separately when it swims.
Mobs and social life
Red kangaroos live in loose groups known as mobs, which usually include one or more big males, several females and young animals of different ages. Membership is flexible: animals come and go freely, and the makeup of a group can change a lot from one week to the next, while in good seasons several small groups may gather on the same green pasture. Most mobs are small, often fewer than ten animals. The dominant male, called a boomer, is usually the largest animal around and has priority access to females that are ready to breed. Females are called flyers or does, and the young are joeys. Young males that have left their mothers often spend time together on the edges of bigger groups, testing their strength in play fights. Red kangaroos communicate with body postures, soft clicking sounds and a loud thump of the back feet on the ground to warn others of danger, a signal that carries clearly across open country.
Why do red kangaroos box?
Among male red kangaroos, fighting is a regular part of life, and it is the reason for their famous muscles. Rivals size each other up before a contest begins, standing tall on their toes and tail to show their full height and bulk, and sometimes pulling at grass or scratching their chest to show off. When a fight breaks out, the males grapple with their forelimbs, push and grab at each other's head and shoulders, and then lean back on their tail to deliver powerful kicks with both hind feet at once. These kicks can cause serious injury, and the thick skin of the belly gives adult males some protection. Most contests are about which male gets to mate with a female that is ready to breed, and the winner is usually the bigger, heavier animal. Because males keep growing and fighting all their lives, old boomers develop huge arms and chests. Young males rarely challenge a well established boomer directly, but they practice in play fights for years before they try.
How do red kangaroos reproduce?
Red kangaroos can breed at any time of year when there is enough food, which helps them recover quickly after a drought. The pregnancy lasts only about 33 days, and the newborn joey is tiny, about the size of a jellybean. It climbs through its mother's fur into the pouch, attaches to a teat and keeps growing there for months. It first pokes its head out at around six months and leaves the pouch for good at about eight months, but it keeps coming back to drink milk until it is close to a year old. The female's system is remarkable. Soon after giving birth she can mate again, and the new embryo stops developing and waits while the pouch is busy. When the older joey leaves, the embryo starts growing again. So a female can have a young at foot, a joey in the pouch and a waiting embryo at the same time, and she even produces two different kinds of milk from two teats for the two young. In a bad drought she stops breeding until the rains return.
How many red kangaroos are there?
The IUCN lists the red kangaroo as Least Concern, and it is still one of the most common large animals in Australia, with a population of several million. Nobody counts every animal, but each state surveys the areas where commercial harvesting is allowed from the air, and the numbers show how much they change with the weather. The 2023 survey in New South Wales counted about 2.9 million red kangaroos, and South Australia's 2024 survey estimated close to 3 million in its harvest areas, while Western Australia counted about 609,000 in 2024. Good rains bring a jump in food and breeding, and long droughts can cut numbers sharply in just a couple of years. The species has in some ways benefited from farming, since water points for livestock let it live in places that used to be too dry. Commercial harvesting for meat and leather is legal in several states, with yearly quotas set from these surveys, and in most years the harvest stays well below the quota.
