Axis porcinus, or hog deer, is a medium-size cervid: it is much smaller than the sambar Cervus unicolor and considerably larger than most species of muntjac, for example the red muntjac Muntiacus muntjak.

This endangered species once ranged widely in South Asia and Southeast Asia, however its range is now greatly fragmented, and the species is likely to be extinct in many former territories.

There is a likelihood that Axis porcinus represents at least two separate species, however, as of 2019, the taxonomy appears unresolved. Some researchers use the genus Hyelaphus, rather than Axis, for this species. Local names for the species include 'Thai hog deer' and 'Indochina hog deer'.

In the field, the hog deer can be identified by its relatively short legs in comparison to body size, and its rich brown winter fur, which becomes greyish in the summer. Fur colour along the dorsal line is darker, and the belly is pale. Juveniles of some populations have rows of small, pale spots - these may still be visible in some adults. Males have slender antlers, which have a short projection at the base, and which fork into two tines at the tip.

In Thailand, where the species has been locally reintroduced, herds of 'several dozen individuals' once inhabited alluvial or riparian plains, especially where there were tall grasses. IUCN summarizes their diet as including 'young grasses, particularly Imperata cylindrica, Saccharum spp ... it also takes herbs, flowers, fruits ... young leaves and shoots'.

Hunting pressure and conversion of grassland habitat for agricultural uses has contributed to the decline of this species, which probably now only occurs in two countries of Southeast Asia, namely Thailand (reintroduced) and Cambodia. It is probably extinct in Myanmar, Laos and Vietnam.

Outside the region it still occurs in Pakistan, India, Nepal, Bhutan and Bangladesh, but is probably extinct in China.