An Ultimate Guide to Epicyon: The Above Dog

Leave a comment / / Updated on: 24th September 2023

Name MeaningMore than a dogHeight0.9 meters (2.95 feet)
PronunciationEpp-ih-sigh-onLength2.4 meters (7.9 feet)
EraCenozoic – Miocene PeriodWeight0.10-0.13 metric tons (220.5-275.6 lbs)
ClassificationMammalia, Carnivora & CanidaeLocationNorth America

Epicyon Pictures

Illustration of epicyon in a white background
Illustration of epicyon in a white background | leoraimbault via Wikimedia Commons CC A-SA 4.0

The Epicyon

Gage Beasley Prehistoric's Epicyon Concept
Gage Beasley Prehistoric’s Epicyon Concept

Imagine a dog as large as a horse with hyena-like molars – this is an Epicyon!

Considered the world’s largest known canid species, the Epicyon lived from the Early Miocene until the Late Miocene. 

It was an inhabitant of today’s North America, being more common in the United States.

Although not all Epicyon individuals were so large, some could reach a length of 2.4 meters (7.9 feet) and a weight of 170 kilograms (374.8 pounds). 

Can you imagine that they weighed twice as much as the largest extant canid species, the gray wolf?

Although it resembles other canids in appearance, some Epicyon characteristics are more similar to hyenas than canids, which may serve as examples of convergent evolution.

Epicyon, the 'more than dog' roamed North America
Epicyon, the ‘more than dog’ roamed North America | DinosaursRoar via Fanon Wiki Fandom

If you’re curious about what else makes these canids stand out among others, keep reading! 

You’re about to discover some fascinating details!

You may also learn why dogs and cats sometimes don’t like each other!

Gage Beasley's Prehistoric Shirt Collection
Gage Beasley’s Prehistoric Shirt Collection
Gage Beasley's Prehistoric Plush Collection
Gage Beasley’s Prehistoric Plush Collection

Physical Characteristics

Although the Epicyon had a typical canid body, it was much larger than extant dogs.

It could reach 2.4 meters (7.9 feet) in length and approximately 100–125 kilograms (220.5–275.6 pounds) in weight. 

However, it is estimated that the weight could go up to 170 kilograms (374.8 pounds) at the maximum. 

The height was probably around 90 centimeters (35.4 inches) at the shoulders.

Gage Beasley Prehistoric's Epicyon Size Comparison Chart
Gage Beasley Prehistoric’s Epicyon Size Comparison Chart

Even the gray wolf, considered the largest extant member of the Canidae family, is much smaller than the extinct Epicyon

Adults measure approximately 1.05–1.6 meters (3.5–5.5 feet) long and 80–85 centimeters (31.5–33.5 inches) tall. 

The weight is estimated at approximately 40 kilograms on average (88.2 pounds), although some individuals reached an extraordinary length of 79.5 kilograms (175.3 pounds).

Although the Epicyon was not much taller than the gray wolf, it was undoubtedly much longer and heavier, thus a stronger predator. 

It is believed that the Epicyon is the largest Canidae species ever known.

The Epicyon also had a remarkably powerful jaw adapted for a carnivore or even a hypercarnivore diet, which included crushing bones.

Its lower fourth premolar and its carnassial teeth, meaning the lower first molar and the upper fourth premolar, were enlarged, similar to those of a hyena, although hyenas do not use these molars to crush bones.

Epicyon was the largest canids who have ever lived
Epicyon was the largest canids who have ever lived | image via Survive The Ark

It’s worth mentioning that the three recognized species, E. aelurodontoides, E. haydeni, and E. saevus, may have differed from each other, although scientists haven’t widely studied these differences.

It is believed, however, that the Epicyon haydeni was the largest of the three. 

The height of Epicyon saevus has been estimated at only 56 centimeters (22 inches) at the shoulder, and the weight at 66.5 kilograms (146.6 pounds). 

Another possible difference is the teeth’ form, dental proportions, and skull shape.

The type species is Epicyon haydeni

Based on specimens attributed to it, scientists confirmed that its small clavicle, digitigrade posture, and flexible back make it similar to other canids in terms of physiology. 

Hand drawn illustration of Gray wolf animal
Hand drawn illustration of Gray wolf animal | L Feddes via iStock

It is often compared to the gray wolf, considering that this is the largest extant canid species. 

On the other hand, studies show that the members of the Epicyon genus resembled spotted hyenas (Crocuta crocuta) more than gray wolves in the robustness of their long bones – humerus, ulna, radius, femur, and tibia.

Besides, similar to hyenas, the Epicyon had a rather short rostrum, a widened palate, and a dome-shaped forehead.

