In this blog, I want to contrast two species of deer; the White-tailed Deer (Odocoileus virginianus) and the Mule Deer (Odocoileus hermionus). For me, the White-tailed Deer is a symbol of home; this species is extremely common throughout Ohio and I have had many experiences observing individuals in the wild. The Mule Deer, on the other hand, is a symbol of less familiar, more adventurous western states. I have spent this month in Montana, and observing both species has me contemplating their similarities and differences, as well as how they interact in areas of sympatry (inhabiting the same geographic region). In this blog I will attempt to answer the following questions: What physical differences exist between White-tailed and Mule Deer? What behavioral differences exist between White-tailed and Mule Deer? How much competition is there between White-tailed and Mule Deer in areas of sympatry?
Mule Deer are slightly larger than White-tailed Deer on average. The most notable differences between the species involve the ears, antlers, and tail.
White-tailed and Mule Deer have similar general habits such as a small home range, polygynous breeding system (one male mates with multiple females), and crepuscularity (being most active at dawn and dusk). However, notable differences are seen in group size and composition and behavior in the presence of a predator. Habitat differences will be discussed later. Mule Deer typically form larger, more stable groups than White-tailed Deer. In winter, Mule Deer frequently form groups consisting of both sexes, while White-tailed Deer more often form female groups of related individuals (mother and fawns). Mule Deer groups might be more stable due to stronger associations between individuals (time spent together), which has been observed between fawns. When a predator is observed, White-tailed Deer flick their tail back and forth, and if the danger is perceived as great enough, will run to cover in long leaps with their tails straight up. Mule Deer will often hop, lifting all four limbs at once, and after a distance will stop and turn to observe the predator. This species does not raise its tail, which in White-tailed Deer is a warning to other individuals.
The White-tailed Deer inhabits most of the continental US, while the Mule Deer's range is more to the west and extending farther north into Canada. The ranges overlap in many areas of the west (see maps below). When two or more species that fill the same ecological niche, referring to place in an ecosystem in terms of diet, habitat, etc., inhabit the same geographic region (sympatry), Both species have similar diets, so when both species inhabit an area they likely compete for food, particularly in harsher winters. However, one paper suggested that predation helps prevent competition between the two species. Both species can survive in a variety of habitats, but White-tailed Deer tend to prefer lower areas and forest interiors and edges, while Mule Deer prefer higher and more open areas (although there are four subspecies that live in very different habitats). When confronted by coyotes, Mule Deer tend to run to higher and more rugged terrain, while White-tailed Deer run towards lower, more gentle terrain.
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Another interesting occurrence in areas of sympatry is hybridization between Mule and White-tailed Deer. Hybrids have been recorded in British Columbia, Alberta, and Texas, as well as other locations. At least some of the hybrids have been fertile.
As an endnote, both White-tailed and Mule Deer are members of the family Cervidae, in the order Artiodactyla. This family has the defining characteristic of antlers, which are shed annually (other Artiodactyls such as the Pronghorn (Antilocapra americana) have horns, which are never shed). Other Cervids include Elk (Cervus canadensis), Moose (Alces alces), and Caribou (Rangifer tarandus). White-tailed and Mule Deer are relatively common species that can often be seen (depending on your location) through minimal effort. You can observe them on a drive to work, or a quiet walk through a park. Whether you are a photography enthusiast, hunter, regular park visitor, or otherwise, you can admire the beauty and graceful movements of these Cervids.
Mule Deer are slightly larger than White-tailed Deer on average. The most notable differences between the species involve the ears, antlers, and tail.
- Mule Deer have very large ears in comparison to the head (this is the origin of the species' name).
Mule Deer (my picture)
White-tailed Deer (my picture)
- The Mule Deer's antlers fork out multiple times, while the White-tailed Deer's antlers have one main shaft with multiple points (tines).
Mule Deer buck (picture from Google Images)
Mule Deer buck side view (picture from Google Images)
White-tailed Deer (picture from Google Images)
White-tailed Deer Buck side view (Picture from Google Images)
- Lastly, the Mule Deer's tail is narrower and with a black tip, while the White-tailed Deer's tail is thicker and all white (hence it's name) (see image below).
Mule Deer doe (Picture from Google Images)
White-tailed Deer doe (Picture from Google Images)
White-tailed and Mule Deer have similar general habits such as a small home range, polygynous breeding system (one male mates with multiple females), and crepuscularity (being most active at dawn and dusk). However, notable differences are seen in group size and composition and behavior in the presence of a predator. Habitat differences will be discussed later. Mule Deer typically form larger, more stable groups than White-tailed Deer. In winter, Mule Deer frequently form groups consisting of both sexes, while White-tailed Deer more often form female groups of related individuals (mother and fawns). Mule Deer groups might be more stable due to stronger associations between individuals (time spent together), which has been observed between fawns. When a predator is observed, White-tailed Deer flick their tail back and forth, and if the danger is perceived as great enough, will run to cover in long leaps with their tails straight up. Mule Deer will often hop, lifting all four limbs at once, and after a distance will stop and turn to observe the predator. This species does not raise its tail, which in White-tailed Deer is a warning to other individuals.
Portion of a herd of Mule Deer in southeast Montana (my picture).
Mother and fawns that visited my yard throughout my senior year of college (my picture).
Mule Deer hopping (Image from Google Images).
White-tailed Deer running, with its tail straight up in alarm (Image from Google Images).
The White-tailed Deer inhabits most of the continental US, while the Mule Deer's range is more to the west and extending farther north into Canada. The ranges overlap in many areas of the west (see maps below). When two or more species that fill the same ecological niche, referring to place in an ecosystem in terms of diet, habitat, etc., inhabit the same geographic region (sympatry), Both species have similar diets, so when both species inhabit an area they likely compete for food, particularly in harsher winters. However, one paper suggested that predation helps prevent competition between the two species. Both species can survive in a variety of habitats, but White-tailed Deer tend to prefer lower areas and forest interiors and edges, while Mule Deer prefer higher and more open areas (although there are four subspecies that live in very different habitats). When confronted by coyotes, Mule Deer tend to run to higher and more rugged terrain, while White-tailed Deer run towards lower, more gentle terrain.
Mule Deer Range Map
White-tailed Deer Range Map
Another interesting occurrence in areas of sympatry is hybridization between Mule and White-tailed Deer. Hybrids have been recorded in British Columbia, Alberta, and Texas, as well as other locations. At least some of the hybrids have been fertile.
As an endnote, both White-tailed and Mule Deer are members of the family Cervidae, in the order Artiodactyla. This family has the defining characteristic of antlers, which are shed annually (other Artiodactyls such as the Pronghorn (Antilocapra americana) have horns, which are never shed). Other Cervids include Elk (Cervus canadensis), Moose (Alces alces), and Caribou (Rangifer tarandus). White-tailed and Mule Deer are relatively common species that can often be seen (depending on your location) through minimal effort. You can observe them on a drive to work, or a quiet walk through a park. Whether you are a photography enthusiast, hunter, regular park visitor, or otherwise, you can admire the beauty and graceful movements of these Cervids.
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