Male tortoiseshell cats have feminine personality traits as described below. We know that the chances of finding a male tortoiseshell cat are very rare. I’ve seen various estimates as to their rarity. The lowest figure I’ve seen is about 200 to 1 and the highest about 10 times that or more. We also know that the tortoiseshell cat coat is sex-linked.
Why males can be torties
Normally only a female kitten can display black patches inherited from one parent and red tabby patches inherited from the other. The reason is that the genes controlling these colours are both carried on the X chromosomes. The red gene on one chromosome and the non-red gene is on the other. Only females have 2 X chromosome. Therefore only females can display the red and non-red tortoiseshell combination. Male cats have one X chromosome and one small Y chromosome. On their single X chromosome they carry either the red or the non-red gene but they can’t have both. Therefore, they are either a red tabby or allover black cats.
The reason why sometimes male cats can be tortoiseshell cats even though it is theoretically impossible is because a minor genetic error occurs and the male cat develops with a genetic combination XXY. The double X chromosome gives the cat a chance to be red and black and the Y chromosome gives the cat male characteristics. But Dr Morris says that the masculinity of these cats leaves a lot to be desired to use his own words. Male tortoiseshells are sterile and their behaviour is, he says, extremely odd. He says that they act like a “masculinized female” rather than a true male cat.
Feminine male tortoiseshell cat
He refers to one particular male tortoiseshell cat who was observed in a colony of cats. This cat had feminine personality characteristics. He was ‘nonchalant’ in his interactions with other cats. He disdainfully ignored the usual status battles which occur between male and females. There was little fighting along gender lines. Dr Morris refers to these male tortoiseshell cats as neither fully male nor fully female and therefore they do not feel the need to compete in pecking-order disputes over females.
With respect to spraying urine which is typical of unneutered male cats he did not start to do this is at the usual age. Also he did not attempt to mate with females in heat although he had the required anatomy to do so. He allowed young tom-cats to mount him and attempt to mate with him.
When this cat became older he showed some interest in females and wanted to mate with a few but not with real enthusiasm. He sprayed urine in a “desultory fashion”. At no stage did he behave like a proper tomcat. When he was kept isolated with a highly sexualised female cat he did mate with her several times but the female did not become pregnant, confirming his infertility.
There are some superstitions regarding male tortoiseshell cats. Apparently in Celtic countries it was considered a good omen if one decided to live in your home. And in England they believed that warts could be removed by simply rubbing them with the tail of a tortoiseshell tomcat during the month of May. I wrote a page about the value of male tortoiseshell-and-white cats and the argument is that they aren’t valuable because of their infertility. However, Japanese fishermen pay huge sums for a tortoiseshell tomcat to keep as a ship’s cat. They believe (or believed) that male torties protect the crew from the ghosts of their ancestors and the vessel from storms.