Red Kangaroo
(macropus rufus)

Geographic Range
Macropus rufus occurs over most of the dry, inland, central part of Australia. This expansive area includes scrubland, shrubland, grassland, and desert habitats.

Habitat
Red kangaroos live over most of the central part of Australia in areas where rainfall averages less than 500 millimeters. They prefer to forage in open plains habitats with neither trees nor bushes, but are seldom found in regions without shade and shelter from scattered trees.

Physical Description
Macropus rufus is the largest living marsupial. Males range in total body length from 1,300 to 1,600 mm and females from 850 to 1,050 mm. Tail length is from 1,000 to 1,200 mm for males and 650 to 850 mm for females. They may weigh as much as 90 kg and may reach 1.8 meters in height when standing. Coat color is usually reddish brown in males and bluish gray in females, although these colors are reversed in some areas, with females being reddish and males blue-gray. Red kangaroos are robustly built, with large, well-muscled tails and powerful hindquarters. The tail is strong enough to support the kangaroo's body weight, acts as a balance when jumping, and is used, with the two legs, to form a tripod for resting. The second and third toes of red kangaroos are fused and shaped into a grooming claw. Their foreshortened upper limbs terminate in clawed paws used with great dexterity in eating, grooming, and self-defense. Females have a forward facing pouch and 4 mammae.

Reproduction
Male red kangaroos compete for mating opportunities with several females. Males will try to monopolize access to several females and will actively drive away other males. This competition sometimes leads to "boxing" matches, where males hit at each other with their forepaws and kick with their feet. There is no permanent association of males and females.

Macropus rufus has a short gestation period. The young are born 33 days after mating, and mating can occur again a day or two after parturition. The fertilized egg resulting from this post-partum mating develops only to the blastocyst stage and then undergoes a period of embryonic diapause. Development is resumed if the previous young, which is still suckling in the pouch, reaches 204 days old or if it dies or is removed. Young kangaroos are known as joeys. Red kangaroo joeys are tiny when born, averaging only 2.5 centimeters long and 0.75 grams. After the joey is born, it crawls up the mother's fur, into her pouch and immediately attaches itself to a nipple. During this period, the sucking stimulus prevents the re-occurence of fertility cycles. Given favorable conditions, a mother red kangaroo produces and raises an average of three young every two years. Individual females often have, simultaneously, a joey outside of the pouch, a joey in the pouch, and a blastocyst awaiting implantation. Compared to the gestation period, the period of lactation is long, about one year in red kangaroos.

A mature female red kangaroo which is appropriately nourished, and which is not suckling a young in its pouch already, becomes fertile at approximately 35 day intervals and is, like the male, potentially fertile throughout the year. Unlike the suckling period, pregnancy does not interrupt recurrence of fertility.
Sexual maturity is reached at 15 to 20 months in females and 20 to 24 months in males, but maturity may be delayed in unfavorable conditions.

Red kangaroo young are tiny when born and make their own way from the birth canal to the pouch and a nipple to which they permanently attach themselves for about 70 days. They are born with well-developed tongues, jaw muscles, nostrils, forelimbs, and digits. Otherwise their external features are embryonic. Females lactate their young for about a year and carry them in their pouch for about 235 days.

Lifespan/Longevity
Lifespans are potentially long in red kangaroos, although most individuals probably do not survive their first year of life. Red kangaroos have been recorded living up to 22 years in the wild.

Behavior
Red kangaroos occur in small groups, averaging 10, called "mobs." These groups are made up mainly of females and their offspring, with one or several males. Females stay within their natal mob. Occasionally, large numbers of red kangaroos congregate in areas of excellent forage, sometimes numbering as much as 1,500 individuals. Red kangaroos are mostly crepuscular and nocturnal, resting in the shade during the day - but have been known to move about during the day. Most of their active period is spent in grazing. Most kangaroo species are relatively sedentary, staying within a relatively well-defined home range. This is also often characteristic of Macropus rufus populations, but they may travel widely in response to adverse environmental conditions. A red kangaroo was recorded traveling 216 km. Population densities have been estimated by two, separate studies at 4.18 individuals per square kilometer and 1 individual per 89 hectares.

Red kangaroo hind legs are powerful and the tail acts to balance the body in a bipedal hop as their legs propel them forwards. Large kangaroos can reach a running speed of 64kph, with leaps as long as 8 meters and as high as 3 meters, although 1.2 to 1.9 meters is more typical of an average pace. Red kangaroos also use their tail an a kind of 5-"legged" gait, where the forelimbs and tail balance the animal as the two rear legs are moved forward simultaneously

Communication and Perception
Little information on communication among red kangaroos is available. Like most mammals, red kangaroos are likely to make extensive use of chemical modes of perception and communication. They also have excellent vision and hearing, suggesting these are important sensory modes.

Food Habits
Red kangaroos are exclusively plant-eaters, with a preferred diet of green herbage including grasses and dicotyledonous flowering plants. These herbivores can go without water for long periods of time by consuming moisture-filled succulent plants.

Predation
Their large size reduces the predation risks faced by red kangaroos. Very young joeys are protected in their mother's pouch and red kangaroos can use their robust legs and clawed feet to defend themselves from attackers with kicks and blows. They may be preyed on by dingo’s and very young joeys, just out of the pouch, may be taken by large raptors. Humans have historically hunted kangaroos for their meat and hides and human hunting continues to be the primary source of predation for red kangaroos.

Ecosystem Roles
Macropus rufus is important in shaping vegetation communities in the ecosystems in which they live through their action as grazers.

Conservation Status
Macropus rufus is not considered endangered. Nearly 3 million square miles of Australian territory now lies within the boundaries of excellent national parks. All Australian states regulate the hunting of kangaroos.

http://animaldiversity.ummz.umich.edu