Deer vs. Reindeer
The main difference between Deer and Reindeer is that Deer have adaptations for moderate climate ecosystem and only males of deer species grow antlers whereas, Reindeers have adaptations for cold climate, and both male and female of reindeer grow antlers.

Key Differences
Deers are adapted to moderate climate whereas reindeers are adapted to cold climate.
Deers have almost 90 species on the other hand reindeer have 10 subspecies.
Deers have long, slim legs with pointed hooves conversely reindeer have long, stumpy legs with wide, split hooves.
Only male deers grow antlers while both sexes of reindeers grow antlers.
Deers live in savannas, meadows and various type of forests on the flip side reindeers live in the tundra and boreal forests.
Deers are distributed all over the world except Antarctica, and Australia wheres reindeer are present in the Arctic, Subarctic regions, Northern Europe, Siberia, and North America.
Deer is small to medium size animal while reindeer is medium to the large size of deer.
Deer consumes leaves, grass, fruit, lichens, and twigs while reindeer usually eat willow leaves, moss, lichens, birch, mushroom and also small rodents, eggs and fish during food scarcity.
Deers have less dense fur while reindeer have more dense fur.
The predators of deer are bears, wolves, cougars, vultures, and humans while the predators of reindeer are beers and humans.
The fur color of deer varies according to the species whereas fur color of reindeer varies according to habitat.
Deers have long, pointed, forked antlers whereas reindeers have large antlers as compared to their body size with upper and lower points organized into separate groups.
Comparison Chart
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A deer is a hoofed, browsing animal with bony, branched antlers carried by males.
A reindeer is a large type of deer with large antlers carried by both males and females.
Habitat
Meadows, savannas, forests
Tundra, boreal forests
Climate Adaptation
Moderate climate
Cold climate
Hooves
Pointed hooves
Wide, split hooves
Size
Small to large size
20 to 1000 pounds
Medium to small size
180 to 400 pounds
Fur
Less fur density
High fur Density
Legs
Long, thin legs
Long, stumpy legs
Color of Fur
Reddish brown to greyish brown
Dark brown to white
Antlers
In males
In males, females
Deer and Reindeer Definitions
Deer
Any of various hoofed ruminant mammals of the family Cervidae, characteristically having deciduous antlers borne chiefly by the males. The deer family includes the white-tailed deer, elk, moose, and caribou.
Reindeer
A large deer (Rangifer tarandus) of the Arctic tundra and northern boreal forests, having large hooves and long branched antlers, and widely domesticated in Eurasia. Subspecies native to North America and Greenland are usually called caribou.
Deer
A ruminant mammal with antlers and hooves of the family Cervidae, or one of several similar animals from related families of the order Artiodactyla.
Reindeer
(plural: reindeer) Any Arctic and subarctic-dwelling deer of the species Rangifer tarandus, with a number of subspecies.
Deer
(in particular) One of the smaller animals of this family, distinguished from a moose or elk
I wrecked my car after a deer ran across the road.
Reindeer
Any species, subspecies, ecotype, or other scientific grouping of such animals.
Deer
The meat of such an animal; venison.
Oh, I've never had deer before.
Reindeer
To herd or farm reindeer
Deer
Any animal, especially a quadrupedal mammal as opposed to a bird, fish, etc.
Reindeer
Any ruminant of the genus Rangifer, of the Deer family, found in the colder parts of both the Eastern and Western hemispheres, and having long irregularly branched antlers, with the brow tines palmate.
Deer
Any animal; especially, a wild animal.
Mice and rats, and such small deer.
The camel, that great deer.
Reindeer
Arctic deer with large antlers in both sexes; called reindeer in Eurasia and caribou in North America
Deer
A ruminant of the genus Cervus, of many species, and of related genera of the family Cervidæ. The males, and in some species the females, have solid antlers, often much branched, which are shed annually. Their flesh, for which they are hunted, is called venison.
Deer
Distinguished from Bovidae by the male's having solid deciduous antlers
Deer vs. Reindeer
The deer is a term that indicates a family, whereas reindeer is a particular specie. Deer is an habitant of savannas, meadows, mixed forests while reindeer is an habitant of tundra and boreal forests. Deers have distribution all over the world, excluding Australia and Antarctica whereas reindeers are present in the Arctic, Subarctic regions, Northern Europe, Siberia, and North America. Deers have adaptations towards moderate climate and reindeer have adaptations towards the cold climate. Deers are large to small-sized animals; The smallest species of deer is Pudu that weighs 20 pounds, while the largest species of deer is Moose that have 1000 pounds of weight while reindeer is medium to large-sized deer that have 180 to 401 pounds of weight. The only male of deer species grow antlers, but both of the sexes of reindeer grow antlers. Deer have long, sharp and forked antlers while reindeer have larger antlers as compared to their body size with upper and lower points organized in two separate groups. Deer have about 60 extant species whereas reindeer have almost ten subspecies. Deer have long, slim legs whereas reindeer have stumpy legs. Deer have less thick fur with the same color in all geographic locations while reindeer have denser fur whose color depends on geographic locations.
What is Deer?
A deer is a member of the Cervidae family that is a hoofed, grazing animal with bony, branched antlers. It is a medium-sized animal that has almost 90 different species of mammals. Their distribution is on all continents excluding Australia and Antarctica. They survive in forests, savannas, riverbed lands, and meadows. The most common species of deer is whitetail. Buck is the male deer while the dose is a female. The smallest species of deer is pudu that weighs 20 pounds, and the largest type of deer is moose that have 1000 pounds of weight. As they are ruminants, their stomach is four-chambered that digest and absorb the nutrients better. Only males have antlers that are long, forked, and pointed. The buck sheds off the velvet on its antlers yearly. The legs of deer are long and thin with pointed hooves. Deer have less dense fur, and its color is the same in all geographic location. The reproduction rate of deers is high. Humans benefit from deer in many ways, including game, meat hunting, traditional medicine, farming, and horns.
What is Reindeer?
Reindeer is a large type of deer with large horns, also known as caribou. Reindeer have about 10 subspecies that lives in the Arctic, Subarctic regions, Northern Europe, Siberia, and North America. Reindeer inhabits boreal forests and tundra. The weight of reindeer is 180 to 401 pounds. Both sexes of reindeer have antlers, and they are larger as compared to their body size with velvety fur covering. They also shed the velvet of antlers yearly. Their nasal cavity consists of special turbinal bones that warm the cold air during inhaling. They have split, wide hooves that help them move easily across the snow. Their long, stumpy legs click whenever they stop and is audible far away.
The color of fur varies according to the geographical area. Arctic region population has whiter fur, and Southern populations are darker comparatively. They can benefit humans by assisting in transportation, providing a source of milk, fur, meat on the farms. Reindeer eat lichens, moss, leaves of willow, birch, mushroom, small rodents, eggs, and fish.