This seems like an odd question, but when you think about it, it makes sense. Dogs and bears look similar, are they more related in their evolutionary history than the average person knows? Well, thankfully, science has some great answers to the history and taxonomy of many animal species on Earth. Bears do look a bit like a big, thick dog, don’t they? Well, let’s be sure: are bears related to dogs?
The main issue here is one of evolutionary history. When we ask if something is “related,” we are asking whether two animal species have close relatives to each other. Quick answer to this question: Bears are not directly related to dogs. However, they do have an ancient ancestor shared between the two species. As a second note of equal importance, if not more, each creature is related. Humans share a common genetic ancestor with jellyfish and fungi, but these relationships are much more distant than our relationship with chimpanzees. The real question (and probably a more helpful one) is how closely and distantly (in time) the species are related. You will soon discover that the common ancestor of dogs and bears lived 62-32 million years ago. Although both animals are mammals, they are separated from this common ancestor today. Let’s dive into more details of this relationship!
How do we know if something is relevant?
All questions about whether one species is “related” to another depend on evolutionary history. Essentially, what one is asking is, “How far back did these two species have a common ancestor.” Evolutionary research allows us to look back in time (through several different methods) and piece the puzzle together, giving us a more complete picture of the genetic heritage shared by all living things. If you go back far enough, all living things have an ancestor.
Humans have several ways to study the interconnectedness of different species. The most popular (from a public perspective) is probably the fossil evidence. We can often unearth bone or fossil impressions that clearly show themselves as some quasi-species from which two current (extant) species may have originated. The most recent link between two species is called a common ancestor. The second and more important way we can look at shared evolutionary history is through DNA. DNA evidence allows us to look back with relative certainty to see how closely things were related. When two species share extremely similar DNA, they are likely to be closely related and have a not-so-distant common ancestor.
What are taxonomic classifications?
While boring, it’s important to understand how scientists classify organisms. We can’t know if something is relevant without knowing the classification! This is a basic overview of classification. In order to understand “relatedness” on an evolutionary scale, it is important to understand the grouping system that humans use to understand things. Think of the taxonomy as a pyramid, with the most general and comprehensive definitions at the top and the most specific and detailed definitions near the bottom. For example, the six kingdoms (the second largest category) include plants, fungi, animals, etc. The most specific classification, species, includes closely related things such as polar bears, grizzly bears, and black bears.
Now, to solve the immediate problem, how closely related are dogs and bears? We previously determined that, while they are not directly related, there are some classifications that reveal the closeness of the relationship. However, the truth is that these two animals are relatively closely related! Both dogs and bears belong to the suborder Caniformes (literally, dog-like carnivores. Many species in this order (the most recognized animals) the specific way) all have claws that cannot be retracted and are generally omnivorous. This suborder split off from Felis (cat-like carnivores) from which lions, cats, and other felines evolved. Within the Canis suborder, nine families currently exist. Dogs and wolves belong to the Canidae family, while bears belong to the Ursidae family.
What is the most recent common ancestor between bears and dogs?
Now that we understand some of the basics of evolutionary relatedness, let’s take a look at the latest common ancestor shared by bears and dogs! Remember that this ancestor was the forerunner of bears and wolves/dogs and some other families. Miacids are extinct, living 62-32 million years ago. They were quite successful, surviving at least 28 million years. These extinct mammals are thought to have evolved into the modern basis of Carnivore, in which the Canines and Felis suborders diverged. They may look like minks and weasels, some living in trees and others on the ground.
