What Is the Biggest Kangaroo? Size, Weight, and Range

The red kangaroo (Macropus rufus) is the biggest kangaroo alive today and the largest living marsupial on Earth. A fully grown male can stand roughly 1.5 to 1.8 meters tall and weigh anywhere from about 55 to 90 kilograms, with exceptional individuals reportedly tipping past that range. But the story of kangaroo size goes well beyond today’s species, stretching back to Pleistocene giants that were nearly three times heavier and may not have hopped at all.

How Big Red Kangaroos Get

Red kangaroos are built for the vast, dry interior of Australia, and their bodies reflect it. Males are the ones that reach headline-grabbing sizes. A large adult male stands as tall as a person, with a long, thick tail that can add another meter of length behind the body. Their bodies are lean and muscular, with notably powerful hind legs and a deep chest.

Females, by contrast, are considerably smaller. A typical adult female red kangaroo weighs roughly a third of what a big male weighs. This size gap is among the most extreme in the mammal world and is not just a curiosity. It shapes nearly everything about how kangaroos mate, fight, and survive.

The eastern grey kangaroo (Macropus giganteus) often gets confused with the red kangaroo as the “biggest” because its species name literally means “giant.” Eastern greys are indeed large, with males reaching around 50 to 66 kilograms, and they’re the most commonly encountered kangaroo in eastern Australia. But they fall consistently short of large male red kangaroos in both weight and height.

Why Males Are So Much Bigger Than Females

The size difference between male and female kangaroos is driven by sexual selection. In kangaroo society, males compete physically for mating access. They box, grapple, and kick, and the bigger, stronger males win more often. Over evolutionary time, that pressure has pushed males to grow larger, especially in the forelimbs and upper body.

Research across 15 kangaroo and wallaby species has confirmed that the largest species show the strongest dimorphism in upper-limb build. As species get bigger, males develop disproportionately longer humeri, the upper arm bones used in wrestling bouts. It is the relative length of the humerus that becomes increasingly exaggerated with body size, not the forearm bone as researchers once thought.

1Journal of Zoology. Strong arm tactics: sexual dimorphism in macropodid limb proportions

The western grey kangaroo illustrates the extreme end of this pattern. Males in that species show indeterminate growth, meaning they keep getting bigger throughout their lives rather than reaching a fixed adult size, and can eventually reach up to six times the body mass of females.

2Biological Journal of the Linnean Society. Is there evidence for a trade-off between sperm competition traits and forelimb muscularity in the western grey kangaroo?

Red kangaroos follow a similar pattern. A dominant male in his prime is a strikingly different animal from a young male or any female. His shoulders are thick, his forearms look swollen with muscle, and his reddish-brown fur is noticeably darker. These males invest so much energy in competition that their body condition fluctuates with drought and reproductive activity in ways that smaller individuals do not experience as strongly.

Range and Habitat

Red kangaroos occupy a massive swathe of inland Australia. Their range covers the arid and semi-arid zones across most of the continent, essentially everything except the coastal fringes, the tropical north, and the extreme southwest. They prefer open grasslands and shrublands where they can see approaching threats and move freely.

Their distribution is not static. Red kangaroos shift their concentration in response to rainfall and drought. Aerial surveys across more than 200,000 square kilometers in South Australia over a 26-year period showed that during dry times, red kangaroos became more spatially aggregated, clustering in areas where food and water remained available.

3Journal of Applied Ecology. Spatial patterns of kangaroo density across the South Australian pastoral zone over 26 years: aggregation during drought and suggestions of long distance movement

Western grey kangaroos, which share part of the same range, did not show this drought-driven clumping to the same degree, suggesting that red kangaroos respond more dynamically to changing conditions.

Eastern grey kangaroos, meanwhile, dominate the wetter, more temperate and subtropical coastal regions. Genetic research has revealed surprising structure within the species, including a distinct population along the Sunshine Coast in southeastern Queensland that is genetically divergent from both the northern and southern populations.

4PLOS ONE. Phylogeography of Eastern Grey Kangaroos, Macropus giganteus, Suggests a Mesic Refugium in Eastern Australia

That kind of hidden diversity matters for conservation and for understanding how landscape barriers have shaped populations over thousands of years.

How Other Large Kangaroo Species Compare

Australia has four species commonly referred to as “kangaroos” in the strict sense, all belonging to the genus Macropus. Beyond the red and eastern grey, the western grey kangaroo (Macropus fuliginosus) is a robust, stocky species found across southern Australia. Males can weigh up to about 54 kilograms, placing them as the third largest. They tend to live in scrubby woodland and are more tolerant of drier southern climates than eastern greys.

The antilopine wallaroo (Macropus antilopinus) rounds out the group. It is a large kangaroo endemic to the tropical savannas of northern Australia, from the Kimberley through the Top End and into northern Queensland.

