Dog Discoveries

A Fascinating Relationship Between Dogs and Bears

 

We know of dog breeds with a wolfish appearance or dogs with a foxy expression, but there are also some dog breeds that look like bears, with some even looking like the canine impersonation of teddy bears! In case you’re wondering, these breeds are not the outcome of some love affair going on between Rover and Winnie the Pooh, but we sure can’t ignore their bear-like resemblance. Whether it’s a dog’s long snout or fuzzy coat, turns out there actual may be a scientific reason as to why dogs may look a bit like bears. Read on to discover the relationship between dogs and bears.

Meat Eaters At Heartdog meat eating

At first thought, we may assume dogs and bears must have very little in common. Indeed, dogs belong to the canidae family, whereas bears belong to the ursidae family. This means that they are different species, and as such have many contrasting characteristics and cannot breed.

However, at a closer glance, we discover that they are both under the order of carnivora, which includes lions, tigers, bears, cats and dogs. Carnivorans are basically animals that derive nourishment from a diet that’s mainly or exclusively made of meat regardless whether it’s obtained through predation or scavenging. However, not necessarily all members of the order Carnivora adhere to a strict meat diet (obligate carnivors), some eat fruits too and are known as facultative carnivores.

Since most of these animals are meat eaters by preference, Mother Nature has made sure to equip them with excellent senses,  good running abilities ( yes, grizzly bears can outrun a human!) and sharp meat-eating teeth.

caniformiaSharing a Suborder

At some point, carnivores split into two distinct suborders: cat-like animals and dog-like animals. The carnivores that split into dog-like forms were categorized under the suborder group Caniformia.

The carnivores that split into cat-like forms instead fell under the  suborder group Feliformia.

Bears (with their long snouts and non-retractable claws) therefore ended up being grouped within the caniformia suborder along with dog-like animals. Some members of this group can be seen in the picture on the left.

 

 

A Step Back in Timebear and dogs

Prior to splitting into dog and cat forms, carnivorans derived from members of the Miacidae family (miacids). Miacids were small carnivores, equipped with little bodies and long tails. Some lived on trees (arboreal), while others lived on the ground. Their teeth included carnassial teeth, but their teeth were overall less developed than those seen in modern carnivorans. Miacids are therefore considered the ancestors of cats, dogs and bears.

In particular, according to an article by National Geographic,  a fossil has shown that a small, tree-dwelling mammal going by the name of Dormaalocyon latouri,  has been found to be the ancestor of lions, tigers, bears and dogs. This fossil of a miacid is therefore an ancient common ancestor of dogs and bears. Divergence from miacids into carnivores is estimated to have occurred  in the middle-Eocene around 42 million years ago.

Dormaalocyon is the most primitive known member of the carnivoraforms group. That group is represented by today’s 280-plus species of living carnivorous mammals, the order Carnivora, which includes lions, seals, bears, cats, dogs, and others—all of which count this creature as their ancestor,” says paleontologist Floréal Solé.

Did you know?  Bears and dogs cannot mate. Dogs have 78 chromosomes whereas bears have 74. Even though bears and dogs may share a common ancestor, it’s not as recent as the common ancestor leading  to the bear lineage or to the wolf/dog lineage.

 

References:

  • Lindblad-Toh K, Wade CM, Mikkelsen TS, et al. (December 2005). “Genome sequence, comparative analysis and haplotype structure of the domestic dog”.Nature 438 (7069): 803–19.
  • Solé, F., R. Smith, T. Coillot, E. De Bast, T. Smith. Dental and Tarsal Anatomy of ‘miacis’ Latouri and a Phylogenetic Analysis of the Earliest Carnivoraforms (mammalia, Carnivoramorpha). Journal of Vertebrate Paleontology, 34(1): 1-21; 2014
  • National Geographic, Ancient Arboreal Mammal Discovered at Root of Carnivore Family Tree, retrieved from the web on June 3rd, 2016

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