Lines I Wished I’d Written: How the Cat Works

I have not been reading much this whole summer.  I’ve gotten lazy and the evenings are taken up with following baseball, my sports love.  But I have been reading the ASPCA Complete Guide to Cats, and found an interesting and well written chapter titled, “How the Cat Works.”  I’ll post some parts of the chapter, subsection’s title which I put in bold.

How the Cat Works

In the words of Leonardo da Vinci, “the smallest feline is a masterpiece.”  The cat is one of nature’s most elegant examples of form following function.  The design of the feline physique is perfectly suited to a predatory carnivore’s needs: detecting, pursuing, catching, killing, eating, and digesting prey.  In fact, the cat’s basic form has changed relatively little since wildcats first appeared some 30 million years ago.  The many species that now inhabit the world’s jungles forests, deserts, couches, and armchairs all follow the same basic blueprint.  Although most domestic shorthairs aren’t likely to catch anything more exotic than a few extra hours of sleep, today’s pet cat is built very much like its wild relatives.

Framework: Bones and Muscles

As any cat owner knows simply by watching, the cat is built for grace, flexibility, and power.  From a sitting start, it can jump up to nine times its own height.  It can make its chest and shoulders narrower, to squeeze through almost impossible tight spaces.  It can sleep curled into the shape of a letter O and, immediately upon awakening, stretch and form an inverted C, pressing the chest almost to the floor.

Sinuous Spine

Where does the cat get its remarkable elasticity, both in motion and at rest?  The first place to look is the animal’s spine.  Because cats’ vertebrae are flexibly connected and have particularly elastic cushioning disks between them, the feline spine is extremely supple.  A cat’s ability to right itself in midair so that it can land on its feet and to make rapid changes in direction while pursuing or capturing prey are both made possible by the flexibility of its spine. 

The flexibility of the cat’s spine also contributes to its fluidity and speed as a runner.  To reach top speed—about thirty miles an hour—a domestic cat depends on its spine as much as its feet and leg muscles.  When running, cats can lengthen their stride, and thus increase their speed, by alternately extending and flexing their vertical column.  When the cat’s feet push off to start a new stride—the claws serving as spikes for traction—the cat’s body stretches to its maximum length.  The cat’s running style thus resembles a series of elongated jumps or bounds.  The cat increases its speed by lengthening its stride with each bound, until every stride carries it about three times the length of its own body.  Many other mammals, especially humans, rely on a more pistonlike sprinting style, in which the key factor is how often the feet make contact with the ground.

Stretching and Squeezing

Another special feature that contributes to feline flexibility is the tiny, rudimentary collarbone, which helps cats lengthen their stride when sprinting by allowing them to extend their forelegs fully.  The lack of a long, anchored collarbone (as humans have) gives cats the ability to squeeze through tight openings by literally compressing themselves to fit the available space.  Moreover, the feline shoulder blade is attached to the rest of the body only by muscles, not bone.  This gives the shoulder blade tremendous freedom to move as the cat moves, enhancing the cat’s flexibility and grace and extending its long running stride. 

Legs and Toes

Whether running or walking, cats land on their toes.  Such digitigrade locomotion is the hallmark of a sprinter.  Animals that land on their full soles of their feet, using plantigrade locomotion, are better suited to sustain exertion.  Bears and humans, for example, have a plantigrade footfall.  Cats hunt using great bursts of speed (after which they often end up panting). 

The spring in a cat’s legs is phenomenal, thanks in part to the construction of its hip, knee, and ankle joints.  These joints have very little give from side to side.  They are very stable and strong and can withstand great force applied in one direction: forward.  When the cat’s hind leg muscles contract, the three joints extend in an instant, giving the animal enormous thrust to carry it either high or far.  The cat’s landing is cushioned by the thick pads on its feet, and by the bones of its feet and wrists, whose intricate construction makes a stable two-point landing on its forepaws possible. 

Explosive Power

One look at a cat in profiler provides an obvious clue as to why cats are such marvelous, explosive athletes.  In proportion to its overall body size, a cat’s hindleg muscles are enormous, as is its “launching pad,” an exceptionally long rear foot.  These anatomical features translate into tremendous power and mechanical advantage when a cat springs or leaps.

The cat’s particular type of athleticism may also come partly from many “fast-twitch-fatiguing” cells contained in its skeletal muscles.  As their names suggest, these cells produce explosive movement, but they use up their energy stores in a flash and tire easily—as does the cat, which has relatively few “slow-twitch” fibers to give it endurance.

Energy Conservation

Because cats lack the staying power of plantigrade long-distance runners, conserving energy is a must for them.  Even the way a cat walks can save energy, as the contralateral gait cats sometimes use—left hindfoot moving more or less in tandem with the right forefoot, and right hindfoot moving with the left forefoot—is mechanically very efficient.

The best energy-saving strategy, of course, is to stay put, and cats are masters at it.  Their brain chemistry makes it possible for them to spend more of their time asleep than awak.

Lightning Fast Nerves

When cats are awake, an intricate network of nerves radiating from the brain and the spinal cord operates in high gear, receiving and transmitting information and governing sensations, reflexes, and motor functions throughout the cat’s body.  The lightning speed at which the cat’s nervous system operates is illustrated by the well-known feline “righting reflex.”  Thanks to this and its remarkable flexible spine, a cat held feet upward and dropped will have its feet pointed downward, ready to land, before it has fallen twenty-four inches.

Dexterity

A cat’s wrist bones and their associated tendons and ligaments give the cat a measure of manual dexterity—not close to matching our own, or even a raccoon’s but enough to enable the cat to get mice out of hiding places (or food out its dish) with a handlike scooping motion and to hold onto trees.  This ability to pronate the wrist (carpus)—turn the bottom of the paw toward the midline of the body—is not common in the animal kingdom.  But then, neither are most creatures as graceful and nimble, yet powerful, as cats.

That’s enough for now.  Isn’t that fascinating?  It reminds me of an engineering project, only thing God being the engineer. 

Let me end this with a recent picture of Tiger, here sitting on the windowsill.  That sill is a good three feet off the ground and he makes a smooth calculated leap onto that less than two inch ledge. 

Isn't he a handsome kitten?  He's four months old now, and that picture was snapped three weeks ago.  I had to put a stop to him going on that ledge.  Early one morning, while the birds were chirping out there in the trees, he climbed up the window screen to the top.  It’s a good thing the screen didn’t fall out.