How can I tell the sex of a two‑month‑old rat? - briefly
Examine the animal’s underside: males display a greater anogenital distance with a visible scrotal sac, while females have a shorter distance and a distinct vulvar opening. These physical cues reliably indicate sex in a two‑month‑old rodent.
How can I tell the sex of a two‑month‑old rat? - in detail
To identify the gender of a juvenile rat around eight weeks old, examine the external genital region from a ventral perspective. Use adequate lighting and, if necessary, a magnifying lens to enhance visibility.
First, gently lift the animal’s tail to expose the area between the anus and the genital opening. In males, two small, oval-shaped testes lie within a scrotal sac just posterior to the penis. The testes may appear as faint, pale bulges beneath the skin; they are often more evident when the rat is warm or slightly stimulated. A preputial fold surrounds the penis, and the distance between the anus and the genital opening (anogenital distance) is typically longer than in females.
In females, the genital opening consists of a simple slit without a surrounding scrotal sac. The area lacks visible testes, and the anogenital distance is shorter. The presence of a pair of small, round openings (vulvar lips) may be observed, although they can be subtle at this age.
If visual cues are ambiguous, palpation can assist. Gently press the region with a fingertip; a male will present a firmer, more rounded mass corresponding to the testes, while a female will feel smoother and lack any distinct bulge.
Record observations for each animal to ensure accurate sex determination, especially when planning breeding or experimental groups.