Kangaroos Hopping: Why Kangaroos Jump

Photo: Two kangaroos hopping across the Australian Outback

Kangaroos have a unique way of moving — they hop! Unlike most animals that walk or run, kangaroos use their large, powerful hind legs and large feet to bounce along the ground. This special way of moving is fast and very energy-efficient, and allows them to travel long distances without getting tired. The Red Kangaroo, for example, usually hops at a speed of about 20-25 km/h. But it can accelerate to phenomenal speeds of up to 70 km/h (44 mph) in just a few hops and maintain this speed over long distances. A single hop from a kangaroo can cover up to 8 meters! Kangaroos are the only large animals in the world that move in this way.

How Kangaroos Hops - The Mechanics of Hopping

When a kangaroo hops, its muscular hind legs compress in a synchronised spring-like motion, bringing its toes towards its body. This functions like a spring being compressed. Then its toes move away from its body, and it bounces up like a spring being released. The concept is similar to how a Pogo Stick works.

While hopping, it gets its bounce from its Achilles tendons in the back of its legs. These tendons and associated ligaments act like giant stretching and shrinking rubber bands. When its legs compress, its tendons get stretched. Then the energy stored in the stretched tendon – referred to as elastic potential energy – together with contracting muscles, start pulling the bottom part of its legs downwards, giving the animal a springing bounce back into the air. By using gravity and its weight to work its springy tendons, a kangaroo is estimated to use 40% less energy than a comparable four-legged animal.

Advantages of Hopping - Why Kangaroos Hop?

Kangaroo Hopping is Super Efficient

At speeds above 6km/h, a kangaroo actually uses less and less energy as its speed increases. At speeds above 18kph, a hopping kangaroo uses less energy than any other animal of equivalent weight. If a foxhound were to chase a kangaroo, it would consume twice as much energy and would tire out in less than 2 kilometres. The kangaroo, on the other hand, could go another 20 kilometres and still seems as fresh as when it started.

Kangaroo Hopping is Silent

Kangaroos move extremely quietly compared to other animals. You would hardly notice a mob of kangaroos whooshing silently past you at top speed. An equivalent number of deer, which are similar in body sizes, would create quite a loud racket. The reason for this is that the kangaroo's soft padded feet, relatively small footprint, and the fact the only two feet touch the ground.

Excellent Speed Control

Kangaroos increase their speed by increasing the length of their hops—not the frequency of hops. When it wants to go slow it takes small hops. When it wants to go fast it takes large hops. All other animals increase the speed of each step—with only a very small increase in their stride.

How Fast Can a Kangaroo Go?

The fastest kangaroo is the red kangaroo. It has been recorded at speeds of up to 70kph. At this speed each of its "strides" is as much as 8 meters apart. (The record is an astonishing 13 meters). Because hopping is super-efficient, it can also maintain this speed for a long time without exhausting itself.

A Kangaroo Can 'Turn on a Dime'

Because the kangaroo uses bi-pedal (two legs like humans) locomotion, it can easily pivot on one foot and rapidly change direction. It is claimed that it can make a 180 degree turn in a single hop. Four-legged animals with their relatively long bodies cannot turn as rapidly.

A Kangaroo Can't Move Backwards

A Kangaroo can make very limited hops backwards when fighting. It cannot actually do so as a means of locomotion.

A Kangaroo Can't Walk

A Kangaroo cannot walk forward or backwards by moving its legs independently. The kangaroo can, however, move its legs independently it just can't do so for walking.

A Kangaroo Can't Move its Legs Independently

A kangaroo can move its legs independently when required, but while hopping kangaroos usually move both hind legs together. The independent movement of its legs occurs when the animal is turning while it is hopping when it places one leg slightly in front of the other to execute a turn. When it uses its feet in 'foot thumping' to warn other kangaroos of danger and when swimming.

How High Can a Kangaroo Jump?

The red kangaroo can jump as high as 3m (3.3ft). It holds the high jump record.

Hopping Doesn't Work Well at Slow Speeds

At low speeds, however, a kangaroo is far less agile. Its super-efficient hopping legs let it down. (See next section to learn how a kangaroo moves at slow speeds).

Does the Kangaroo have an Fifth Leg?

Yes—its tail! The kangaroo can't hop at slow speeds. So it uses pentapedaling locomotion; where it uses its tail as an additional leg.

A kangaroo moves at low speeds by leaning forward on to its short front limbs, hoisting itself up with its tail and then shifting its hind legs forward. This method of movement is called 'pentapedal' (four limbs + tail) locomotion. Only the kangaroo does this. Recent research has shown that the kangaroo's tail with its 20 vertebrae, acts like a fifth limb fulfilling the role of a normal leg. In this role it is capable of generating more forward force than all of the kangaroo's other limbs combined.

Learn More About Australia’s Wildlife

• Complete Guide to Marsupials →
• Difference Between Marsupials and Mammals →
• More Australian Animals to Discover →