All black cats are male

[snopes]

Comment: Are all black cats male?? I heard an "old wives tale" that if a
cat is completely black, it's a male.

[Beachlife!]

I've owned three black cats, all female.

[Mycroft]

I am willing to bet that all of your black cats had a few white hairs (I haven't checked with LLewtrah's site, but I think all black cats have a few white hairs)

[Wild Redhead]

We had an all black cat that was female when the kids were young.

[A Turtle Named Mack]

Originally Posted by Wild Redhead

We had an all black cat that was female when the kids were young.

And what sex was it when the kids got older?

[stalker]

Your female cats may look like they're black but if you look closely, I'm sure you'll see that they're very, very, very, very, very, very, very dark blue.

[Ariadne]

My female black cat does not have a single white hair. But she does look dark brown in bright sunlight.

[Mad Jay]

My all black cat is actually all white inside

[Beachlife!]

Originally Posted by Mad Jay

My all black cat is actually all white inside

All my cats appear to be all red on the inside.

[kismet]

Originally Posted by Beachlife!

All my cats appear to be all red on the inside.

You cut them open and LOOKED? I think there are laws against that.

When I look down his throat, my cat appears all black inside. He is tuxedo-patterned on the outside.

My mother and my ex mil both have female cats that are all black on the outside. I have not seen their insides.

[fitz1980]

I'm trying to remember stuff from some 14 years ago (when I took an HS class on genetics) but we did learn that the gene for fur color/patterns is on the X-chromosome in cats. That is why mostly all fertile calico cats are female, because they have 2 X-chromosomes; hence they can have 2 overlapping fur patterns. With male cats they either have one fur pattern or another, since they only have 1 X-chromosome.

It may be more common for male cats to be all black; since all a male cat needs is one "all black" X-chromosome (since he only has one X-chromosome) while a female cat would need both of her X-chromosomes to be "all black." It actually sounds like the same reason that color blindness is more common in male humans than female humans; but contrary to popular belief it's not only males who are color blind. There are women who are color blind; it's just much more common in men because that recessive gene is carried on the X-chromosome and men only have one. So a woman will only be color blind if both of her X-chromosomes carry that gene.

[RivkahChaya]

Originally Posted by fitz1980

It may be more common for male cats to be all black; since all a male cat needs is one "all black" X-chromosome (since he only has one X-chromosome) while a female cat would need both of her X-chromosomes to be "all black." It actually sounds like the same reason that color blindness is more common in male humans than female humans; but contrary to popular belief it's not only males who are color blind. There are women who are color blind; it's just much more common in men because that recessive gene is carried on the X-chromosome and men only have one. So a woman will only be color blind if both of her X-chromosomes carry that gene.

Ditto for hemophilia A, too.

It's rare for a female cat to be an orange tabby for some reason, too, isn't it? They exist, but aren't they outnumbered something like 20:1?

I have a black cat, and had a previous one, both female. I don't know anything about the parentage of this one, and she doesn't have any white that I can see (she's not being especially cooperative, though). The previous one had one white spot on her belly, about the size of a 5-cent nickel. Her mother was a pedigreed seal-point Himalayan, who managed to escape for a total of four hours. (Got spayed after that litter.) The owners suspect that her father was a black-&-white cat they saw hanging around. My cat had one littermate who was all black, with longish fur, but he-- and he was the only black male-- had white whiskers and eyebrows. It was very funny. He had a couple of pink spots on his paw pads, too. The litter, IIRC, consisted of a B&W male, 3 black females, the black male with the white whickers, and an all-gray female. Funniest part was that when the owners paid for Himalayan studs, the cat had a litter of 2 then just 1.

[llewtrah]

Originally Posted by fitz1980

I'm trying to remember stuff from some 14 years ago (when I took an HS class on genetics) but we did learn that the gene for fur color/patterns is on the X-chromosome in cats. That is why mostly all fertile calico cats are female, because they have 2 X-chromosomes; hence they can have 2 overlapping fur patterns. With male cats they either have one fur pattern or another, since they only have 1 X-chromosome..

Sorry, but only the gene for "orange" is on the X chromosome. All the other colours and patterns are governed by genes on the autosomes. The way the tortie pattern works is described here (and in a link from that page) and is due to something called X chromosome inactivation
http://www.messybeast.com/tricolours.htm

Black is caused by the non-agouti gene which is recessive to agouti. Agouti allows the tabby pattern to show up. Non-agouti suppresses the banding on the fur that would be the background colour. The same non-agouti gene causes all the solid colours except for white (white is caused by either the white spotting gene or the solid white masking gene, extremely rarely by albino since most feline albinos are "temperature dependent albino" i.e. Colourpoint (Siamese), Mink (Tonkinese) or Sepia (Burmese) patterns).

