How can you distinguish a male rat? - briefly
Male rats have a distinct genital papilla and a wider, more rounded anogenital distance than females. The presence of scrotal testes also confirms a male specimen.
How can you distinguish a male rat? - in detail
Rats exhibit clear sexual dimorphism that allows reliable identification of males. External characteristics provide the most immediate clues.
- «Anogenital distance» is noticeably greater in males, often exceeding twice the length observed in females.
- Presence of a scrotum housing visible testes distinguishes males; the scrotal sac appears as a firm, rounded bulge beneath the tail.
- Body mass typically exceeds that of females of comparable age, with broader shoulders and a more robust skull.
- Fur coloration may differ in some strains, with males displaying slightly darker dorsal pelage.
Behavioral observations support morphological assessment. Males frequently engage in territorial marking, deposit urine patches, and display heightened aggression toward conspecifics. Vocalizations during mating encounters are more frequent in males.
When external examination is inconclusive, internal methods are available. Palpation of the abdomen can reveal enlarged testes in mature individuals. Ultrasound imaging confirms testicular presence without invasive procedures.
Molecular techniques provide definitive verification. Polymer‑chain‑reaction assays targeting Y‑chromosome specific sequences, such as the Sry gene, yield positive results exclusively in male specimens.
Combining morphological measurements, behavioral patterns, and, when necessary, diagnostic imaging or genetic testing ensures accurate differentiation of male rats.