Scaling of neuromuscular delays and reflex time in terrestrial mammals

All animals must effectively sense and respond to their environment in order to survive. Successfully recovering from a stumble, escaping a predator, or catching prey requires quickly detecting changes in the environment and performing appropriate compensatory movements. The speed of an animal’s nerves and muscles constrains its ability to do this. Our work investigates how size-dependent changes in neuromuscular delays affect the reflex times of mammals ranging from shrews to elephants, and how this influences which methods they can use to effectively control their movement. We find that small and large animals are likely challenged by different aspects of their neuromuscular systems, and that total reflex time increases with animal size. Slower movement times in larger animals substantially, but not entirely, offset their longer delays. Neuromuscular delays are likely a challenge for mammals of all sizes, especially when moving quickly.