The family Cervidae, which includes all deer, has males that go by several different names depending on their species, age, and location. The most common and widely recognized terms for a male deer are “buck” and “stag.” However, for some of the largest species within the deer family, the male is instead referred to as a “bull.” The specific terminology is often determined by the animal’s size and geographic region, leading to a sometimes confusing collection of names.
Buck and Stag: Primary Adult Terminology
The term “buck” is the most frequently used name for a mature male deer, especially in North America, applying to common species like the White-tailed deer and Mule deer. A buck denotes a sexually mature male, typically one that has developed its characteristic antlers. These species are considered medium-sized within the deer family, with White-tailed bucks typically weighing between 150 to 300 pounds in adulthood. The term is also applied to males of other smaller deer species, such as the Roe deer.
The term “stag” is generally reserved for larger male deer and is more commonly used in Europe and Asia. The European Red Deer, one of the largest deer species, is consistently referred to as a stag. A stag is defined as a fully grown, mature male that is older, heavier, and has developed a massive rack of antlers. While “stag” and “buck” can sometimes be used interchangeably, a mature Red Deer stag can weigh over 500 pounds.
Names Based on Age and Antler Development
Beyond the general names for a mature animal, male deer are classified by their age and the stage of their annual antler growth cycle. A “fawn” is the term for any young deer during its first year of life, regardless of sex. Fawns are characterized by their spots and are highly dependent on the female, or doe.
A male deer in its second year is often called a “yearling,” which describes its age rather than its antler status. If a yearling male grows a simple, unbranched antler, it is commonly known as a “spike” or “spike buck.” These initial antlers are typically short and straight, resembling simple spikes rather than the complex, branched structures of older males.
Antler development is directly influenced by age, nutrition, and genetics, with a buck’s antlers typically not reaching their maximum size until the animal is between five and seven years old. The growth process begins with a bony structure forming on the skull, from which the first true antlers emerge. The number of points on an antler, while often used to estimate age, is not a definitive measure.
When the Term is “Bull”: Major Species Exceptions
For the largest members of the Cervidae family, the male is referred to as a “bull,” borrowing terminology historically applied to bovine animals like cattle. This term is typically used for species that are significantly larger than White-tailed or Mule deer. The term “bull” is used for the male of the North American Elk, also known as Wapiti, which is the second-largest deer species globally.
The largest species in the family, the Moose (Alces alces), also has a male that is called a bull. Adult bull Moose can weigh over 1,500 pounds and stand over six feet tall at the shoulder. This “bull, cow, and calf” nomenclature is also applied to Caribou, or Reindeer (Rangifer tarandus), the males of which are also called bulls.
Using “bull” for these massive deer species provides a clear distinction from the smaller bucks and stags. The corresponding female for these larger species is called a “cow,” and their young are called “calves.”