Every living thing on Earth that is known to science is biologically classified into seven hierarchies. The classification begins with whether the organism is animal, plant, fungus or bacteria, and each step down the information ladder helps define what a species is. The system can help establish close relationships between species based on shared characteristics, and more recently, based on genetic similarities.
As multicellular organisms that rely on other organisms for food, deer are members of the animalia kingdom. Deer share this kingdom with an estimated 9 to 10 million other species. Members of this kingdom are capable of movement, unlike plants or fungi.
The next step down from kingdom is the phylum, which is a grouping based on specific anatomical features. The phylum for deer is chordata. Chordata members all have a notochord as embryos, which in some species develops into a spine.
The next step in establishing a species is the class, which are groups such as mammals, reptiles, fish and birds. Deer are members of the mammal class, along with about 5,000 other animal species. An animal is classed as a mammal if it has hair, middle ear bones and if females produce milk for their young.
Next, mammals are split into orders. Deer are in the artiodactyla order with about 220 other species. Members of this order are recognized by symmetry in the feet. Most of the animals in this category have feet in which the third and fourth toes are the weight-bearing digits.
Deer species are next broken down into a suborder known as ruminantia. Members of this group are characterized as having multichambered stomachs, no upper incisor teeth, a slender body shape and often some form of horns or antlers. Other members of ruminantia include sheep, goats and cows.
Deer belong to the cervidae family, which is made up of 44 species. Members of this family are varied in size and appearance but all have slender legs. Almost all of the 44 species have antlers or horns made of bone. Other members of cervidae include moose and elk.
Subfamily and Genus
The cervidae family has three subfamilies: capreolinae, cervinae and hydropotinae. These subfamilies are further divided into dozens of genus groups in which one or more deer species are classified. Each deer species' genus is determined by distinctive characteristics of the animal and common traits shared with other species.