Cheetahs are the ultimate sprinters among large land animals, reaching bursts of up to about 110 kph (~68mph) and unbeaten as the fastest living runner on the planet. This beautifully re-articulated skeleton reveals some of the ways they are able to reach such superhuman speeds. The sigmoidal curve of the spine visible in this image allows the front and hind limbs to overlap, meaning that every stride can be longer as the spring-like backbone extends and contracts. The secret behind this springiness is spinal flexibility, with each vertebra having considerable freedom of movement. The movement of the hind limbs around the pelvis is also highly flexible, and the elongated ischium of the pelvis means the attached leg muscles can produce more moment (turning force) around the joint with every step. Contrary to the idea that lighter, leaner animals make faster runners, the cheetah’s hindlimbs are strong, heavy and powerful – which is one reason why they can produce such impressive acceleration and speed, but not maintain it over long distances (like a powerful car in a low gear).
Cheetahs and their hunts are a key focus of the Structure and Motion Lab at the Royal Veterinary College, using bespoke tracking collars to gather never before seen data about both the hunters and their prey. To read more about the Structure and Motion Lab’s work on cheetahs, see here.
Image courtesy of Patrick Gries. See more of Patrick’s series of re-posed skeleton photos here.
Ischium: The rearmost of the three bones which make up the pelvis; the main bone you sit upon.
Moment: Turning force (or torque) around a point. The longer the lever (such as the ischium in this case), the more movement can be generated by the same applied force.