Physical
features
A cat grooming itselfCats typically weigh between 2.5 and
7 kg (5.5–16 pounds); however, some breeds, such as the
Maine Coon can exceed 11.3 kg (25 pounds). Some have been
known to reach up to 23 kg (50 pounds) due to overfeeding.
This is very unhealthy for the cat, and should be prevented
through diet and exercise (playing), especially for cats
living exclusively indoors.
In captivity, indoor cats typically live
14 to 20 years, though the oldest-known cat lived to age
36. Domestic cats tend to live longer if they are not permitted
to go outdoors (reducing the risk of injury from fights
or accidents and exposure to diseases) and if they are spayed
or neutered. Neutered male cats cannot develop testicular
cancer, spayed female cats cannot develop ovarian cancer
and both have a reduced risk of mammary cancer. Feral cats
living in modern urban environments often live only two
years, or less. Feral cats in maintained colonies can live
much longer; the British Cat Action Trust reported a 19-year-old
feral female. The oldest feral cat was Mark who was maintained
by the British charity Cats Protection and who reached 26
years of age.
Cats are athletic. Fast sprinters, they
are capable of reaching speeds of about 30 mph but only
for short distances. They can often jump vertically up a
fence or wall over 7 feet from stationary.The domestic cat
is one of the few four-legged animals that do not possess
rigid collarbones. This allows him to fit through an opening
about the size of his head.
Ears
A half-Siamese kitten showing the ears he inherited from
his mother.Thirty-two individual muscles in the ear allow
for a manner of directional hearing; [9] the cat can move
each ear independently of the other. Because of this mobility,
a cat can move its body in one direction and point its ears
in another direction. Most cats have straight ears pointing
upward. Unlike dogs, flap-eared breeds are extremely rare.
(Scottish Folds are one such exceptional genetic mutation.)
When angry or frightened, a cat will lay its ears back,
to accompany the growling or hissing sounds it makes. Cats
will also turn their ears back when they are playing, or
occasionally to show interest in a sound coming from behind
them.
Metabolism
An orange tabby taking a "cat nap"Cats conserve
energy by sleeping more than most animals, especially as
they grow older. Daily durations of sleep are various, usually
12–16 hours, with 13–14 being the average. Some cats can
sleep as much as 20 hours in a 24-hour period. The term
cat nap refers to the cat's ability to fall asleep (lightly)
for a brief period and has entered the English lexicon –
someone who nods off for a few minutes is said to be "taking
a cat nap".
Due to their crepuscular nature, cats are
often known to enter a period of increased hyperactivity
and playfulness during the evening and early morning, dubbed
the "evening crazies", "night crazies"
or "mad half hour" by some.
The temperament of a cat can vary depending
on the breed and socialization. Shorter haired cats tend
to be skinnier and more active, while cats with longer hair
tend to be heavier and less active.
The normal body temperature of a cat is
between 38 and 39 °C (101 and 102.2 °F). A cat is considered
febrile (hyperthermic) if it has a temperature of 39.5 °C
(103 °F) or greater, or hypothermic if less than 37.5 °C
(100 °F). For comparison, humans have a normal temperature
of approximately 37 °C (98.6 °F). A domestic cat's normal
heart rate ranges from 140 to 220 beats per minute, and
is largely dependent on how excited the cat is. For a cat
at rest, the average heart rate should be between 150 and
180 bpm, about twice that of a human.
Legs
A popular belief holds that cats always land on their feet;
they do usually—but not always. During a fall, a cat can
reflexively twist its body and right itself using its acute
sense of balance and flexibility. This is known as the cat's
"righting reflex." It always rights itself in
the same way, provided it has the time to do so during a
fall. Certain breeds that don't have a tail are a notable
exception, since a cat moves its tail and relies on conservation
of angular momentum to set up for landing.
Cats, like dogs, are digitigrades: they
walk directly on their toes, the bones of their feet making
up the lower part of the visible leg. Cats are capable of
walking very precisely, because like all felines they directly
register; that is, they place each hind paw (almost) directly
in the print of the corresponding forepaw, minimizing noise
and visible tracks. This also provides sure footing for
their hind paws when they navigate rough terrain.
Like all members of family felidae, with
the exception of the cheetah, cats have retractable claws.
In their normal, relaxed position the claws are sheathed
with the skin and fur around the toe pads. This keeps the
claws sharp by preventing wear from contact with the ground
and allows the silent stalking of prey. The claws on the
forefeet are typically sharper than those on the hind feet.
Cats can extend their claws voluntarily on one or more paws
at will. Cats may extend their claws in hunting or self-defense,
climbing, "kneading", or for extra traction on
soft surfaces (bedspreads, thick rugs, their owners etc.).
The curved claws may become entangled in carpet or thick
fabric, which may cause injury if the cat is unable to free
itself.
