It is difficult to house male mice together without the risk of injury to one or both males.

Normal male mice do not go bald as they age, but the research could still be significant for human beings.

Some people, however, prefer the personality and curiosity of male mice.

When given the opportunity, male mice tend to direct their urine in the female's direction.

Male mice show great variation in behavior over time.

Male mice tend to have a stronger odor than the females.

Male mice are easiest to vasectomize at about 6 weeks of age before they become fat.

Male mice displayed the same pattern of altered behavior, which varied with age, she said.

In this latest case, male mice were raised on a low-protein diet.

This lifespan extension, of about 15-16 percent, is observed only in male mice.