Ginger cats have always stood out, not just because of their bright orange coats, but because they are mostly male. For years, cat lovers and researchers alike have been scratching their heads over this odd pattern. Now, two science teams have cracked the code.
It turns out that ginger cats owe their color to a rare mutation on the X chromosome. This change affects a gene called ARHGAP36, flipping a genetic switch that makes the cat’s coat orange. The mutation doesn’t change the gene directly, but removes a chunk of DNA near it.
This missing segment normally keeps the gene quiet in pigment cells. Without it, the gene fires up and produces more pheomelanin, the pigment that gives red and yellow tones.
Freepik | Males (XY) need only one copy of the mutated X chromosome to be fully orange, while females (XX) require two copies. Hence, 80% of ginger cats are male!
Most mammals don’t have this issue. The mutation is unique to domestic cats. No wild cats, no dogs, no people. Just our house cats. And it has been around a while. Ancient art from as far back as the 1100s shows calico cats, which also carry the orange gene.
So, why are ginger cats usually male? It turns out it is the X chromosome. Males have one X and one Y. Females have two Xs. If a male inherits the mutated X, that is enough to make him orange all over. A female, on the other hand, needs both X chromosomes to carry the mutation. If only one X is mutated, she ends up with patches, the classic calico or tortoiseshell look.
That is why about 80% of ginger cats are male. Females with two mutated Xs are rare. Female cats usually end up with only one copy, giving them that mix of colors.
Researchers had suspected this was an X-linked trait for years. The sex ratio gave it away. But no one knew which gene was involved until now. Two separate teams, one from Stanford University and the other from Kyushu University in Japan, found the answer in the same place: ARHGAP36. The findings were published on May 15 in Current Biology.
The discovery also revealed something unexpected. This gene isn’t just active in skin cells. It is more commonly found in the brain and hormone glands. That raises some curious questions. Could this gene affect more than just fur color? Maybe even behavior? People joke about orange cats being a little wild or “silly,” but science hasn’t found proof of that yet.
Hiang Kanjinna / Pexels | So, why are ginger cats usually male? It turns out it is the X chromosome.
However, what makes this mutation even more interesting is how it works. In humans and most other animals, pigment mutations usually happen inside the coding part of a gene. They change how the pigment is built. But in ginger cats, the mutation hits a non-coding area. It doesn’t build pigment itself. It tells the pigment-producing cells when to turn on the gene.
Since ARHGAP36 also plays a role in human biology, especially in skin and hair conditions, this new cat research might help scientists understand similar issues in people, like skin cancer or hair loss.
The mutation likely showed up early in cat domestication, which makes sense. Humans love color and pattern. A bold orange cat would have stood out in any village or marketplace. People may have picked them on purpose, giving the gene a boost across generations. Over time, the orange coat became a familiar sight.