The higher they are, the easier they fall, sometimes.

In what sounds like a joke from a Gary Larson Far Side cartoon, veterinarians are studying how cats can survive falling off buildings.

Oddly, the higher the building, the greater a cat`s chance of survival-if the building is at least seven stories high.

Ninety percent of cats survived falls from skyscrapers and open windows in New York, according to an article published in the April 14 issue of the British journal Nature.

In a study of 132 fallen felines, veterinarians W.O. Whitney and C.J. Mehlhoff found:

- The worst-cat scenario involved a feline that plummeted 32 floors onto solid concrete. It ''was released after two days of observation in the

(animal) hospital, having suffered nothing worse than a chipped tooth and mild pneumothorax,'' a type of lung injury, said physiologist Jared Diamond of the Medical School at the University of California in Los Angeles.

- Seventeen of the cats were put to death by owners who couldn`t afford treatment. Of the remaining 115, 104 survived.

- The higher the building, the greater the rate of deaths and injuries-until the seventh floor, above which the rate declined.

In contrast, ''few adults survive falls of more than six stories onto concrete,'' Diamond said in an article reviewing Whitney and Mehlhoff`s research.

Why the difference between cats and humans? And why the seventh-story reversal in death rates for cats?

Diamond said several factors, including mass and surface area, control how a falling creature hits the ground. Falling large animals, such as humans, are more injury-prone than small ones.

''Even a small drop breaks an elephant`s leg,'' Diamond said, ''but falling mice reach terminal velocity in the atmosphere much sooner and at a much lower value than do falling elephants.''

Speed of descent also is important. A falling cat reaches a maximum, or terminal, velocity of 60 miles an hour after dropping 100 feet, compared with 120 miles an hour for humans.

Diamond also noted that on reaching terminal velocity, a cat ''may relax and extend the limbs more horizontally in flying-squirrel fashion.''

This would succeed in ''not only reducing the velocity of fall but also absorbing the impact over a greater area of its body.''

Falling cats have superb body control ''and make gyroscopic turns such that all four feet are soon pointing downward. . . . Hence cats dissipate the impact force over all four limbs.''

Thus, Diamond said, in cases involving considerable heights-higher than seven stories-a cat has more time to relax and spread out.

In contrast, he said, ''falling human adults tend to tumble uncontrollably but land most often on two feet, (and) next most often on their heads.''