Senses
A close-up of a cat's eyeMeasuring the senses of any animal
can be difficult because there is usually no explicit communication
(e.g., reading aloud the letters of a Snellen chart) between
the subject and the tester.
While a cat's senses of smell and hearing
may not be as keen as, say, those of a mouse, they are superior
in many ways to those of humans. These along with the cat's
highly advanced eyesight, taste, and touch receptors make
the cat extremely sensitive among mammals.
Sight
Testing indicates that a cat's vision is superior at night
in comparison to humans, and inferior in daylight. Cats,
like dogs, have a tapetum lucidum that reflects extra light
to the retina. While this enhances the ability to see in
low light, it appears to reduce net visual acuity, thus
detracting when light is abundant. In very bright light,
the slit-like iris closes very narrowly over the eye, reducing
the amount of light on the sensitive retina, and improving
depth of field. The tapetum and other mechanisms give the
cat a minimum light detection threshold up to seven times
lower than that of humans. Variation in color of cats' eyes
in flash photographs is largely due to the interaction of
the flash with the tapetum.
The tapetum lucidum reflecting green in the pupils of a
cat.Average cats have a visual field of view estimated at
200°, versus 180° in humans, with a binocular field (overlap
in the images from each eye) narrower than that of humans.
As with most predators, their eyes face forward, affording
depth perception at the expense of field of view. Field
of view is largely dependent upon the placement of the eyes,
but may also be related to the eye's construction. Instead
of the fovea which gives humans sharp central vision, cats
have a central band known as the visual streak. Cats can
apparently differentiate among colors, especially at close
range, but without appreciable subtlety.
Cats have a third eyelid, the nictitating
membrane, which is a thin cover that closes from the side
and appears when the cat's eyelid opens. This membrane partially
closes if the cat is sick; although in a sleepy, content
cat this membrane is often visible. If a cat chronically
shows the third eyelid, it should be taken to a veterinary
surgeon.
Cats have a wide variation in eye colour,
the most typical colours being golden, green and orange.
Blue eyes are usually associated with the Siamese breed,
but they are also found in albino cats. If an albino cat
has two blue eyes, it is usually deaf; however, orange eyes
usually indicate the cat is free of hearing problems. Albino
cats having one blue and one orange eye are normally deaf
on the same side as the blue eye.
Hearing
Humans and cats have a similar range of hearing on the low
end of the scale, but cats can hear much higher-pitched
sounds, even better than dogs. Cats can hear 2 octaves higher
than humans, and one-half octave higher than dogs. When
listening for something, a cat's ears will swivel in that
direction; a cat's ear flaps (pinnae) can independently
point backwards as well as forwards and sideways to pinpoint
the source of the sound. Cats can judge within three inches
(7.5 cm) the location of a sound being made one yard (approximately
one meter) away - this can be useful for localizing prey
etc.

Smell
A domestic cat's sense of smell is about
fourteen times as strong as a human's. Cats have twice as
many smell-sensitive cells in their noses as people do,
which means they can smell things we are not even aware
of. Cats also have a scent organ in the roof of their mouths
called the vomeronasal, or Jacobson's, organ. When a cat
wrinkles its muzzle, lowers its chin, and lets its tongue
hang a bit, it is opening the passage to the vomeronasal.
This is called gaping, "sneering", or "flehming".
Gaping is the equivalent of the Flehmen response in other
animals, such as dogs, horses and big cats.
Touch
Whiskers clearly distinguishable on the wrist of even a
long haired catCats generally have about a dozen whiskers
in four rows on each upper lip, a few on each cheek, tufts
over the eyes and bristles on the chin. Whiskers may also
be found on the cat's inner "wrists", and there
are similar hairs which make up the cat's eyebrows. The
Sphynx (a nearly hairless breed) may have full length, short,
or no whiskers at all.
Whiskers (technically called vibrissae)
can aid with navigation and sensation. Whiskers may detect
very small shifts in air currents, enabling a cat to know
it is near obstructions without actually seeing them. The
upper two rows of whiskers can move independently from the
lower two rows for even more precise measuring.
It is thought that a cat may choose to
rely on the whiskers in dim light where fully dilating the
pupils would reduce its ability to focus on close objects.
The whiskers also spread out roughly as wide as the cat's
body making it able to judge if it can fit through an opening.
Whiskers are also an indication of the
cat's attitude. Whiskers point forward when the cat is inquisitive
and friendly, and lie flat on the face when the cat is being
defensive or aggressive.
Taste
According to National Geographic December 8, 2005 cats cannot
taste sugary foods due to a faulty sweet receptor gene.
Some scientists believe this is related to the cat's diet
being naturally high in protein, though it is unclear whether
it is the cause or the result of it.
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