Have you ever heard an eerie howl in the distance late at night? Hopefully, that sound stays at a distance because it could be a wolf! There are two species of wolf alive today, the gray wolf (Canis lupus) and the red wolf (Canis rufus). There is one subspecies of red wolf alive today and there are 38 subspecies of gray wolf across North America and Eurasia. What about species thousands or even millions of years ago? Would the same wolves we hear today be howling back then? This article will investigate exactly that and introduce 3 extinct wolf species.
What are Wolves?
Wolves are a canid species in the same family as coyotes, foxes, jackals, domestic dogs, and many extinct species. They all belong to the family Canidae, the dog-like carnivores. This family is the subfamily of canines that are alive today and includes the genus Canis which describes wolves, coyotes, dogs, and golden jackals.
Modern gray wolves (Canis lupus) earn their name from their typically thick gray coat. Depending on their location, their coats may also include darker or lighter grays, whites, browns, or ochre shades. They have dense winter coats that are suitable for cold habitats. This dense fur is shed seasonally during the spring and grows back before winter.
Gray wolves are the largest of their genus and on average weigh 88 pounds; however, there is substantial variation geographically. In North America, the average gray wolf is 79 pounds, in Europe, they average 85 pounds, and in India and the Arabian Peninsula, they are smaller at 55 pounds. Especially large wolves are on record in Alaska, Canada, and Russia exceeding 100 pounds, but this is rare. The largest wolf ever documented was found in Alaska and weighed 175 pounds!
The red wolf (Canis rufus) is an intermediate species between coyotes and gray wolves. Red wolves are usually smaller than gray wolves but can weigh between 50 and 85 pounds. They live in the southeastern United States and can be identified by their distinctive reddish fur.
The red wolf is currently a critically endangered species. Efforts following the Endangered Species Act of 1973 by the U.S Fish and Wildlife Service sought to prevent the extinction of the red wolf. Captive breeding programs at Point Defiance Zoo in Tacoma, Washington were active components of these efforts but low genetic diversity in the breeding individuals was problematic. The red wolf has been classified as critically endangered since 1996 and the IUCN reports its population is trending down.
The gray wolf globally has a stable population with the IUCN designation of least concern. Wolves have a Holarctic geographic distribution. This means that they inhabit areas broadly spread across the Northern Hemisphere. They live throughout Eurasia and North America but are locally extinct in much of their western European range and are no longer in Ireland, the United Kingdom, or Japan.
In The United States, gray wolves have an interesting conservation history specifically in Yellowstone National Park. By the 1920s, there were no wolves left in Yellowstone due to hunting pressures and governmental actions. By eliminating wolves and other carnivores, elk populations were left unchecked by their predators and grew tremendously. The increase in elk consequently had massive effects on local vegetation, and then consequently on other herbivore populations. This series of events is called a trophic cascade- when one key species is removed from an ecosystem and causes a cascade of effects down the food web. In this scenario, the wolves of Yellowstone are the keystone species that are crucial to the stability of their entire ecosystem. In 1995 and 1996, 14 Canadian wolves and 10 wolves were captured and transported to Yellowstone. The wolf population in Yellowstone has been growing ever since.
What are Conservation Statuses?
The conservation statuses of various animal and plant species are assessed by the International Union for the Conservation of Nature (the IUCN) and added to their “Red List”. The IUCN evaluates different species and assigns them to one of the following categories on the IUCN Red List: data deficient, least concern, near threatened, vulnerable, endangered, critically endangered, extinct in the wild, and extinct. These categories are distinguished by a set of criteria that grade the level of endangerment of a species. Animals and plants at the lowest risk for extinction are “least concern” and those at high risk are “critically endangered”. The IUCN also tracks if certain populations are trending upwards or downwards in total size. Other organizations that track various endangered species are the U.S Department of Fish and Wildlife, the World Wildlife Fund, and more. With this background knowledge, let’s meet 3 extinct wolf species!
1. Dire Wolf (Aenocyon dirus)
The first extinct wolf species we will investigate is one of the most recognizable extinct mammal species, the dire wolf (Aenocyon dirus). The dire wolf was alive between 125,000 and 9,500 years ago and was a contemporary competing predator with other famous extinct mammals such as the saber-tooth cat, the short-face bear, and the American lion. They could inhabit diverse habitat types including grasslands, forests, plains, and some mountainous areas. Their fossil record spans North America, South America, east Asia, and potentially elsewhere in Eurasia.
