Although javelinas (peccaries) are very similar in appearance to wild pigs, they are a completely different species. How do they differ?

Javelina (collared peccaries), and pigs (swine) are members of the order Artiodactyla, suborder Suiformes, sharing a common ancestry dating back some 30 million years. But, because of significant anatomical and genetic differences they, have been placed in separate families - pigs in the Suidae family and Javelina in the Tayassuidae.

Tayassuids are pig-like animals that are found in the southwestern United States, south to central Argentina. All species have contrasting areas of white or yellowish fur on their chests, backs, or faces. Each of the three species is currently placed in its own genus: Catagonus wagneri, Pecari tajacu and Tayassu pecari. Tayassuids are known in the fossil record from all continents except Antarctica and Australia.

The collared peccary (Tayassu tajacu), commonly known as the javelina, is found as far south as Argentina and as far north as Texas, New Mexico, and Arizona. Collared peccaries are in the even-toed, hoofed mammal order of Artiodactyla. Javelina are mistaken for pigs, but they are in a different family than pigs. There are several differences between the two animals, detailed below:

Javelina:
three toes on the hind foot
bones are fused in the foot
ulna and radius " lower arm bones" are fused
38 teeth
canine teeth are straight
have scent glands
have complex stomach
lack a gall bladder
have a short tail
lack sweat glands

Pigs:
four toes on the hind foot
bones in the foot are not fused
ulna and radius are not fused
34 or 44 teeth
canine teeth are curved
lack scent glands
have a simple stomach
gall bladder is present
have a long tail
have sweat glands