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).

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.

[8][9] 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.

[5] 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.

[3] 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.

[3] 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.

[8][9][2] 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.

In the wild, they make firm nests in which to sleep by digging small trenches, using dry grasses and vegetation to line them.

Pygmy hogs are also omnivorous and feed primarily on roots, tubers, and other vegetative food, as well as on insects, rodents, eggs, young birds, and small reptiles.

[12][17] Pygmy hogs also fulfill important ecological roles within their ecosystems, since by using their snouts to dig for food, they not only spread seeds from plants, but they also enhance the quality of the soil.

[17] The pygmy hog is considered to be one of the most threatened mammalian species today, and has been listed as "critically endangered" by the International Union of Conservation (IUCN) since 2008.

Two males and four female individuals were caught under permit in Manas National Park and transferred to a facility in Basistha, where they became the founders of the current captive-breeding program.

[19] Between 2008 and 2016, one hundred captive-bred pygmy hogs have been reintroduced into the wild at three different locations in Assam, these being Sonai Rupai, Orang and Barnadi National Parks.