Sus salvanius
SUBFAMILY
Suinae
TAXONOMY
Sus salvanius (Hodgson, 1847), Sikkim Terai, India.
OTHER COMMON NAMES
French: Sanglier nain; German: Zwergwildschwein; Spanish: Jabalí enano.
PHYSICAL CHARACTERISTICS
Length 20–28 in (50–71 cm); shoulder height 10–12 in (25–30 cm); weight 14.5–21 lb (6.6–9.7 kg). Aside from its smaller size, the only diagnostic characters of this species are its vestigial tail and the presence of only three pairs of mammae in females. This species has no facial warts. The hair is agoutibanded and medium brown along the sides of the animal, darkening along the back. Piglets are faintly striped at two to four weeks of age. The tusks of males are exposed, whereas those of females are not.
DISTRIBUTION
Now only found in a few isolated populations in Manas Tiger Reserve in northwest Assam, making it the rarest suid in the world.
HABITAT
Found only in tall grassland habitats associated with early successional riverine communities. Those grasslands dominated by Narenga porphyrocoma, Saccharum spontaneum, S. bengalensis, S. munja, Erianthus ravennae, Imperata cylindrica, and Themeda spp. are the most important for pygmy hogs.
BEHAVIOR
The main social groupings are sounders containing one or more adult females and their offspring and solitary males.
Unique among the suids in that it builds nests year round, which are made of grass leaves and built over shallow depressions in the ground. Both sexes and all age classes use nests on a nightly basis.
FEEDING ECOLOGY AND DIET
Omnivorous, feeding on roots, tubers, grass leaves, shoots, fruits, seeds, insects, worms, eggs, and small vertebrates.
REPRODUCTIVE BIOLOGY
Polygamous. Males will associate with estrous sows during the rut. Reproduction is highly seasonal with breeding beginning in late November and early December. Breeding may continue into the spring in captivity. Females are in estrus for three to four days during the 21-day cycle, and gestation lasts 120 days. In the wild, there is a clearly defined birth peak from April–June. Litters average around four piglets (range two to seven), weighing approximately 5.3 oz (150 g) at birth. Females are sexually mature at 20 months, whereas males reach maturity at two to three years of age. In captivity, both sexes reach sexual maturity at 10–11 months.
CONSERVATION STATUS
Considered Critically Endangered by the IUCN and is listed on Appendix I of CITES, as well as on Schedule 1 of the Indian Wildlife Protection Act of 1972. Also considered endangered by the U. S. Fish and Wildlife Service. The main threats are loss and degradation of habitat because of human settlements, agriculture, flood control schemes, and improper management. Tree planting in grasslands and the use of fire to open up grasslands for new growth have been detrimental. Hunting is becoming more of a threat. The survival is closely linked to the existence of the tall, wet grasslands. A conservation program was launched in 1995 as a cooperative effort among the IUCN/SSC Pigs, Peccaries, and Hippos Specialist group, the Durrell Wildlife Conservation Trust, the Forest Department (Government of Assam) and the Ministry of Environment and Forests (Government of India), and includes captive breeding, field research, and reintroduction.
SIGNIFICANCE TO HUMANS
Though they are not crop pests, hunting of pygmy hogs for meat is increasing. Their small size makes it a potentially very useful and valuable genetic resource for biomedical research and further domestication.
