What do 5-month-old rats look like? - briefly
At five months, rats have reached full adult size, typically weighing 250–300 g, with a sleek, fully furred body, prominent ears, and a long, hair‑covered tail proportionate to their length. Their coloration reflects the strain’s genetic pattern, and they exhibit mature musculature and developed whiskers.
What do 5-month-old rats look like? - in detail
A rat that has reached five months is fully mature in size and morphology. Body length, measured from nose to the base of the tail, typically ranges from 18 to 22 cm (7–8.5 in). The tail adds another 15–20 cm (6–8 in), giving a total length of approximately 33–42 cm (13–16.5 in). Adult weight falls between 250 and 350 g (0.55–0.77 lb), with males generally heavier than females by about 10–20 g.
Fur is dense and glossy, covering the entire body except for the whisker pads and foot pads. The dorsal coat often exhibits the strain‑specific coloration: common laboratory strains such as Sprague‑Dawley display a uniform gray‑brown hue, while Long‑Evans rats show a black dorsal stripe with a white ventral surface. The fur on the head and ears may be slightly longer, giving a “ruffed” appearance.
Sexual dimorphism becomes evident at this stage. Males possess a larger anogenital distance, more pronounced musculature in the hindquarters, and a broader, blockier skull. The testes are fully descended and palpable. Females exhibit a slightly slimmer profile and a more tapered abdomen; the estrous cycle can be observed through periodic swelling of the vulvar area.
Skeletal development is complete; the vertebral column is straight, and the limbs display normal articulation without the curvature seen in younger juveniles. The ears are proportionally large, erect, and covered with fine hairs. Eyes are fully pigmented, with a clear cornea and no residual opacity.
Dental characteristics are stable: the incisors are continuously growing, exhibiting a characteristic orange enamel due to iron deposits. The molars are fully erupted and show the typical occlusal pattern of ridges.
Overall, a five‑month‑old rat presents as a robust, fully grown rodent with definitive adult proportions, strain‑specific coat coloration, and clear sexual differences.