Habitat and Distribution

The Epicyon was widely distributed across North America. Here are the localities that revealed fossils associated with the genus:

  • Florida
  • Nebraska
  • Montana
  • Young Brothers Ranch, Kansas
  • New Mexico
  • Coffee Ranch, Texas
  • Colorado
  • Oklahoma
  • Idaho
  • Oregon
  • Arizona
  • California
  • Alberta, Canada

It is believed that the Epicyon preferred living and hunting in open areas, while other borophangines, like the Aelurodon, preferred more forested regions.

During the Miocene, when the Epicyon was alive, the world was going through a period of increased aridity caused by global cooling, which, in turn, affected the ability of the atmosphere to absorb moisture.

During the Miocene, North America featured a dry, non-seasonal mid-continent climate as a result of the appearance of the Sierra Nevada and Cascade Mountain ranges. 

As such, the predominant habitats on the territory were grasslands.

Behavior and Diet

Epicyon, baring its formidable teeth, feasts on another species
Epicyon, baring its formidable teeth, feasts on another species | Apex Predator GX via VS Battles Wiki

Based on its physical characteristics, scientists argue that the Epicyon was not a very good runner, as in not being able to run at high speeds and over long distances. 

At least this is valid for Epicyon haydeni, which was larger. Epicyon saevus may have been a better runner than its larger relative.

Epicyon haydeni, on the other hand, probably relied on bursts of speed, suggesting an ambushing predation technique. 

Additionally, it may have learned various social hunting strategies that aided in catching prey.

As you’ve already guessed, the Epicyon was a capable predator. 

However, scientists do not rule out the possibility that it was, in fact, an omnivore and did not rely only on killing prey. 

Instead, it may have fed on plants and insects as well. 

Illustration of epicyon killing its prey
Illustration of epicyon killing its prey | Theferretman21 via Dinopedia Fandom

This information is carried by the grindstone-like molars.

Nevertheless, not all specialists agree with this theory and argue that the Epicyon was a pure hypercarnivore.

Scientists suspect it was also an opportunistic scavenger

On the other hand, while hunting may have occurred in groups, scavenging likely occurred in solitude.

The enlarged form of its teeth (similar to hyenas) shows that the Epicyon also relied on crushing and eating bones, as well as extracting bone marrow, which is highly nutritious.

Due to this, specialists believe that the digestive tract of the Epicyon also resembles that of a hyena. 

Mandible of epicyon
Mandible of epicyon | image via Wikipedia CC0

Fossilized species belonging to these canids confirm the bone-crushing behavior.

While hunting prey, the Epicyon relied on its canine teeth near the front of the lower and upper jaws.

Life Cycle

Although few studies focus on the reproduction and lifestyle of the Epicyon specifically, we can outline a possible reproductive behavior based on what is known about canids in general.

Before discussing these details, we must mention one important thing that led scientists to suspect that these animals were sexually dimorphic.

Many scientists consider that Epicyon haydeni and Epicyon saevus were, in fact, the same species, except that one was a male and the other a female. 

This would imply that these canids were sexually dimorphic.

Its size and build made epicyon one of the top predators in its ecosystem
Its size and build made epicyon one of the top predators in its ecosystem | Masonthetrex0916 via Dinopedia Fandom

However, other specialists rushed to disapprove of this theory because no other members of the Canidae showed such a prominent sexual dimorphism. 

Extant canid species show only a 5% size difference, while the difference between Epicyon haydeni and Epicyon saevus is between 16 and 23%.

Having set these details aside, let’s outline the possible reproductive behavior of the Epicyon.

Canids are typically monogamous. Many species are spontaneous ovulators and experience pseudo-pregnancies. 

The gestation period lasts approximately 50-65 days, depending on the species. 

The litter size is between one and 16.

Babies are very small and blind when born. 

Restoration of Epicyon
Restoration of Epicyon | Jarrod Amoore via Wikimedia Commons CCA 2.0

As such, they require parental care, which the parents are more than willing to provide. 

If they live in social groups, the babies experience something called alloparental care, which means that other adults in the group care for the young.

Until they are ready to venture out into the open, the babies are kept in a den dug into the ground. 

The parents and other members of the social group bring them food when they’re ready to start eating solid food. 

At first, the food is regurgitated by the adults.

Baby canids take roughly a year to become adults and learn to fend for themselves. 

Some may remain in the same pack, while others gather to form a new one. 

Life reconstruction of epicyon
Life reconstruction of epicyon | Nobu Tamura via Wikimedia Commons CC A-SA 4.0

This depends on the species.

While these details may not be fully valid for the Epicyon, they’re something we can still rely on. 

Remember that the Epicyon is an example of convergent evolution due to its bone-crushing behavior and enlarged teeth, so it may have retained other traits similar to those of hyenas, which may include aspects related to its reproduction and lifestyle.

Evolution and History

The extinction of non-avian dinosaurs approximately 66 million years ago favored the appearance and diversification of carnivorans.

Roughly 50 million years ago, carnivorans split into feliforms and caniforms. 

