A recent study published in the journal Nature Communications, why some animals, like cheetahs, can achieve shocking speeds while others cannot. Led by Dr. David Labonte from Imperial College London, the research team explored the relationship between an animal’s size and its ability to run fast.
Their findings reveal that animals capable of high-speed running tend to be of medium size. Contrary to expectations, it’s not the large elephants or tiny ants that are the fastest, but animals like cheetahs that fall into this intermediate size category.
The study involved developing a model to understand how muscles function during land locomotion and determining the constraints on maximum running speed. It identified two key limits: the speed and distance at which muscles can contract. An animal’s overall size plays a crucial role in determining which limit it encounters first, thus influencing its maximum running speed.
Co-author Professor Christofer Clemente, from the University of the Sunshine Coast and the University of Queensland, explained that animals around the size of a cheetah, roughly 50kg, hit a “sweet spot” where both limits coincide. This makes them the fastest runners, with cheetahs clocking speeds of up to 65 miles per hour.
The study’s model not only elucidates why some animals can run faster than others but also provides insights into muscle evolution and the disparities between animal groups. For example, it explains why large reptiles like crocodiles are slower than large mammals.
Co-author Taylor Dick of the University of Queensland highlighted that reptiles have a smaller percentage of limb muscles compared to mammals, causing them to hit the work limit at a lower body weight and thus limiting their speed.
Dr. Peter Bishop, another co-author from Harvard University, noted that for large animals such as rhinos or elephants, running can feel like lifting an enormous weight due to relatively weaker muscles and increased gravitational demands. Consequently, larger animals are inevitably slower due to these factors.
