The pygmy hog is the smallest pig species in the world — standing just 25 centimetres (9.8 in) at the shoulder. It is also one of the rarest. Once widespread across the southern foothills of the Himalayas, fewer than 250 mature individuals now survive, confined to a small patch of grassland in Assam, India. 

A male Visayan warty pig can become four times larger than a female. During mating season, the male uses his tusks for combat and three pairs of warty growths on his face for defence — he also grows a 23 cm (9 in) long mane to attract females. The species is only found on two Philippine islands.