1.   Male Wistar rats were used as the experimental animal.

2.   Male rats were obtained from Charles River Laboratories.

3.   Accordingly, male rats failed when challenged to perceive quick changes in sound, while the females could process the rapidly alternating tones normally.

4.   By picking all male rats for a study, you filter down to a very homogeneous group.

5.   Female rats are better able to breathe in low oxygen than male rats, especially when their progesterone levels are highest.

6.   Four of the astronauts collaborated in the dissection of nine adult male rats, preserving the brain and other tissues responsible for balance, navigation and coordination of movement.

7.   Further research showed that the tumors were caused by crystals growing in the bladder, perhaps because male rats have an unusual urine chemistry.

8.   In studies, male rats showed much more muscle damage after exercises that emphasized muscle extensions than did female rats.

9.   Researchers from the Johns Hopkins University School of Medicine in Baltimore have completed a study in which they gave male rats estrogen before inducing strokes.

10.   Scientific studies have demonstrated that male rats exposed to the pesticide before and shortly after birth can suffer effects like malformed genitalia.