In A Nutshell
Kangaroos and wallabies are very similar marsupials that belong to the same family (Macropodidae) and genus (Macropus). (The above image is a wallaby.) Their native territories often overlap, but wallabies are generally much, much smaller than kangaroos with a color pattern that is much more varied. The lifespan of a kangaroo is much longer, and these larger animals take longer to grow, and become more independent than their relatives.
The Whole Bushel
There are a handful of different subspecies of both wallaby and kangaroo, but the major differences can be applied across the subspecies.
Kangaroos are much, much larger than wallabies. Red kangaroos, a subspecies of kangaroo, is the world’s largest marsupial. The largest individuals, which are always males, can weigh up to 90 kilograms (200 lbs) and stand almost 2 meters (6 ft) tall. Male grey kangaroos are only the slightest bit smaller, while females of both species typically weigh between 40–45 kilograms (88–100 lbs) and are considerably shorter.
In comparison, the average male wallaby only weighs about 20 kilograms (40 lbs), while the female is similarly smaller and typically weighs about 11 kilograms (25 lbs).
Kangaroos tend to be much more long-lived than their smaller relatives. In the wild, the average life span of a kangaroo is 20–25 years, while individuals in captivity only tend to live between 16 and 20 years. (Some individuals in the wild can live up to 30 years, but that’s on the high side.) On the other hand, wild wallabies only live to be between 11 and 15, and the average lifespan in captivity is between 10 and 14 years.
The babies of both are called a joey, and both will have one baby at a time; the mothers carry their young in their pouch until they’re not only weaned, but fully independent. A young wallaby is weaned by the time they are between 7 and 8 months old; they usually stay in their mother’s pouch for a month or so longer, and by the time they are between 12 and 14 months old, they are old enough to breed. Kangaroo babies usually nurse until they are around 9 months old, leave the pouch at 11 months, and are capable of breeding by around 20 months.
Both wallabies and kangaroos live in small family groups called mobs. Mobs are usually made up of a dominant male, his handful of females, their offspring, and occasionally some immature, submissive males. During the time when a female kangaroo has a joey that has been weaned but isn’t fully independent enough to leave her pouch permanently, she usually leaves the mob temporarily until her baby is gone.
Most kangaroos have color patterns that are very evenly distributed over their bodies. Grey kangaroos have colors that fade from darker back to lighter faces and bellies; red kangaroos share much the same pattern, but commonly have white patches on their face, legs and ears. Wallabies tend to be much less monochrome. Agile wallabies have distinctive stripes on their cheeks and hips, and the thick fur of the red-necked wallabies includes red, grey, fawn, dark brown, black, and white.
The ears of a wallaby tend to be proportionately larger than those of a kangaroo. Otherwise, the two species are built very similarly with their powerful, distinctive hind legs and tails forming a tripod while resting. Kangaroos are much more likely to be seen boxing others—usually over mating partners—than wallabies.
Both kangaroos and wallabies have conflicted with human settlers across their native range. There is some competition for forage between the wildlife and domestic animals such as cattle, but as they are herbivores there is seldom other conflict. Humans have hunted kangaroos for their meat and wallabies for their hides, but neither practice is common any more.