The rat population may soon face an unemployment problem if Harold M. Ross. teaching fellow in Anthropology finds out how to mass-produce tree shrews for use as laboratory animals.

Ross and five Harvard undergraduates are conducting experiments at the New England Regional Primate Research Center in Southboro, Mass., to determine the ideal artificial breeding conditions for the shrew.

The tree shrew is a small animal which some consider to be a primate. This Southeast Asian creature could be confused with a squirrel except for its protruding snout.

If the tree shrew, can be mass bred in captivity, it will be as inexpensive as the rat as a laboratory animal. And it is much nearer to human beings on the evolutionary scale.

To determine the ideal breeding conditions. Ross is making 73 shrews reproduce under various controlled laboratory conditions -- different types of cages, different numbers of animals per cage, different lighting. The experiments, stared in March, will begin to bear fruit in mid May when the shrews' gestation period ends. But Ross believes it will take about a year to determine a solution to the mass-breeding question.

Ideally, Ross said apes and monkeys should be used in experiments if applications to human beings are desired. But the cost of obtaining and maintaining apes and monkeys is prohibitive.