Fast Facts:

Red Kangaroo

Special Features

• Male kangaroos are called "boomers', females are "does," and the young are referred to as "joeys".
• Female marsupials have a pouch, or marsupium, in which the young are carried.
• Like all marsupials, kangaroos have two special bones, called marsupial bones, attached to their hip bones. In female kangaroos, the bones serve as an attachment site for abdominal muscles that help strengthen the abdominal wall. Although male kangaroos don't have pouches, they too, have marsupial bones.
• Kangaroos, like many marsupials have a lower basal metabolic rate and therefore lower daily requirements for energy, protein, water, and other nutrients. This means that they can sustain themselves on poorer quality diets of higher fiber content.
• Red kangaroos are known as "foregut fermenters". Their stomach contains microbes (bacteria, etc.) that break down food into absorbable components.
• Kangaroos have extremely powerful hind legs and a very muscular tail adapted for jumping. Large kangaroos can jump nearly 30 feet when they are bounding at full speed.
• Kangaroos can reach speeds up to 40 mph, but cannot maintain high speeds for a long period of time. When moving at slower speeds (around 12 mph), they can hop for hours.
• Red kangaroos have 4 toes on their hind feet. The middle toe is long and has a sharp nail used as a weapon during fights. The 2 inside toes are fused and form a 'grooming claw'. The five claws on their front feet are used as a "comb" for grooming. Male kangaroos also have a scent gland on their chest and often rub bushes, leaving behind their scent.

Social Structure & Behaviors

Kangaroos live in groups called "mobs". Kangaroos will thump the ground with their feet to warn other members of the mob of impending danger, such as a dingo attack.

When male kangaroos fight, they may appear to be 'boxing'. They usually stand up on their hind limbs and attempt to push their opponent off balance by jabbing him or locking forearms. If the fight escalates, they will begin to kick each other. Using their tail to support their weight, they deliver kicks with their powerful hind legs.

Breeding & care of young:
Females become sexually mature at approximately 1.5 years of age; males around 2 years. Red kangaroos are usually fertile year-round and produce young continuously. However, during severe droughts, common in much of Australia, breeding will cease.

Kangaroos may have up to three offspring developing at one time. An embryo can live in the uterus arrested at a stage of development. This is known as embryonic dipause. At the same time, the female may have a second offspring that is carried in the pouch and suckled. (Once the young in the pouch reaches a certain age, the embryo will resume development.) A third offspring may be "at foot".

Kangaroos are able to simultaneously produce two milks of completely different composition. This phenomenon takes place when a birth occurs before the young at foot has been weaned.

Gestation lasts 33 days, after which point red kangaroos are born. When it is born, a red kangaroo is only about the size of a bumblebee! Newborns weigh less than 1/25 of an ounce (less than 0.04 oz.) and measure less than one inch long.

As soon as it is born, the newborn kangaroo, blind and hairless, begins its climb from the birth canal to the safety of the pouch. It crawls 6 inches through the dense fur and attaches to one of its mother's four teats. The journey takes 3 to 30 minutes. This would be the equivalent of a newborn human crawling with its eyes closed ten feet up a steep, grassy hill (Zoobooks).

Having just permanently left the pouch, this offspring will follow its mother outside the pouch. At this rate, a female red kangaroo can give birth every 240 days. Joeys remain in the pouch for 5 to 6 months. After that time, they begin to become more independent. Over a period of 2 to 3 months they gradually spend more time away from the pouch, returning to its safety when they feel threatened. Joeys are usually weaned around 1 year of age. A young kangaroo will usually stay by its mother's side until it is about 1.5 years old.

The female kangaroo has voluntary control over the muscles that control the pouch size and opening. She can contract the muscles, pulling the pouch tight against the body, or relax the opening allowing the joey to fall out.