1. Size: *Hyracotherium* was about the size of a small dog, while *Equus* is much larger.
2. Legs: The legs became longer and more slender, allowing for faster running.
3. Feet: *Hyracotherium* had four toes on its front feet and three on its hind feet, with all toes touching the ground. Over time, the number of toes reduced to one on each foot (the middle toe) – the "hoof".
4. Head: The head became more elongated, with a longer snout.
5. Teeth: The teeth evolved to be adapted for grazing. *Hyracotherium* had low-crowned teeth for browsing on leaves. *Equus* has high-crowned teeth with complex ridges that are ideal for grinding tough grasses.
6. Posture: *Hyracotherium* walked with its body close to the ground, while *Equus* is adapted for running with its legs directly under its body.
These changes occurred gradually over millions of years, driven by environmental changes such as the spread of grasslands and the need to escape predators.
