Pygmy hog

The pygmy hog (Porcula salvania) is a very small and endangered species of pig and the only species in the genus Porcula. Endemic to India, the pygmy hog is a suid native of the alluvial grasslands in the foothills of the Himalayas, at elevations of up to 300 m (980 ft). Populations of pygmy hogs were once widespread in the tall, dense, wet grasslands in a narrow belt of the southern Himalayan foothills from north-western Uttar Pradesh to Assam, through southern Nepal and North Bengal, and possibly extending into contiguous habitats in southern Bhutan. Due to human encroachment and destruction of the pygmy hogs' natural habitat, the species was thought to have gone extinct in the early 1960s. However, in 1971, a small pygmy hog population was rediscovered as they were fleeing a fire near the Barnadi Wildlife Sanctuary in Assam. Today, the only known population of pygmy hogs resides in Manas National Park in Assam, India. The population is threatened by livestock grazing, fires and poaching. With an estimated population of less than 250 mature individuals, the pygmy hog is listed as an Endangered species on the IUCN Red List, and conservation efforts such as captive breeding and re-release programs are currently being employed.

Porcula salvania was the scientific name proposed by Brian Houghton Hodgson in 1847 who described a pygmy hog from the Sikkim Terai. Hodgson argued that the pygmy hog was a genus separate from Sus based upon its unique morphological differences, particularly pertaining to its skull and dental features. Hodgson's classification of the pygmy hog as a separate genus was challenged with the argument that the pygmy hog's unique physical characteristics were "superficial" and merely a result of its small body size, therefore deeming these features insufficient to warrant separate distinction from other members of the genus Sus. Its species epithet salvania is after the sal forests where the pygmy hog was found. Although the decision was not unanimous, the pygmy hog was later determined to be a member of the genus Sus and was renamed Sus salvanius.

A 2007 genetic analysis of the variation in three mitochondrial DNA loci, combined with rigorous statistical testing of other phylogenetic hypotheses, confirmed Hodgson's original classification that the pygmy hog is a separate and distinct genus from Sus. The analysis also showed that the pygmy hog had never clustered with the wild boar or any other Sus species. Based upon this genetic analysis and resulting evidence, the pygmy hog has again been re-classified as its own unique genus Porcula, which is a sister lineage of Sus. Genome analyses support the independence of Porcula.

The skin of the pygmy hog is a grayish-brown color, and its coat consists of blackish-brown bristles. Its irises are hazel brown, and it usually has no facial warts. Its head is sharply tapered with a slight crest of hair on the forehead and on the back of the neck. It has well-developed teeth, with upturned canines and molars with rounded cusps. Adult males have the upper canines visible on the sides of their mouths.

As suggested by its name, the pygmy hog differs from other members of the Suidae by the extreme reduction of its body size, and it is the smallest pig species. An adult pygmy hog weighs between 6.6 and 9.7 kg (15 and 21 lb), with the average male weighing about 8.5 kg (19 lb). From its hoof to its shoulder, the pygmy hog ranges from about 20–25 cm (7.9–9.8 in) tall and is about 55–71 cm (22–28 in) long. While females are only slightly smaller than males, both sexes have tails approximately 2.5 cm (0.98 in) long.

The pygmy hog is endemic to northeast India and was once widespread in the tall, wet grasslands of the Terai from Uttar Pradesh through Nepal to Bangladesh, northern West Bengal and Assam. It inhabited early successional riverine grasslands dominated by Imperata cylindrica, Saccharum munja, S. spontaneum, S. bengalenis, Themeda villosa and Narenga porphyrocoma. In its most pristine state, these grasslands were intermixed with a wide variety of herbaceous plants and early colonizing shrubs and young trees. Growing up to 1–4 m (3 ft 3 in – 13 ft 1 in) in height, these grass species were maintained by periodic burning, which posed a great threat to the pygmy hog. Since these grass species were also commercially important thatching grasses, they were harvested annually, thereby also causing great disruption to the pygmy hog habitat.

The pygmy hog is currently on the verge of extinction. By 2002, the only viable population, consisting of only a few hundred individuals, lived in small grassland pockets of Manas National Park in Assam and in an adjacent reserve forest in the Manas Tiger Reserve. In 2013, it was estimated that only about 250 pygmy hogs existed.

Pygmy hogs are social animals that live in small family groups consisting of one or two females and their offspring. They are non-territorial, and sometimes family groups can consist of as many as 20 individuals. Adult males are generally solitary and live separately rather than with the family group. However, they do maintain loose contact with the basic family group throughout the year.