The Largest Wolf in History was Twice the Size of a Dire Wolf

Dire wolves, brought back into the spotlight through recent cloning efforts, are often portrayed as the greatest of prehistoric canines. Yet, even the largest dire wolf would pale in comparison to Epicyon haydeni. This colossal canine, whose very name translates to “more than a dog”, truly lived up to its epic monker, reigning as the largest wolf to ever walk the Earth.

A Canine Titan Even Bigger Than a Dire Wolf

Epicyon haydeni, or Hayden’s bone-crushing dog, roamed North America between 12 and 6 million years ago during the middle to late Miocene epoch. Its fossils have been discovered in at least 12 different states across the United States.

Epicyon was the largest member of the canine family to ever live. These gigantic wolves were 8 feet long, stood nearly 3 feet tall at the shoulder, and weighed between 220 and 276 pounds. But so far, the largest ever found weighed in at an astounding 370 pounds! To put that size into perspective, these wolves grew roughly the size of a large grizzly bear or an African lion. In contrast, dire wolves were half that size, measuring 6 feet long and weighing around 150 pounds, although some could reach 200 pounds or more.

Epicyon’s Bone-Crushing Lifestyle

Epicyon haydeni was the largest of all the Epicyon species. Like other meat-eating animals, these colossal wolves had special “carnassial” teeth for slicing meat. Their molar teeth further back were much larger and strong enough to crack open bones. Fossils show that these back teeth were often heavily worn down, suggesting that they regularly chewed and crushed bones.

Epicyon belonged to a group of extinct canines called borophagines. Known as bone-crushing dogs, borophagines had thick skulls and powerful jaws. Epicyon haydeni were likely both hunters and scavengers, similar to modern hyenas. They hunted several animals that are now extinct, including ancient pronghorn, camels, horses, and even rhinoceroses. Their specialized back teeth allowed them to easily crush bones and access the nutritious bone marrow inside.

With their incredible size and impressive power, Epicyon haydeni were a force to be reckoned with. However, they weren’t the only large predators around. These massive wolves had to compete with large carnivores like sabertooth cats, bears, and other bone-crushing dogs. However, they worked together and hunted in groups, much like modern wolf packs. While they weren’t built for long-distance running due to their size, they could move quickly in short bursts. Their skulls also had a flattened front and shorter snout like a lion or hyena. This gave the wolves more power and strength for scavenging and crushing open bones, a major advantage over other carnivores.

The Extinction of the World’s Largest Wolves

Even though Epicyon haydeni was a strong and powerful predator, things began to shift around 18.5 million years ago as big cats migrated to North America. The giant wolves now had new competitors for food and other resources — ones that could hunt alone with their retractable claws, flexible bodies, and sharp, meat-slicing teeth.

Around the same time, the environment and climate were rapidly changing. Forests were shrinking, and grasslands were expanding. This new open landscape favored fast hunters who could chase prey across longer distances. Unfortunately, this was a problem for animals like Epicyon haydeni. These wolves were built for ambushing and overpowering prey with their strength, not speed. The cats and other types of wolves, however, were perfectly suited to the new environment and quickly became top predators. As a result, by the late Pliocene epoch, the last of the bone-crushing dogs, including Epicyon haydeni, went extinct.