Biology Reference
In-Depth Information
Some breeds of cats developed because they were selectively bred
to emphasize conformational differences of certain bones. The most
popular of these is the Persian, with its round skull and flattened,
brachycephalic face. Burmese and Himalayans are other breeds that
share the “pushed-in nose” look. (You may think of the skull as one
unique bone, but this is not the case. Cats have 29 different bones that
make up the skulls.)
Different numbers of tailbones characterize some breeds. Most cats
have between 18 and 20 caudal vertebrae that make up their tails. Manx
cats have far fewer, and are considered “rumpys” or “stumpys,” based on
how much of a tail they have. Their lack of tail is due to an inherited
dominant trait. Japanese Bobtails and Pixie Bobs are other breeds with
shorter-than-average tails.
Another tail defect is a congenital kink. Many cats are born with
kinks in their tails, and this is considered a recessive trait.The kink can
come from trauma at birth (or immediately following), or it can just be
the way the kitten turned out. Most owners think the kinky tail gives
their cat character.
A polydactyl cat is one who has extra toes, and this trait results from
an autosomal dominant gene. Domestic cats have 19 pairs of chromo-
somes. Eighteen pairs are autosomal , meaning nonsex-determining chro-
mosomes, while the last pair are the sex-determining sex chromosomes.
Some cats have extra toes on their front feet and some have extras
on all four feet. Polydactyl cats need more help keeping their nails short
because the extra nails usually do not get worn down during normal
activity. Unclipped nails that
continue to grow will actually
penetrate into the footpads,
causing pain and infection.
Humans can also be born
polydactyl. Throughout history,
people with extra fingers were
considered to be witches. Anne
Boleyn, one of Henry VIII's
wives, had six fingers on one
hand. She was decapitated fol-
lowing accusations of adultery,
before a strong witchcraft case
could be made against her.
Polydactyl cats can be awfully cute.
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