A black sheep is a rare color morph of the domesticated sheep (Ovis aries). As the dominant gene for coloration in sheep is one which shuts color off, most sheep are white. However, if two parent sheep are heterozygous for the black coloration gene, meaning they possess both dominant and recessive black genes, a black lamb will result about 25% of the time.
Scientific & Common Names
Kingdom – Animalia
Phylum – Chordata
Class – Mammalia
Order – Artiodactyla
Family – Bovidae
Subfamily – Caprinae
Genus – Ovis
Species – O. aries
Common Names – Black Sheep
Black sheep look just like their white counterparts, with a fairly small, stocky body and tightly curled and crimped wool. However, their skin and wool are entirely black. As ruminants, their stomach is many chambered to ferment food before it is digested, and as bovids in the order Artiodactyla, they are even-toed hoofed mammals.
Black sheep are not selectively bred, as their wool is considered less valuable than that of white sheep. They occur in about a quarter of births where both parents are heterozygous, containing both dominant and recessive gene variants for black coloration. However, this does not mean that 25% of sheep are born black. Since most white sheep do not possess the heterozygous configuration for black color, black sheep are quite rare.
Black sheep stand out quite vividly amongst a flock that is all white. Thus, the term “black sheep” has grown to become a term that describes someone who goes against a group. However, actual black sheep engage in the same social behavior as the rest of the flock, and sheep do not discriminate against each other due to their coloration.
The phrase “black sheep” is associated with anyone who is an “outsider” amongst a particular group, especially a family. Nearly 20 languages including German, French, Spanish, and English use the phrase in this particular way. The black sheep is the subject of a popular nursery rhyme, “Baa Baa Black Sheep”, which was written over 250 years ago and hasn’t changed much in all that time. There is no clear evidence for the origin or meaning behind the rhyme, although some believe it has to do with a tax on wool.
While there are over a billion domestic sheep in the world, black sheep are far less common due to the unlikely circumstances that result in their birth. However, as they are not a separate species or subspecies of O. aries, but rather a rare color morph, there is no separation of white and black sheep for the purposes of determining conservation statistics.