The jaw analysis of an ancient bone crusher has shown that these creatures were actually omnivores, contrary to the belief that they purely live off of meat.
The canid belonging to the Borophaginae lived in North America between 10 million and 30 million years ago and is believed to succumb to extinction because of their failure to compete with the ancestors of modern coyotes, wolves and foxes.
The Ancient Bone Crusher
Scientists initially believed that Cynarctus wangi has a diet the consisted entirely of meat because of its powerful jaw, but further analysis showed that the bone crusher may have behaved like modern hyenas.
About two-thirds of the animal's diet consisted of insects and plants, similar to a mini-bear's diet, said Steven Jasinski of the University of Pennsylvania.
The Modern Day Dog
There are conflicting studies about this argument, all pertaining to the anatomy, behavior and diet of dogs.
One study claims that dogs are not 100 percent carnivores because their molars have flat surfaces designed to crush bones and grind fibrous plants. While another literature contends that modern day dogs do not have flat molar surfaces; in fact, their huge and sharp teeth are designed as such for shredding, ripping, shearing and grabbing meat.
Modern day dogs evolved from carnivorous wolves some 15,000 years ago and that alone makes them more inclined to become carnivores. Their genetic make-up formed their teeth, their jaws, their gastrointestinal systems and even their behavior.
Dogs also have omnivore qualities, however. They have the ability to digest almost 100 percent of the carbohydrates in their diet. Modern genetics have proven that dogs have genes that are vital for fat metabolism and starch digestion even if their external anatomy is specialized for meat consumption.
To set the record straight, dogs do not grind their food - they chop it. Dogs also do not have any amylase in their saliva. Amylase is a salivary enzyme that helps digest the carbohydrates to become simple sugars before it goes inside the stomach. Dogs produce amylase in the pancreas and small intestines, allowing them to still digest carbohydrates.
Dogs have big stomachs that has high concentration of acids to help breakdown much of the animal protein in their diet. Based on history, dogs were able to survive on non-meat leftovers of humans, so modern day dogs can survive by having vegetables in their diet.
President of Maybeck Animal Hospital and veterinarian Roger Welton, who believes that dogs are omnivores, said that dogs should have a dietary intake of healthy vegetables like broccoli, carrots, green beans, celery and spinach.
"It is also a good idea to integrate complex carbohydrate sources, such as brown rice and sweet potato, as well as some canine safe fruits like cantaloupe, apples and pears," Welton wrote in his blog.
Photo: Bureau of Land Management | Flickr