Platygonus were gregarious animals and, like modern peccaries, possibly traveled in herds. At least nine known species of Platygonus are known and ranged from southern Canada to Mexico and from California to Pennsylvania. Stratigraphically, they occur throughout the Pleistocene (Calabrian), and as early as the Blancan in the Gelasian of the Pliocene. The most recent credible date obtained for some species remains is about 11,000 BP.
Platygonus was named by Leconte (1848). It was assigned to Tayassuidae by Le Conte (1848), Hoare et al. (1964) and Carroll (1988).
Most Platygonus species were larger than modern peccaries, at around 1 m (3.3 ft) in body length, and had long legs, allowing them to run well. They also had a pig-like snout and long tusks which were probably used to fend off predators. They had a complex digestive system, similar to that of a modern ruminant.
Four specimens were examined by M. Mendoza for body mass, with the following estimations on weight:
- Specimen 1: 133.1 kg (290 lb)
- Specimen 2: 162 kg (360 lb)
- Specimen 3: 131 kg (290 lb)
- Specimen 4: 116.6 kg (260 lb)