The dire wolf became extinct during the Quaternary extinction event approximately 12,700 years ago. During this extinction event, 90 genera (groups of related species) of large predators weighing over 97 pounds became extinct. The cause of this mass extinction event is still a topic of hot debate, but contributing factors likely include climatic change at the time, the extinction of an herbivorous prey many of the predators relied upon, and exploitation by human hunters.
This extinct wolf species wasn’t very similar in size to any modern wolves. The dire wolf’s average shoulder height was approximately 3 feet 2 inches, however there is ample evidence that there were larger individuals as well. For comparison, the average shoulder height range of a modern Northwestern wolf, the largest living subspecies of gray wolf, is between 2 feet 3 inches and 3 feet. Also, scientists predict dire wolves could have been 150 pounds or more. This is much larger than the average wolves we see in the wild today that weigh up to 88 pounds on average. Although it was larger, the dire wolf was proportionally similar to the present-day Yukon wolf and Northwestern wolf.
Interestingly, the dire wolf is considered to have very advanced dental characteristics even in comparison to living species. A study of bite forces in different predatory mammals, while adjusting for total body mass, found that canine teeth bite forces were greatest in dire wolves. Dire wolves had very prominent and strong canine teeth, even more so than gray wolves today.
2. The Japanese Wolf (Canis lupus hodophilax)
The next extinct wolf species we will discuss is the Japanese wolf (Canis lupus hodophilax). The Japanese wolf was first described by scientists in 1839 and became extinct in 1905. Interestingly, it was the last living species of the Pleistocene wolf lineage and may be the closest relative to the living domestic dog. In the Japanese archipelago, there were two wolf species that were alive concurrently: the Hokkaido wolf (Canis lupus hattai), and the Japanese wolf. The Hokkaido wolf became extinct earlier than the Japanese wolf in 1889. There are now no wolf species living in Japan.
During the Japanese wolf’s prime years, it lived on multiple Japanese islands including Kyushu, Shikoku, and Honshu. The wolf held cultural significance and was highly respected, however, multiple viruses are suspected to be a major cause of the Japanese wolf’s extinction. The wolf was regarded as a protector of the mountains and is the subject of many shrines, especially in mountain towns. Unfortunately, rabies and canine distemper spread rampantly following the virus’ initial introduction to the islands. This had detrimental effects on Japanese wolf populations. Political turmoil at the time was also a significant contributing factor to the wolf’s extinction. The restoration of imperial rule in Japan included the destruction of many culturally significant buildings, the illegalization of particular spiritual practices and rituals, and the persecution of some culturally significant animal species, including the Japanese wolf.
The Japanese wolf was relatively small in comparison to other wolf subspecies and was smaller than the other wolf then alive in Japan, the Hokkaido wolf. The wolf’s shoulder height was at most 23 inches, which to compare, is over half a foot less than modern gray wolves. Current speculation predicts that the Japanese wolf had a primarily gray fur coat, however there is no complete consensus on their appearance. Illustrations of the Japanese wolf are scarce and inconclusive, and only 4 mounted specimens exist today.
3. The Cave Wolf (Canis lupus spelaeus)
The final cool extinct wolf species we will investigate is the cave wolf (Canis lupus spelaeus). The taxonomic name for the cave wolf is fitting because its subspecies name, spelaeus, comes from a latin word meaning cave or cavern. This name is similar to the now extinct cave lion (Panthera spelaea).
The cave wolf was alive between 129,000 and 8,200 years ago. It became extinct during the same period most Pleistocene megafauna also became extinct, the Quaternary extinction event. Many European predators became extinct during this period due to the disappearance of different megafauna prey species and climatic change. A major factor was also the extreme cold associated with this global shift. Cave wolves could shelter themselves in the deepest branches of different cave systems but over time they could still not escape the cold. When they became extinct, a smaller wolf-like species arose. This species later gave rise to the modern European wolf as the Earth warmed again.
The cave wolf was even larger than the modern European gray wolf! It had a shoulder height of approximately 36 inches, half a foot taller than its modern relative. Proportionally, it was quite similar to the Canadian Arctic timber wolf. It is thought to have a mostly tannish-brown coat color with darker markings on its head and tail. The cave wolf had large canine teeth, characteristic of all canid species. These teeth were important to maintaining a carnivorous diet and for aggressive or defensive encounters. Some wolf fossils found near bear fossils show signs of injury. This suggests there may have been aggressive confrontations between these competing predators. There is also ample evidence that suggests the wolves scavenged for bear remains in caves, as well as for vulnerable hibernating bears.
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