Kangaroos use their tendons like giant springs to hop faster without using extra energy.

Kangaroos utilize a unique biological mechanism known as elastic strain energy. Their massive Achilles tendons act like high-performance springs, storing energy when the animal lands and releasing it to propel the next jump. This process is so efficient that a kangaroo actually uses less energy per hop as it speeds up, a phenomenon rarely seen in the animal kingdom.Research conducted by T.J. Dawson and C.R. Taylor in 1973 published in the journal Nature confirmed that kangaroos do not increase their oxygen consumption when moving faster. This is because the muscles perform isometric contractions, meaning they stay the same length while the tendons do the stretching and recoiling. This mechanical efficiency allows them to travel long distances across the Australian outback in search of food and water without exhaustion.The kangaroo's tail also plays a vital role in this locomotion. It acts as a third leg or a tripod when the animal is stationary and a counterweight during high-speed leaps. At speeds of up to 40 mph (64 km/h), the tail prevents the kangaroo from tipping forward. Additionally, the structure of their pelvic girdle prevents independent leg movement, which is why they cannot walk normally or move in reverse.