No idea where the "all black cats are male" idea is from as the usual old wives tale is that all ginger cats are male (in actuality only about two thirds of them are male and you can very easily selectively breed female ginger cats).

[llewtrah]

Originally Posted by RivkahChaya

It's rare for a female cat to be an orange tabby for some reason, too, isn't it? They exist, but aren't they outnumbered something like 20:1?.

Fitz1980 has confused black with orange. Black is a gene on an autosome, but orange is on the X chromosome and is epistatic over black (epistatic is like dominant, but the interacting genes are on different chromosomes, not different alleles on matching chromosomes). Orange females aren't rare either. About one third of orange cats (including orange and white cats) are female.

http://www.messybeast.com/quickfacts.htm#ginger

Black is on an autosome and manifests equally in males and females. Black tabbies (brown with black markings) and black-silver tabbies (silver with black markings) are also genetically black cats, but expressing the agouti gene.

[RivkahChaya]

Do cats get things like the human Kleinfelter's syndrome (XXY)? and if so, would that produce a cat with a female color pattern, like a calico or tortie, but with male genetalia, though probably not fertile?

Just a note: human males with Kleinfelter's usually are not fertile, but some are, and it's because it is possible to have Kleinfelter's mosaicism, or the XXY in just some cells, not all (which I think is true for most chromosomal mutations; it's true for Down Syndrome).

ETA: The 20:1 was a guess. My vet told me that orange tabbies were more likely to be male, and I pulled the 20:1 out of the air, because for some reason, I have only known one orange tabby that I knew for fact to be female, but I have known lots of boys. I have one right now, in fact. The biggest cat I ever knew was an orange tabby, and he was huge. He must have weighed 25 lbs, and it wasn't fat-- he was a little over-nourished, but he really was the size of a Beagle. I'm not kidding. His name was Rehnquist, but he was a really sweet, affectionate cat. He wanted to be picked up, that was the only problem.

[kitap]

Originally Posted by RivkahChaya

His name was Rehnquist, but he was a really sweet, affectionate cat. He wanted to be picked up, that was the only problem.

Back when Sandstone (my orange tabby) was still alive he was in for his annual check-up and shots and the vet told me that orange tabbies tend to be very sweet-natured kitties. Sandstone certainly was. He wasn't a lap cat but he could sit behind me on the couch back for hours, his paws draped over my shoulder and usually quietly purring.

[llewtrah]

Originally Posted by RivkahChaya

Do cats get things like the human Kleinfelter's syndrome (XXY)? and if so, would that produce a cat with a female color pattern, like a calico or tortie, but with male genetalia, though probably not fertile?

Just a note: human males with Kleinfelter's usually are not fertile, but some are, and it's because it is possible to have Kleinfelter's mosaicism, or the XXY in just some cells, not all (which I think is true for most chromosomal mutations; it's true for Down Syndrome).

If you follow the link I provided there are other links including a mosaicism article where there is case study of a Klinefelter cat. There are also chimeras (when two fertilised eggs with genetically different colours fuse into a single embryo) which can give a visually tortie male, but they are fertile (tat is also in the mosaicism article).

[llewtrah]

Originally Posted by kitap

Back when Sandstone (my orange tabby) was still alive he was in for his annual check-up and shots and the vet told me that orange tabbies tend to be very sweet-natured kitties. Sandstone certainly was. He wasn't a lap cat but he could sit behind me on the couch back for hours, his paws draped over my shoulder and usually quietly purring.

Oddly enough, over here there's a general belief in the opposite and gingers are seen as the "archetypal ginger tom" i.e. fighters!

I compiled various studies here
http://www.messybeast.com/colour-tempment.htm

[Lainie]

From Llewtrah's link:

However, the addition of white has a "calming effect" and tortie-and-whites are "not quite as temperamental as brindled to rties.The naughty tortie tag is not applied to dilute torties (blue-creams), possibly because they are less common in the moggy population.

Anecdotally, the naughtiest tortie I've ever known was a blue-cream whose dominant coat color was white. At the same time we had her, we had a another tortie-and-white, not dilute, with less dominant white but still large patches of it, who was extremely sweet. The blue-cream was far more intelligent, too, which I'm sure was a coincidence. She was smarter than any other cat I've ever met, actually, smart to a degree that was a bit disconcerting.

My daughter's calico can be very sweet at times, but "pissy" is probably the best word to describe her dominant personality. My ginger boy is a scaredy-cat, but sweet when you get past that. ETA: They're both dumb as rocks. We're reasonably certain which neighborhood tom fathered the calico, and we'd nicknamed him Doofus McStupidkitty for his habit of napping in the middle of a four-way intersection.

[Beachlife!]

My tortie is a very sweet cat to humans, but hates all other cats.