What colors can rats be? - briefly
Rats exhibit a range of coat colors, including brown, black, gray, white, agouti, and patterned varieties such as hooded or pied. Albino individuals lack pigment, appearing entirely white with red eyes.
What colors can rats be? - in detail
Rats display a wide range of coat colors resulting from genetic variations that affect melanin production, pigment distribution, and hair texture. The most common color categories include:
- Albino – pure white fur with pink eyes, caused by a lack of melanin.
- Black – solid black fur, often accompanied by pink or ruby eyes in recessive black strains.
- Brown – includes several shades such as chocolate, cinnamon, and dark brown, each linked to specific alleles.
- Agouti – a banded hair pattern producing a speckled appearance; typical shades range from light to dark brown.
- Gray – a diluted form of black, resulting in a softer, silvery hue.
- Cream – a light, diluted brown, frequently seen in “cream” or “fawn” varieties.
Pattern variations modify these base colors:
- Hooded – darker coloration restricted to the head, shoulders, and back, with a lighter belly.
- Blaze – a distinct white stripe running from the nose over the forehead to the eyes.
- Spot – one or more white patches on the head, body, or tail.
- Rex – a texture mutation that produces a velvety, short coat while retaining the underlying color.
Genetic inheritance follows Mendelian principles. Dominant alleles, such as the black (B) gene, mask recessive ones like the brown (b) gene. Dilution genes (d) reduce pigment intensity, converting black to gray or brown to cream. The albino condition results from two copies of a recessive allele (aa) that blocks melanin synthesis entirely.
Selective breeding can combine multiple traits, producing complex phenotypes such as a black hooded rat with a blaze or a sable rat exhibiting both agouti and dilution characteristics. Breeders monitor genotype combinations to predict outcomes and avoid undesirable health issues linked to certain color genes.
Overall, rat coat coloration is governed by a limited set of pigment genes interacting with pattern and texture modifiers, yielding the diverse palette observed in domestic and laboratory populations.