One of the volunteers of an animal rescue group is caring for a male calico kitten, a feline so uncommon it is often called a unicorn.
He and his siblings were born in a Weld County shed and were taken to the Weld County Humane Society before coming to NoCo Kitties. Alli Magish, who is fostering the three kittens and their mother, Amber, suspects one of the three calicos might be male, and a veterinarian confirmed that suspicion.
Veterinarians say only one in 3,000 calico kittens is male. In calicos, different color genes are passed down from their parents through the X chromosome. XXY chromosomes can cause calico coloring in male kittens with only one X and one Y chromosome.
A male calico can also result from chimerism, in which some cells in the body have XX chromosomes and others have XY chromosomes.
It is also possible for calico color to result from random mutations of skin cells in males, but this is the rarest cause.