Types of Grizzly Bears

In News Article by Matt Shetzer

Grizzly Bear Sow Protecting Her Cub

Grizzly Bear Sow and Cub from Alaska

The scientific name for most types of grizzly bears is “ursus arctos horribilis.” Horribilis. Even the scientific community is scared of grizzly bears.

“Grizzly Bears” are often thought of as vicious, top-of-the-food-chain predators who will stop at nothing to harm you. The reality is that the term “grizzly bear” encompasses several different types of grizzly bears, all of which exhibit different behaviors, and none of which are really that horrible to humans. Only three humans have been killed by grizzly bears this year. Humans are much more dangerous to grizzlies than grizzlies are to humans— humans have hunted two types of grizzly bears to extinction within the last century.

Grizzly bears are brown bears. Many people do not know that grizzly bears are officially defined as any North American sub-species of brown bears. What would qualify as a brown bear in Siberia would likely be classified as a grizzly bear if it was sighted on this side of the Bering Strait.  However, due to geographic and evolutionary factors, there are several distinct types of grizzly bears in North America.  Most people cannot differentiate between the various types of grizzly bears, and indeed, there is debate within the scientific community over the number of subspecies present within North American grizzly bear populations.    The earliest classification system suggested that there could be as many as 90 subspecies of brown bears. However, modern DNA analysis has revealed that most grizzly bears are quite genetically similar. There are two main subspecies of grizzly bears alive today: The mainland grizzly bear, and the larger Kodiak bear. The two species have been evolutionarily distinct since the last ice age.

Large Grizzly Bear Fishing

A large male grizzly walks to the beach to enjoy its catch of salmon

Mainland Grizzly Bear- ursus arctos horribilis.  Mainland grizzly bears account for the vast majority of the various types of grizzly bears. These bears are any of the silver-tipped grizzlies found in Alaska and the Greater Yellowstone ecosystem. These bears will reach weights between 400 (full-grown female) and 800 pounds (full-grown male).

Kodiak Bear- ursus arctos middendorffi.  Kodiak bears are the largest possible subspecies of grizzly bear, due to the easy availability of salmon and other high-protein food sources in their habitats on the Kodiak Archipelago in Southwestern Alaska. Kodiak Bears can reach weights up to 1,500 pounds, and heights up to ten feet. Kodiak bears became an evolutionarily distinct group 12,000 years ago, when an ice age separated their habitat from the Alaskan mainland.

Peninsular grizzly Bear- ursos arctos gyas. The peninsular grizzly bear is a disputed subspecies; many biologists believe that they should be classified as ursus arctos horribilis, and not a separate subspecies.

California Grizzly Bear- ursos arctos californicus (extinct). Despite gracing the state flag, California Grizzly Bears have been extinct since 1922. This type of grizzly bear was hunted into extinction.

Mexican Grizzly Bear- ursos arctos nelsoni (extinct).  Mexican grizzly bears are also presumed extinct. The Mexican Grizzly Bear is the smallest known grizzly bear species. The bear was known as “el oso plateado” (the silver bear) due to its distinctive grayish/silver coloring. This type of grizzy bear was trapped and hunted into extinction by the mid-1960s.

Grizzly Bear Fishing in Habitat

A grizzly enjoying fishing in an Alaskan river

Grizzly Bear/Polar Bear Hybrid.  In very rare circumstances, polar bears and grizzly bears can cross-breed. This most often occurs when zoos keep the animals in the same enclosure. A pair of polar bear/ grizzly bear cubs were born at Osnabrück Zoo in Osnabrück, Germany in 2004, after 24 years of cohabitation between a polar bear and a grizzly bear.  The grizzly bear/ polar bear hybrid has no scientific name, but it is sometimes colloquially referred to as a “grolar bear” or “prizzly bear.” These hybrid bears are larger than an average grizzly, but smaller than an average polar bear.  As of 2009, there were 17 of these hybrid bears living in captivity, mostly in Eastern European zoos. This type of grizzly bear has only ever been observed twice in the wild; hunters killed both bears sighted in the wild. Scientists have conducted DNA sequencing on the hunted animals to determine the exact heritage of the hybrid bears.


Types of Grizzly Bears was last modified: December 4th, 2017 by Matt Shetzer