Question

How can you differentiate between a male and female rat from the external features?

Answer 1

According to the biological approach, there is no difference between sex and gender, so biological changes causes gendered behaviour. Hormones and chromosomes are the two biological factors that decide gender.

Complete answer:
Gender variations in the genitalia of mice and rats are used to classify them. Females have mammary organs (some with visible areolas) and a vaginal opening with an observable clitoris, while males have testicles and a penis. While these characteristics are readily discernible in reproductively active males and lactating females, they can be more difficult to detect in non-reproductively active species.
The scrotum is a distinguishing feature that helps you to say the difference between a male and female rat. Female rats do not have a scrotum, while male rats do.
Females who aren't reproductively active and don't have noticeable areolas can be difficult to classify, particularly because their clitoris mimics a penis. The anogenital gap can be used to sex creatures where areolas or testicles are not visible and there is no sexual difference in shading or scale. The distance between the base of the penis and the butt (male) or the clitoris and the rear-end (female) is known as the anogenital distance (female). Females have a smaller anogenital gap than males.

Note:
Females have five sets of mammary organs and areolas from around 10 days; males have no areolas. The presence of balls on the guys is the most striking and clear contrast at the point when explicitly developed. These are massive in comparison to the rest of the body and can be withdrawn into the body.