5ResearchOnline. The ecology and conservation of the antilopine wallaroo (Macropus antilopinus)

Males can reach about 50 kilograms. The antilopine wallaroo occupies an ecological niche similar to the red kangaroo’s but in a hotter, more humid landscape, and the two species have almost no geographic overlap.

Beyond these four, there are wallaroos (like the common wallaroo, Macropus robustus) and dozens of wallaby species, but these are meaningfully smaller. Even the largest wallaroo males rarely exceed 45 to 50 kilograms. The red kangaroo stands alone as the heavyweight.

The Biggest Kangaroo That Ever Lived

If you expand the question beyond living species, the answer shifts dramatically. The largest kangaroo ever was Procoptodon goliah, a short-faced sthenurine kangaroo that lived during the Pleistocene. Researchers estimate its body mass at around 240 to 250 kilograms, almost three times the size of the largest living kangaroos.

6PLOS ONE. Locomotion in Extinct Giant Kangaroos: Were Sthenurines Hop-Less Monsters?

Procoptodon goliah was not alone. The Pleistocene was home to an entire radiation of large sthenurine kangaroos, and researchers have developed body mass estimates for at least 11 extinct megafaunal kangaroo species using measurements of their fossilized thighbones.

7Australian Journal of Zoology. Ecological and evolutionary significance of sizes of giant extinct kangaroos

Several of these species weighed well over 100 kilograms. For context, that puts them in the range of a large adult male human, and some were far heavier.

These animals did not appear out of nowhere. Fossil records through the Oligo-Miocene show a statistically significant increase in body mass across kangaroo lineages over millions of years. Many ancestral kangaroo genera went extinct in the Middle Miocene and were replaced by larger sthenurine species around the time of a major climate warming period.

8Palaeogeography, Palaeoclimatology, Palaeoecology. Species abundance, richness and body size evolution of kangaroos (Marsupialia: Macropodiformes) throughout the Oligo-Miocene of Australia

Large body size evolved multiple times independently in the kangaroo family tree, coinciding with the expansion of open woodland habitats starting in the Late Miocene.

9Systematic Biology. Reconstructing the Evolution of Giant Extinct Kangaroos: Comparing the Utility of DNA, Morphology, and Total Evidence

An intriguing footnote from that same evolutionary analysis: the closest living relative of the once-diverse sthenurine kangaroo radiation is not a kangaroo at all in the popular sense. It is the banded hare-wallaby (Lagostrophus fasciatus), a small, endangered species weighing about two kilograms, now confined to two islands off western Australia.

9Systematic Biology. Reconstructing the Evolution of Giant Extinct Kangaroos: Comparing the Utility of DNA, Morphology, and Total Evidence

Could Prehistoric Giant Kangaroos Actually Hop?

This is one of the more contested questions in Australian paleobiology. A kangaroo the size of Procoptodon goliah presents a real mechanical challenge. Hopping is energy-efficient for living kangaroos largely because of elastic energy stored in their tendons, but as body size increases, the stress on those tendons rises steeply. Earlier scaling analyses suggested that at around 140 to 160 kilograms, kangaroo tendons would approach safety-factor limits that would make hopping dangerous or impossible.

10PubMed Central. Hind limb scaling of kangaroos and wallabies (superfamily Macropodoidea): implications for hopping performance, safety factor and elastic savings

Extrapolations from those scaling data predict that Procoptodon goliah, at 250 kilograms, would have had a tendon safety factor below one, meaning its tendons would literally be expected to rupture during hopping, especially during acceleration.

6PLOS ONE. Locomotion in Extinct Giant Kangaroos: Were Sthenurines Hop-Less Monsters?

So what did they do instead? Anatomical evidence from their hind limbs, particularly features suggesting weight-bearing on one leg at a time, has led researchers to propose that derived sthenurine kangaroos used bipedal striding. Think of it as walking upright on two legs, more like a person than like a hopping kangaroo. Studies comparing foot bone structure between the most derived sthenurines and modern kangaroo species found pronounced differences consistent with this idea.

11PubMed Central. Divergent locomotor evolution in “giant” kangaroos: Evidence from foot bone bending resistances and microanatomy

However, more recent work has pushed back on the idea that hopping was flatly impossible. A 2025 study directly examined the fossil hind limb bones of giant kangaroos rather than relying on extrapolations from modern species. The researchers found that the metatarsals of giant kangaroos could resist the bending forces involved in hopping, and their heel bones could accommodate tendons large enough to handle hopping loads.

12PubMed Central. Biomechanical limits of hopping in the hindlimbs of giant extinct kangaroos

The debate is far from settled, but it is increasingly clear that extrapolating from living kangaroo anatomy may underestimate what the extinct giants were actually built to do.