The earliest identifiable member of the Canidae family appeared 40 million years ago – it is now called Prosperocyon wilsoni

Soon after, the family divided into three subfamilies: Borophaginae, Caninane, and Hesperocyoninae.

Archaeocyon head restoration
Archaeocyon head restoration | Mariomassone via Wikimedia Commons CC A-SA 4.0

The most primitive member of the Borophaginae subfamily, which includes the Epicyon as well, is the Archaeocyon, a small animal. 

Over time, this subfamily diversified, giving rise to other groups that included much larger canids.

The Epicyon is now a member of the Borophagina subtribe, classified under the Borophaginae subfamily and the Borophagini tribe. 

Other members of this group are Paratomarctus, Caprocyon, and Borophagus.

The Epicyon genus was named in 1858 by Joseph Leidy. It was initially classified under the Canis genus but was later confirmed to have been a borophagine group.

The members of the Borophaginae ended up out-hunting the members of the Caninae and Hesperocyoninae, as they were better predators.

Ancient dog tooth from epicyon
Ancient dog tooth from epicyon | NPS Photo via Wikimedia Commons Public Domain

While the Caninae remained small and preyed on smaller animals, the Borophaginae started competing with the Hesperocyoninae, which led to the extinction of the latter, as they lacked the strong jaws and the bone-crushing teeth of the Borophaginae, Epicyon included.

Consequently, Epicyon hayden and other borophagines evolved so large that they could only hunt massive prey; they simply couldn’t catch smaller prey.

In the end, creatures like the Epicyon dominated North America. 

That is, up until the invasion of cats, which were excellent hunters, probably even better than the ferocious borophagines. 

As such, they started competing with borophagines for food, eventually out-hunting them and leaving Caninae untouched, which is why it survived until today.

Epicyon range based upon fossil finds
Epicyon range based upon fossil finds | Noles1984 via Wikimedia Commons Public Domain

Over the years, scientists have named numerous species based on fossil discoveries. 

Today, however, only three are officially recognized. They are thought to have had a different timeline as follows:

  • Epicyon haydeni – 20.6–5.3 million years
  • Epicyon saevus – 16.3–4.9 million years ago
  • Epicyon aelurodontoides – 1.3–4.9 million years ago

Interactions with Other Species

The Epicyon shared its habitat with other canids, including the Carpocyon, Aelurodon, Paratomarctus, Borophagus, and Canis lepophagus.

There may have been a certain degree of competition for food, but scientists assume that these dogs were of different sizes and had specialized adaptations, indicating that each filled a separate ecological niche. 

Even the species within the Epicyon genus may have filled slightly different ecological roles, thus making cohabitation possible.

Miocene map
Miocene map | Clypeasterrr via Wikimedia Commons CC A-SA 4.0

During the Miocene, North America was quite rich in prehistoric creatures, so it would be impossible to indicate which crossed paths with the Epicyon.

Nevertheless, here are some of the most notable creatures worth mentioning:

  • The Agriotherium bear
  • The Barbourofelis feliform
  • The Amphimachairodus machairodont cat
  • The Aepycamelus camel
  • The Cosoryx pronghorn
  • The Neohipparion horse
  • The Nannippus horse
  • The Prosthennops peccary
  • The Teleoceras rhinoceros

It is thought that Epicyon and other carnivorous mammals stole Agriotherium kills. 

The Barbourofelis feliform may have presented competition for the Epicyon.

Camels, pronghorns, horses, and rhinoceroses may have fallen prey to the Epicyon and other carnivores.

Cultural Significance

Skeletal mount of epicyon on display at the Natural History Museum of Los Angeles County
Skeletal mount of epicyon on display at the Natural History Museum of Los Angeles County | Jonathan Chen via Wikimedia Commons CC A-SA 4.0

Since the Epicyon is the largest canid ever known, it’s unsurprising that scientists showed such an interest in the genus and conducted research that now provides significant information about this creature.

The characteristics and adaptations of these large canids aren’t only important to outline our world’s evolutionary history but are also examples of convergent evolution and provide an insight into the wildlife and landscape of Miocene North America.

On the other hand, although the genus is significant in paleontology, the media didn’t show the same interest.

The Epicyon is indeed present in various prehistoric wildlife handbooks, but it’s not a popular character in movies, documentaries, or video games.

Besides a short appearance in Monsters Resurrected and Primal, the Epicyon remains unknown to the public.

As such, considering its uniqueness, we hope that future media productions will feature Epicyon as a character!


The Epicyon was a North American borophagine canid. 

It was widely distributed across the North American continent, and fossil discoveries led to the naming of multiple species, of which only three are recognized today.

These prehistoric animals existed from the Early Miocene until the Late Miocene and shared their habitats with other canids, feliforms, camels, pronghorns, and horses.

This genus is notable primarily for its large size and specialized teeth adapted for a bone-crushing diet. 

The Epicyon is considered the largest known canid, while its teeth may serve as an example of convergent evolution, as they resemble those of hyenas.


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