It could be true that the world is divided into two types of workers. Type A workers are the compulsive, competitive strivers who live to work. They would agree with Noel Coward: "Work is more fun than fun."

Type B people live each day at a time. Work is just a necessary part of the mix of life. They work to live. They would agree with Peanuts cartoonist Charles M. Schulz: "My life has no purpose, no direction, no aim, no meaning, and yet I'm happy. I can't figure it out. What am I doing right?"

Labor Day celebrates the contributions of all workers, whatever type, by (ironically) giving them a day off. It is one Monday that is not blue.

Efficient workers make their contributions speedily. They exist in both groups. There is the Type A person who throws himself -- heart, soul and overtime -- into his job. He contrasts with the Type A person who races into work, spins his wheels there, sprays mud all over everyone else and then sinks into a rut.

A Type B person, unthreatened by failure or success at his job, can execute it well without great emotion and wasted effort. He is offset by the Type B person who simply does not care, collects a salary for a minimum output and stores up his energy and time for fun after work.

Considering us as a species, though, it is only a fairly efficient animal who can work 30 to 40 hours a week (perhaps 25 of that flat-out) to cover all its needs and an incredible array of niceties.

Most other animals work much harder. Their biggest job is finding enough to eat. It can be a full-time preoccupation.

Take the shrew. One of the smallest mammals, some mice outweigh them by a factor of six. A shrew is so small that it must eat its own weight each day just to stay alive. A pregnant shrew may eat more than three times its weight daily.

Shrews usually fill up on insects, though they mix in salamanders, worms, frogs, shellfish and vegetation. Driven by hunger, a shrew will attack a mouse twice its size. With this kind of appetite -- shrews can starve if they go without a meal for two or three hours -- they take no holidays. They hunt every day, all day, all year.

North America's smallest mole, called the shrew mole, may surpass even the shrew. It is three inches long. One shrew mole under close observation ate 1.4 times its weight in only 12 hours. Food gallops through them in 40 minutes. (This takes compulsive snacking to its horrible limit.)

To put appetite and work in another perspective, one thinker calculated that, each year, British spiders eat in insects the equivalent to the weight of the entire human population of the British Isles.

For most food-storing animals, intense work is seasonal. The pocket mouse can gather, and store in its cheek pockets, 3,000 mustard seeds in one hour. One burrow belonging to a kangaroo rat contained almost 14 bushels of seeds and dried grasses. It was an orderly larder: The rat had cut the grass to short lengths and had carefully sorted the seeds according to kind.

The eastern chipmunk is another energetic food gatherer. It can fit 32 beechnuts, or 13 prune pits, or 3,700 blueberry seeds in its cheek pouches. Six quarts of nuts and seeds are a reasonable underground cache for winter. However, when one chipmunk's cupboard was raided by researchers, they turned up 478 acorns and 2,734 cherry pits. Another chipmunk's supply consisted of 167 hazelnuts and several thousand cherry pits.

The eastern mole does considerably more muscular work. Using its 8-inch body and weighing perhaps 4 ounces, this creature nevertheless excavates huge mounds of earth as it digs its tunnels. With its large palms, one mole pushed a tube of earth that was 35 times its own weight. To match that, a full-grown man would have to move 5,000 pounds of dirt.

If moles are the underground construction workers, marmots take their tunneling a step further. This relative of the woodchuck is also a home insulator. One marmot's burrow, being readied for hibernation, contained 30 pounds of hay, much of it used to line the tunnel for that cozy winter feeling.

To feed and shelter oneself can be exhausting. But feeding offspring can be the hardest work of all. (Compared with many species, mammalian mothers are fortunate; at least they have the convenience of a built-in milk dispenser.) The Bembix wasp feeds each of her larvae -- and she may have six of them -- some 80 flies a day. She carries on this schedule for 15 days.

A worker honey bee can collect, in one day, nectar from 250,000 flowers. One pound of nectar can represent 300,000 miles of flight. An "empty" worker bee weighs about 80 milligrams. Loaded down, it flies with approximately 70 milligrams of nectar. That's the equivalent of our jogging with our weight in groceries strapped to us. (It would be a demonic but fitting deterrent to overshopping and overeating.)

A pair of English robins made 29 visits each hour to satisfy the appetites of their hatchlings. They carried two or three caterpillars on each trip, with a catch at day's end of 1,000 caterpillars. Similarly, a pair of American house wrens fed their chicks 1,117 times a day. (This makes it exhaustingly clear why most humans cannot keep baby birds alive. We just can't collect enough insects, never mind regurgitate them.)

Flying mammals also put in some hard hours. A mother bat usually carries her newborn young during nighttime hunts for moths and other insects. Hoary bats continue the practice until their young are about half grown. One mother apparently was reluctant to say no to her youngsters. She made several efforts to take off, only to be grounded by the two whose weight exceeded her own by 25 percent. She finally deposited them in a tree and flew off alone.

Animals even do housework. One species of badger which lives in the Austrian Alps collects moss, ferns and leaves for bedding. It carries the bedding to its burrow and, using its snout and front legs, pushes it into the right chambers: its bedroom and nursery. A few days later, the same badger will push the bedclothes out the front door and leave them in the sunshine for a few hours. Then the meticulous mammal bundles them back into the burrow -- the animal version of airing the blankets.

And for some creatures (commuters will identify with this), merely getting to work is arduous. The midge, a small member of the mosquito family, beats its wings 1,000 times a second simply to stay aloft.