How Size Shapes the Way Kangaroos Move

Living kangaroos use two fundamentally different gaits depending on their speed, and size plays a role in both. At high speeds, kangaroos hop. Their hind limb tendons act like springs, storing and releasing elastic energy with each bound. Remarkably, hopping kangaroos show very little increase in their rate of energy expenditure as they speed up, unlike most running animals, which burn more fuel at higher speeds.

13bioRxiv. Postural adaptations may contribute to the unique locomotor energetics seen in hopping kangaroos

Recent research suggests that changes in hind limb posture, how the kangaroo positions its legs during a hop, contribute to this efficiency by increasing tendon stress and allowing more elastic energy storage at faster speeds. But this mechanism comes with a trade-off: higher tendon stress means larger kangaroos are closer to the breaking point, which may be one reason no living kangaroo exceeds about 90 kilograms.

At slow speeds, kangaroos switch to something entirely different. They plant their tail on the ground in sequence with their front and hind legs, using what researchers call pentapedal locomotion: walking on five “legs.” The tail is not just a passive balance aid. It generates as much propulsive force as the front and hind legs combined, and produces almost exclusively positive mechanical power, performing about as much work per unit of body mass as a human leg does during walking.

14PubMed Central. The kangaroo’s tail propels and powers pentapedal locomotion

The tail functions, in a precise biomechanical sense, as a true leg: it both supports body weight and provides forward thrust.

15Journal of Experimental Biology. The kangaroo’s fifth leg

Pentapedal locomotion is characterized by a specific sequence: the tail repositions forward, then holds the ground while the hind legs swing through. The pelvis stays at a roughly constant height throughout, so the animal is not bouncing up and down but gliding forward in a smooth, efficient stride.

16Australian Journal of Zoology. Walking on five legs: investigating tail use during slow gait in kangaroos and wallabies

For a large red kangaroo male, whose muscular tail can be as thick as a human thigh at the base, this system is an impressive piece of biological engineering.

Keeping Cool at Large Size

Being big in the Australian outback means dealing with extreme heat. Red kangaroos have evolved a thermoregulation strategy that relies heavily on evaporative cooling, but they split the task differently from eastern grey kangaroos.

At very high temperatures, around 45°C, both species depend on evaporative heat loss to keep their body temperature stable. Both pant and lick their forearms, where a dense network of blood vessels runs close to the surface. Eastern grey kangaroos rely on panting for about three-quarters of their evaporative cooling, with licking making up a smaller share. Red kangaroos also rely primarily on panting, but cutaneous evaporative heat loss, mostly through forearm licking, accounts for a much larger proportion, roughly 40 percent of the total.

17PubMed. Thermoregulation by kangaroos from mesic and arid habitats: influence of temperature on routes of heat loss in eastern grey kangaroos (Macropus giganteus) and red kangaroos (Macropus rufus)

The forearm licking strategy works because blood flow to the forelimbs increases dramatically in the heat. Measurements in red kangaroos showed that forelimb blood flow rose by anywhere from about 60 percent to more than 300 percent when exposed to high temperatures, and these increases were highly consistent across individuals.

18Comparative Biochemistry and Physiology Part A Physiology. Forelimb blood-flow and saliva spreading in thermoregulation of Red Kangaroo, Megaleia rufa

By spreading saliva on the skin above these engorged vessels, the evaporating moisture pulls heat directly from the blood. It is a simple but remarkably effective system, and it helps explain why red kangaroos can thrive in places where daytime temperatures routinely exceed 40°C.

How Many Kangaroos Are There

Kangaroo populations in Australia are enormous by the standards of large wild mammals anywhere in the world. In New South Wales alone, aerial surveys in 2017 estimated roughly 17.5 million kangaroos across the state’s 14 commercial harvest zones. More than half of those, about 9.3 million, were eastern grey kangaroos. Red kangaroos were most concentrated in the far west, with the Tibooburra zone holding the highest count at about 1.6 million.

19Australian Zoologist. Four decades of research and monitoring the populations of kangaroos in New South Wales: one of the best long-term datasets in Australia

These numbers fluctuate substantially with rainfall and drought cycles. After a run of good rains, kangaroo populations can surge, only to crash when conditions turn dry. Australia manages kangaroo numbers through a regulated commercial harvest, with quotas set at between 15 and 17 percent of the estimated population. In practice, the actual take is far below that ceiling. In 2017, only about 455,000 were taken in New South Wales, representing just 2.6 percent of the total estimated population.

19Australian Zoologist. Four decades of research and monitoring the populations of kangaroos in New South Wales: one of the best long-term datasets in Australia

The sheer abundance of kangaroos is sometimes used to argue that they do not need conservation attention, but that overlooks species-level differences. Red kangaroos and eastern greys are abundant, but the antilopine wallaroo has a more restricted range and faces pressure from habitat change in northern savannas. And for the banded hare-wallaby, the last surviving kin of the great sthenurine giants, the population is measured in the low thousands on just two small islands. Size and abundance do not always go hand in hand, and the kangaroo family tree holds species at both extremes.