If it is a jungle out there, it is dying.

The gray wolf, the mountain gorilla, the California condor -- if Noah had to build his ark today, he could probably get by with a compact.

So many species are dwindling toward extinction that scientists expect 2 million to disappear by the end of the century. In some parts of the world, especially in the vanishing rain forests, one species enters oblivion every day.

The crisis is not only a distant one: At the Baltimore Zoo, the giraffes have been cut down by a mysterious virus. In the voyeuristic company of man, the giant panda at the National Zoo has lost the instinct for reproduction. The poor Fairfax flatworm wound up in an asphalt overcoat.

Now it seems that the kangaroo, three major species of which are still on the Interior Department's list of endangered species, is back on the butcher block because the U.S. government has refused to reimpose a ban on the importation of roo products.

Sue and Graham Bicknell, of the International Fund for Animal Welfare- Australia, have repeatedly barnstormed the United States, armed with photographs of one night's work by a professional roo hunter.

Like deer out of season, roos are hunted at night when they come out to eat. Blinded by spotlights mounted on high-bed pickups, they are beheaded and eviscerated on the spot, then the whole catch is hauled, unrefrigerated, back to town.

The Bicknells say that the United States and Australian governments are playing politics with the pouchy roos, trading off the import ban and American B-52 basings.

There is also anti-roo pressure from the big agricultural lobbyists, especially the sheep farmers, who begrudge the roos the grasslands. (It is said, too, that kangaroos have a positive genius for destroying boundary wires.)

As an export item, kangaroo hide can be worth millions of dollars a year. Baseball players and other professional athletes place a premium on roo leather shoes, which are exceptionally sturdy and flexible. High-fashion accessories designers here and in Europe use roo not only for shoes and belts, but for cute bar accessories. Roo meat is used for pet food and the specialty meats industry (and shows up periodically disguised as venison).

Official Australian figures about the size of the kangaroo population are admittedly a little loose. Two years ago, it estimated 60 million roos; a year ago, it shifted to 19 million. A year ago, the Bicknells say, the Australian government muttered something about 10 million, and animal welfare groups fear the real population may be only 6 million. (A U.S. Interior Department senior biologist has concluded there are about 30 million, reassuring the importers.)

In any case, at a rate of 15,000 males, females and "joeys" a night -- and the Bicknells' estimate is in line with the figures put out by roo-steak promoters back before the kangaroo became a political animal -- the population may not last long.

Man has a special responsibility to the animal kingdom. While the natural pecking order is based on size, man, in such select company as the boa constrictor, has learned to kill and consume animals larger than himself in order to ensure his place at the receiving end of the food chain. He has also learned to kill for reasons other than need, and that makes him, as the only conscious killer species, doubly responsible for devising some coherent animal protection policy.

So far, Americans have tended to be piecemeal protesters. In place of so many epitaphs, we print bumper stickers. The cow-eyed whale, the beatific baby seal, the mannish mountain gorilla strike our soft spots one after another. Nevertheless, we let animals pass from endangerment to extinction.

We have too much faith in our fondness for animals. They look well-fed and safe enough in the zoos (the Bicknells, in fact, thought the kangaroos at the National Zoo were the "sleekest, healthiest" ones they'd ever seen). Despite the warnings of a shrinking wilderness, we smile at the movies of antelope and zebras and leopards thundering across Africa.

And we might suppose the kangaroo is so much a part of the Australian image -- its coat of arms, its tourist advertising -- that it could ever be allowed to become extinct.

Pull the change out of your pocket and look at the bison on your old nickels, the eagle on your quarters. They're probably the only ones you'll ever see.