Dire wolf

Dire wolf
Scientific classification
Kingdom Information
Domain	Eukaryota
Kingdom	Animalia
Subkingdom	Bilateria
Branch	Deuterostomia
Phylum Information
Phylum	Chordata
Sub-phylum	Vertebrata
Infraphylum	Gnathostomata
Class Information
Superclass	Tetrapoda
Class	Mammalia
Sub-class	Theriiformes
Infra-class	Holotheria
Order Information
Superorder	Preptotheria
Order	Carnivora
Sub-order	Caniformia
Infraorder	Cynoidea
Family Information
Family	Canidae
Sub-family	Caninae
Tribe Information
Tribe	Canini
Genus Information
Genus	Aenocyon
Species Information
Species	A. dirus
Population statistics
Conservation status	Extinct

The dire wolf (Aenocyon dirus) is an extinct species of large canid, remains of which have been found throughout much of North America. A subject of popular culture, the dire wolf was also given major recognition in the headlines worldwide, as it is apparently the first major animal from prehistory to have been brought back to life via DNA sequencing.

Description

The dire wolf resembled a modern gray wolf (Canis lupus) in its body structure, although it was somewhat larger. The average head-body length was about 4.9 feet, and the weight was approximately 110 pounds. However, due to geographical variations individuals from the western areas reached an average body weight of 74.9 pounds (determined by the length of the femur compared to the modern wolf) and 125.6 pounds (determined by the circumference of the femur). For calculations using the same method, the average values ​​for animals from eastern areas are 92.5 and 149.9 pounds, respectively. This means that dire wolf individuals from eastern populations were, on average, 15% larger than those from the western populations. Both groups are found toward the upper end of the values ​​for the modern wolf, which has an average weight of 88.1 pounds, with variations from 26.4 to 176 pounds.

In contrast to the gray wolf, the dire wolf was somewhat stockier and had shorter yet more powerful limbs. The skull was larger, about 10.5 to 11.1 inches long as compared with gray wolves at about 9.8 inches long. The protruding zygomatic arches (the cheek bones), which were up to 6.8 inches apart, giving it a massive appearance; by comparison, the zygomatic arches of large gray wolves are about 5.39 inches apart. The most striking difference, however, is in the structure of the teeth. The dire wolf had hypercarnivorous dentition, which are simpler than mesocarnivorous dentitions of other canids and primarily retain a cutting function, which is rather rare among the family Canidae and is largely known only from the dhole (Cuon alpinus) or the African wild dog (Lycaon pictus).

Due to the size of the body as compared with its relatively short legs and powerful bite, it was suggested that the dire wolf was a scavenger, living similarly to a hyena and occupying the same ecological niche on the American continent. This theory is supported by strong signs of wear on the animals' teeth. On the other hand, some fossils show healed traumas. According to studies of material from Rancho La Brea, these can be found both in the area of ​​the teeth and on the body skeleton; some are identical to those that modern wolves sometimes suffer in confrontations with particularly large and defensive prey such as moose or elk. It is therefore likely that these animals also actively hunted, much like modern wolves. Based on the body size of dire wolves, it can be concluded that, assuming pack or group hunting, it killed prey in a weight class of 220 to 1,320 pounds.

Subspecies

• Aenocyon dirus dirus
• Aenocyon dirus guildayi

Taxonomy

Since the discovery of the first fossils of dire wolves in 1854, the placement of this animal within a proper genus / species affiliation has been debated for years. The first known find is a nearly complete upper jaw from the banks of the Ohio River near Evansville, Indiana, which was recovered together with the remains of a giant sloth and various ungulates. Joseph Leidy named this upper jaw Canis primaevus in 1854. However, that name had been given earlier by British naturalist Brian Houghton Hodgson in 1833 in reference to the dhole, and therefore could not be used. Leidy decided in 1858 to rename the find from Indiana and chose Canis dirus. Later, several other names were introduced: Canis indianensis (Leidy, 1869) Canis mississippiensis (Allen, 1876) Dinocynops nehringi (Ameghino, 1902) Canis ayersi (Sellards, 1916) and Aenocyon dirus (Merriam, 1918), all of which were accepted alongside each other for a long time, partly due to the sparsity of the fossils on which they are based.

It was not until John Campbell Merriam found a sufficiently complete skeleton in 1912 that the known fragments were recognized as belonging to a single species. According to the valid first description and the rules of zoological nomenclature, the name Canis dirus soon became generally accepted. After further investigations, Merriam found that the differences to other members of the genus Canis were great enough to place the species in a separate genus and proposed the new genus name Aenocyon in 1918, but this view did not prevail at the time. Genetic material from Aenocyon dirus was first obtained in 1992, but it was not further investigated because it was only used for comparison with samples of the saber-toothed cat Smilodon extracted at the same time. It was not until 2021 that scientists re-examined DNA from bones of the species, confirming Merriam's view that the species differs significantly from the genus Canis.

Evolutionary claims

Dire wolf remains have been found in the Late Pleistocene from Alberta, Canada to Peru, with the best-known single site being the Rancho La Brea tar pits in present-day California. Fossils of 3,600 individuals have been unearthed there, more than any other species. According to evolution, the dire wolf evolved on the North American continent. Conventionally, it is generally assumed that it originated from the Armbruster wolf (Canis armbrusteri), which first appeared and spread during the transition from the Early to the Middle Pleistocene about 800,000 years ago, before ultimately becoming extinct. However, it is sometimes believed that it survived in South America, where it became the ancestor of Aenocyon dirus. Aenocyon dirus then originated in South America and from there spread to North America, reaching it about 100,000 years ago. The earliest claimed finds of Aenocyon dirus in North America, however, date to the Middle Pleistocene. During the last ice age, it shared the same habitat as the gray wolf. However, in a period between 13,000 and 11,000 years ago, the dire wolf suffered the same fate as many other animals on the American continent, becoming extinct along with mammoths, American mastodons, short-faced bears, the saber-toothed cat Smilodon, and the giant ground sloths.

Contradicting evolution and related claims, the first step of the Scientific method, direct observation, indicates no evidence of the change in species from Canis armbrusteri into the dire wolf, apart from the personal assumptions made by scientists. Furthermore, the claimed reason for the dire wolf's extinction, the disappearance of large prey animals, also flies in the face of the Scientific method, as the largest animals on the North American continent - bison, caribou, elk, and moose - are routinely observed being hunted by gray wolves.

Dire wolf "resurrection"?

The dire wolf in recent times has become a recognizable animal in popular culture, featured prominently in many documentary species about prehistoric mammals, the La Brea tar pits, and most especially with the television series Game of Thrones

The US company Colossal Biosciences reported in April 2025 that it had "revived" three individuals of the extinct species, born between October 2024 and January 2025, using the CRISPR/Cas method. However, the company only attempted to develop animals that resembled Aenocyon dirus, but in fact they were genetically modified gray wolves.

A total of 14 key genes were modified with 20 mutations to replicate various physical and behavioral characteristics of the dire wolf, including a broader skull and more powerful jaw muscles. For health reasons, the animals were given white fur instead of their original pigmentation. The genetic material was taken from a 72,000-year-old ear bone and a 13,000-year-old tooth.