Amphicyon

Name Meaning:  Ambiguous dog

Geologic Era: Early Miocene

Location Discovered:  North America

Size:  2.5 meters long

Estimated Range:  North America, Europe, Asia, Africa

Extinction Date:  16 million years ago

Measuring up to 2.5 meters long and around 1.5 meters tall at the shoulder, Amphicyon looked very much like a cross between a bear and a dog.  It is actually not closely related to either, though it did coexist with the ancestors of modern canids, felids, and ursids.  The cast below nicely illustrates the canid style dentition, with a more bear-like robustness and strength.  The incisors and one premolar are missing (as they must have been in the original specimen), though the remaining teeth are quite impressive.

Amphicyon had a near-worldwide range, with this particular species being from North America.  A look at the complete skeleton reveals an animal that was not built for speed, but rather for power.  Amphicyon was not a predator that was able to endure long-distance chases.  So, it was probably an ambush predator, striking from dense plant growth and perhaps chasing prey a very short distance.  The forearms of Amphicyon are also very robust and strong, so it is possible that its attack strategy involved wrestling prey to the ground. 

The overall impression is an animal that is well suited to taking down large, slow prey, but very ill-suited to smaller, swifter prey.  On the menu were probably larger animals such as Chalicotheres, relatives to modern horses.  Like most carnivores, Amphicyon may have occasionally scavenged as well.  Its heavy jaws and teeth (with attending muscles) would have been more than able to crunch through most bones.  In fact, one of the nicknames for this group of animals is “bone-crushing bear dog.”

There is little to no evidence that Amphicyon was a pack hunter like modern wolves and wild dogs.  It probably behaved more like a bear, with solitary habits generally avoiding others of its kind.  Ultimately, its size and habits eventually worked against Amphicyon with the coming of smaller, faster pack hunters such as wolves.  Prey animals also began to change near the time of Amphicyon’s extinction, trending toward speed as opposed to size and strength.  Amphicyon would have had great difficulty chasing down faster moving prey, and would have been out-competed by newer predators such as true canids and felines. 

An interesting side note is that Amphicyon (or an animal very much like it) in modern mythology.  In Native American legend, an animal they called the Waheela was frequently reported in the Northwest Territory in Canada.  Most Native American accounts describe this animal as being an overly large, almost bear-like wolf.  Adding to this legend is the particular valley these animals have been sighted in, Nahanni Valley, is also known as “Headless Valley” after several gold prospectors were found minus their heads.  Sightings continue sporadically to this day. 

Nahanni Valley is very remote, so the possibility of a large animal living undetected is not as far-fetched as one might think.  One modern sighting estimated the animal to be 3.5 feet tall at the shoulders, which is several inches taller than the largest modern wolf, but within the size range of several Amphicyon species.  Only time will tell if the Waheela is a modern animal, a holdover Amphicyon, or a hoax.

Image Credits:

Full Skeleton: “Amphicyon ingens” by Ghedoghedo – took the foto on the “American Museum of Natural History” in New York. Licensed under Public Domain via Commons – https://commons.wikimedia.org/wiki/File:Amphicyon_ingens.JPG#/media/File:Amphicyon_ingens.JPG

Reconstruction: http://smithsonianhandbook.wikia.com/wiki/Amphicyon_-_Dinosaurs_and_Prehistoric_Life?file=Amphicyon_%25281%2529.jpg