America’s original razorbacks

The stern looking Chacoan Peccary. This is just one of the four surviving species of peccary from a successful group. (Image from here)

Peccaries are a family of superficially pig-like artiodactyls, sometimes erroneously called “wild pigs” or “New World pigs”. Both pigs (Suidae) and peccaries (Tayassuidae) have relatively large heads with a cartilaginous disc at the tip of the rostrum and tough, leathery skin covering the nose and snout for protection during foraging.

Pigs look like peccaries and peccaries look like pigs, but their similarities evolved independently (this is a lovely example of convergent evolution where a different group may evolve similar solutions). There are a number of important anatomical and behavioural differences that differentiate the two (for a full list comparing and contrasting the two, click here). Peccaries are highly social and diurnal animals that can be found in a variety of habitats including arid deserts, dense forests, and open scrublands. All have a stiff bristly coat with an erectile mane running from the back of the head to the rump. A scent gland is located on the rump just above the tail used in mutual grooming and scent marking. They are mostly herbivorous and have a complex two-chambered stomach.

The first of these creatures are known from Europe around 33 million years ago (during the early Oligocene) and spread to Africa and North America. After the Miocene (about 5 million years ago), however, they could only be found in the New World. Their disappearance from the Old World appears to coincide with the diversification of terrestrial primates (the ancestors of today’s baboons and macaques). North America remained a stronghold for these pig-like beasts, and they would advance down to invade South America when the Panamanian Land Bridge formed around 3 million years ago. During the Pleistocene, several types of extinct peccaries coexisted with those species still alive today.

One of the species of peccary arond today, the White-lipped Peccary (Tayassu pecari). (Image from here)

There are three well-known extant species spread across the Americas; the Collared Peccary (Pecari tajacu), White-lipped Peccary (Tayassu pecari), and Chacoan Peccary (Catagonus wagneri). A fourth species, the Giant Peccary (Pecari maximus), was discovered in the Amazon rainforest in 2000. Although its status as a distinct species remains a topic of debate, a study of the mitochondrial DNA reveals that the Giant Peccary diverged from the Collared Peccary between 1.2 million and 860,000 years ago during the late Pleistocene. This ‘new’ peccary also differs from the Collared Peccary in a number of physical and behavioural traits.

The Chacoan Peccary was first described in 1930 from Pleistocene-age fossils and was thought to be long extinct. In 1972 an expedition to the Gran Chaco in Paraguay, led by Dr. Ralph Wetzel,  3 local peccary species were identified that had been recognized by the natives for thousands of years: the Collared Peccary, the White-lipped Peccary, and a larger third species unknown to science at the time but known locally as the “Tagua”. Examination of the animal’s bones revealed it to be the “extinct” peccary which had identified 42 years earlier!

The pretty flat headed peccary, Platygonus compressus. (Art by Aaron Woodruff)

The newly-dubbed Chacoan Peccary was found to be the closest living relative of the extinct Flat-headed Peccary (Platygonus compressus), which lived in North America during the Pleistocene and early Holocene. Indeed, the two are sometimes placed under the same genus. Both of these beasts were specialists, with many features pointing to evolving to life on the open grasslands. They evolved longer, more slender legs for sprinting on open ground with narrow feet for making high-speed turns on rough terrain: these limbs were more like those of a gazelle. They have just two toes on the hindfeet instead of the more conventional three seen in other peccaries. Their long-range vision is more acute, and the eyes are set higher up on the skull, which is  extremely useful when they are feeding from the ground, they can also keep a look out for predators. The teeth are relatively high-crowned to handle the tougher vegetation encountered in dry, open habitats. The snout is deeper to house enlarged sinuses for coping with dry, dusty air.

The longer snouted peccary, Mylohyus nasutus. (Art by Aaron Woodruff)

Living at the same time as the Flat-headed Peccary, the Long-nosed Peccary (Mylohyus nasutus) was a giant by peccary standards, weighing about the same as a sheep. As its common name suggests, its most distinguishing feature was its long, narrow skull which made up over one-third of its total length. Severe lengthening of the snout was achieved by a wide gap between the canines and the premolars. Its legs were very long and it retained four digits on the forefeet and three on the hindfeet.

Flat-headed and Long-nosed Peccaries both lived throughout North America, from New York to California east-to-west and from Canada to Central America north-to-south. Despite their shared range the two seem to have favoured different habitat types; the Flat-headed Peccary occurring in grassland and savannah habitats with suitable bush cover, while Long-nosed Peccaries tended to live in more wooded or forested areas. These habitat preferences are reflected in the teeth and diets of these two species. The strong jaws and robust teeth of the Flat-headed Peccary were designed to process tougher foods found at ground level. Much of its diet would have consisted of grasses, forbs, fruits, and seeds, possibly consuming animal foods on occasion such as insects, small vertebrates, and scavenged meat. Long-nosed Peccaries, meanwhile, has shorter teeth with more rounded cusps, best suited to grinding leaves, flowers, fruits, and twigs. High shoulders, an elongated face, and a flexible neck were adapted to browsing on higher, softer vegetation from overhanging shrubs and trees.

The complete remains of both species are frequently recovered from Pleistocene caves throughout North America, providing much insight into their lives. Given the diurnal nature of today’s peccaries, these caves were most likely used as communal night-time shelters in which individuals would occasionally die of natural causes or be killed by predators. Some baboon troops in Africa will utilize caves in the same way. The presence of Jaguar (Panthera onca) inside many of these peccary caves suggests that, as in modern ecosystems, the fossil peccaries were a favoured prey item for the big cat. Long-nosed Peccary fossils tend to be rarer than those of Flat-headed Peccaries, suggesting that the former lived in smaller social groups while the latter lived in larger communities.

Human artefacts have also been found alongside the peccary fossils at Sheridan Cave in Ohio. This suggests that humans and peccaries were, at times, utilizing the same caves or even competed directly for shelter. Though the relationship that humans may have had with the peccaries is unclear, Pleistocene peccaries would have been well-known to early Americans and these people may have recognized that they shared many traits in common. Like them, these were intensely social, diurnal animals that formed monogamous pairs.

Written by Aaron Woodruff (@CenozoicKing)

Edited by Jan Freedman (@janfreedman)

Further Reading:

Nye, A. S, (2007), “Pleistocene Peccaries from Guy Wilson Cave, Sullivan County, Tennessee”, Electronic Theses and Dissertations. Paper 2115. [Full article]

Roosmalen, M.G.M, et al, (2007), “A New Species of Living Peccary (Mammalia: Tayassuidae) from the Brazilian Amazon”. Bonner zoologische Beitrage 55(2): 105–112. [Abstract only]

Hoare, R, D, et al, (1964), “Pleistocene Peccary Platygonus compressus Leconte from Sandusky County, Ohio”. Ohio Journal of Science: Volume 64, Issue 3: 207-214. [Full article]

Slaughter, B. H ,(1966), “Platygonus compressus and Associated Fauna from the Laubach Cave of Texas”. American Midland Naturalist, Vol. 75, No. 2, 475-494. [Full article]

Wagner, G, (1903), “Observations on Platygonus compressus Leconte”, The Journal of Geology, Vol. 11, No. 8, pp. 777-782. [Full article]