What does a three-month-old rat look like? - briefly
A three‑month‑old rat measures approximately 10–15 cm in body length with a tail of comparable length, weighs around 120–180 g, and exhibits adult fur coloration and fully developed incisors. It has reached sexual maturity and displays the typical body proportions of a mature laboratory rat.
What does a three-month-old rat look like? - in detail
A rat that is approximately three months old displays characteristics of late juvenile development, approaching sexual maturity.
The animal typically measures 9–12 cm (3.5–4.7 in) in body length, excluding the tail, and weighs between 120–180 g (4.2–6.3 oz). The tail adds another 15–20 cm (5.9–7.9 in) and is proportionally slender, often slightly longer than the body.
Fur is fully developed, dense, and may exhibit the color pattern inherited from its parents—common shades include black, brown, gray, white, or a combination thereof. The coat is smooth to the touch, with no juvenile shedding patches.
Head morphology includes a rounded cranium, prominent whiskers (vibrissae) extending from the muzzle, and well‑developed auditory pinnae that stand erect. Eyes are fully opened, amber or pink depending on strain, with clear corneas and no signs of immaturity.
Limbs are proportionate, with forepaws possessing five digits and hind paws four digits, each equipped with sharp, retractable claws. Musculature is visibly stronger than in younger pups, supporting more vigorous climbing and burrowing activity.
Sexual characteristics become evident: males may display enlarged testes within the scrotum, while females show the onset of estrous cycles and slightly enlarged nipples.
Overall, a three‑month‑old rat resembles an adult in external appearance, differing mainly in size and subtle maturity of reproductive organs.