Largest wild pig ever

Based on current fossil evidence, the largest pig of all time is currently (hog) tied between five extinct genera: Kubanochoerus, Nyanzachoerus, Notochoerus, Kolpochoerus and Metridiochoerus. Size estimates made from their skeletal remains indicate that individuals of these prehistoric pigs, dating from between 16 million years ago (MYA) and 700,000 years ago could have stood as tall as 1.2 m (3 ft 11 in) at the shoulder and weighed in the region of 800 and 1,000 kg (1,760 lb–2,200 lb).

Perhaps even larger still were pigs belonging to the genus Kubwachoerus, a cousin of Kubanochoerus found in Africa. One of the largest was K. khinzikebirus, whose fossil remains were discovered in 16-million-year-old deposits from Libya and Kenya. The cheek teeth of K. khinzikebirus exhibit dimensions similar to a hippo’s, and suggest an animal that weighed between 850 and 1,500 kg (1,870–3,300 lb), as large as a modern black rhino. Fossil teeth of an appreciably larger kubanochoere were identified more recently: K. nyakachensis inhabited western Kenya 14 million years ago; its teeth were the size of a small mastodon’s and indicate an animal weighing over 3,200 kg (7,050 lb), on par with a very large white rhino. These estimates, however, merit caution since they were extrapolated based on measurements of the animals’ teeth. Science eagerly awaits more evidence, since skulls and limb bones will allow a much more accurate reconstruction of the beasts’ real-life stature.

Of the kubanochoeres known from more complete remains, the largest was Kubanochoerus gigas, with a conservatively estimated body weight between 800 and 970 kg (1,760–2,140 lb). A common sight across central Eurasia between 16–12 MYA, K. gigas remains are best known from the Caucasus and northern China. The most prodigious feature of its massive, 70-cm-long (2-ft 4-in) skull – for reference, a large Eurasian wild boar skull can reach over 45 cm (1 ft 6 in) long – is a gently down-curved horn protruding from the centre of its forehead, hence how these animals acquired the nickname of "unicorn pigs". Some palaeontologists believe this to be a display trait only sported by males, to attract females and fending off rivals for courtship. It's important to highlight that kubanochoeres are now a fully extinct side branch of the suid family tree.

More closely related to modern pigs (Suidae) than the kubanochoeres, the tetraconodonts were another completely extinct line that approached the larger kubanochoeres in size. The largest tetraconodont species was Nyanzachoerus jaegeri, which inhabited North, East and South Africa between 4.4 and 3.7 MYA. The skull of Ny. jaegeri reached over 64 cm (2 ft) in length, indicating a comparable stature to Kubanochoerus gigas. Just like the giant forest hog of today’s Africa, male Nyanzachoerus sported arched, knob-like protrusions from its cheekbones, which may have served display purpose. Notochoerus euilus, a possible descendant species from Ny. jaegeri, also far-exceeded the size of modern pigs. Remains found in Kenya and Ethiopia, from deposits 3.8–2.6 million years old, indicate an animal that stood 1.2 m (3 ft 11 in) at the shoulder, with a skull up to 62 cm (2 ft) long. Evolution in the Nyanzachoerus-Notochoerus lineage between 5 and 1.7 MYA was characterized by continuous evolution in dental structure through time, for adaptation towards chewing on the tough grassy vegetation of the emerging African savannah ecosystem. Such is the signal for continuity through time, that some palaeontologists place Ny. jaegeri at the base of the Notochoerus series, as Notochoerus jaegeri, instead of treating it as the terminal species of the Nyanzachoerus genus.

Other more fragmentary partial skulls from the nearby Konso area in southern Ethiopia indicate even larger Kolpochoerus specimens. According to Dr Antoine Souron (University of Bordeaux), these fossil remains indicate a formidable hog which could weigh over 1 tonne (2,200 lb). K. paiceae lived between 1.5 million and 800,000 years ago, with fossil remains found from Israel to South Africa. Unlike its forest-dwelling cousin, K. paiceae fossils have often been found alongside typical savannah species from African straight-tusked elephants (Palaeoloxodon recki) to the extinct giant-horned African buffaloes (Syncerus antiquus), indicating a preference for more open habitats.

Today’s warthogs are nondescript-sized savannah dwellers, but it too can recall a more gigantic phase in its family history. Metridiochoerus compactus was a giant warthog found in East and South Africa between 1.92 million and 700,000 years ago. The tusks are often more than 30 cm (12 in) in length, and can be mistaken for those of extinct elephants during palaeontological field excavation work. Unfortunately few remains that permit accurate body size reconstruction are known for the giant warthog, but a conservative estimate falls in the area around 800 kg (1,760 lb).

With the justified exception of abnormally large domestic pigs, the title for the biggest pig today is a close run-in between the Northern Eurasian wild boar (Sus scrofa) and the East African giant forest hog (Hylochoerus meinertzhageni), the latter found in the forests surrounding Lake Victoria in Uganda, the Kenya highlands and northern Tanzania. Largest individuals of both species can typically weigh in at 275 kg (606 lb). Yet evidently, they would be dwarfed by some truly gigantic hogs from Earth’s deep past.