The evolution of horses could be erroneously depicted as an undeviating straight line progression from the small, terriero (small dog of various breeds) sized Hydracotherium eohippus to the large modem horse, Equus eohippus originated from Eocene period. Eohippus (meaning "dawn horse") was the earliestknown horse. It was the size of a tiny dog. Another name for this genus is Hyracotherium (meaning "mole beast"). Eohippus was only 2 feet \((60 \mathrm{~cm})\) long and 8 to 9 inches \((20 \mathrm{~cm})\) high at the shoulder. This primitive horse had 4 hoofed toes on the front feet and 3 hoofed ant on each hind foot. It had a long skull with 44 longcrowned teeth. Eohippus was a grazing herbivore that ate soft leaves and plant shoots. Eohippus lived during the early Eocene Epoch, about 50 million years ago. The major stages in evolution of horse are : (i) eohippus, (ii)mesohippus, (iii) merychippus, (iv) pliohippus, and (v) equus.