||This documentation needs attention from an expert in Biology. (May 2013)|
In biology, races are distinct populations within the same species and does not apply to genetic differences but phenotype. Because of this, an animal with parents of two different races will be considered to be the race that the animals resembles most closely.
Domesticated, ecological, and geographic races 
Race as a term is almost exclusively used for domesticated species, which is not to say that wild species don't develop races, but a natural population bottleneck event will quickly turn a race in the wild into a subspecies. The populations can be described as ecological races if they arise from adaptation to different local habitats or geographic races when they are geographically isolated.
Race vs. subspecies 
If the races are sufficiently different or if they have been tested to show little genetic connection regardless of phenotype, two or more groups/races can be identified as subspecies, which is an official biological taxonomical unit subordinate to species. If not, they are denoted as races, which means that a taxonomic rank should not be given to the group, or taxonomists are unsure whether or not a formal rank should be given.
According to Ernst W. Mayr, "a subspecies is a geographic race that is sufficiently different taxonomically to be worthy of a separate name." Therefore, biological races are not taxonomical categories.
See also 
|Wikimedia Commons has media related to: Race (biology)|
|Wikiquote has a collection of quotations related to: Race (biology)|