The genetics of calico cats are complicated and I don’t pretend to fully understand the science. You can read up about it on Sarah Hartwell’s website messybeast.com [link]. In answering the question in the title, the story of the health or otherwise of calico cats comes down to their gender and the chromosomes inherited from their parents.
ASPCA Pet Health Insurance tells us that being a calico cat does not impact the cat’s longevity if they are female. Female calicos have a lifespan typical of any domestic cat which is 15-years-of-age or more.
Sadly, the typical lifespan of a domestic cat does not apply to a male calico, or tri-colored, cat. In rare cases, a male cat can inherit two X chromosomes in addition to his Y chromosome. They have XXY chromosomes and, as I understand it, they often suffer from Klinefelter’s Syndrome and as a consequence they live shorter lives. Male calicos are rare.Symptoms of this condition include:
- Cognitive and developmental issues which can lead to behavioural problems and;
- Reduced bone mineral content which can result in a higher risk of broken bones and;
- Increased body fat which can lead to diabetes, heart disease and joint pain.
About Klinefelter’s Syndrome
On the messybeast.com website, Sarah Hartwell states:
According to Roy Robinson’s ‘Genetics for Cat Breeders’ out of 125 kittens produced by black female x orange male there was 1 tortoiseshell male. The majority of calico or tortoiseshell males studied were from tortoiseshell/calico females and were either XXY (Klinefelter) or XXXY (chimera) genetic make-up
Sarah refers to a lady, Laura K Baker, from Dublin, Ohio, USA who lived with a male tortoiseshell Klinefelter ‘giant’ who they called Brody Baker. A veterinarian who checked Brody said that he wouldn’t live long. Brody had misshapen feet and legs and a shattered hip. He had distinct calico markings and male anatomy. I’m not sure what fatal condition he suffered from, however.
Klinefelter’s Syndrome in humans
In people, Klinefelter’s Syndrome does not usually cause any obvious symptoms early in childhood and sometimes the later symptoms can be difficult to recognise. It causes an inability to have children naturally due to infertility and a low sex drive. When they become teenagers their anatomy becomes slightly abnormal if that’s not the wrong language to use; such as poor muscle tone, broad hips, growing taller than expected with slower than usual muscle growth. Children with this condition are also shy and suffer from low confidence. When they are toddlers they learn to crawl and walk later than usual in addition to being quieter and more passive.
You’ll have to translate that human description to how it might affect the domestic cat suffering from this rare condition.