What do one-year-old rats look like? - briefly
A one‑year‑old rat is fully mature, weighing about 250–300 g, with a sleek, short coat that is typically brown, gray, or black, and a tail roughly equal to its body length. Its ears are prominent, eyes pinkish‑red, and the body lacks juvenile characteristics such as a rounded belly.
What do one-year-old rats look like? - in detail
One‑year‑old rats have reached full adult size. Body length (head‑to‑base) typically measures 20–25 cm, while the tail adds another 18–22 cm. Average mass ranges from 250 g to 350 g for males and 200 g to 300 g for females, reflecting modest sexual dimorphism.
Fur is dense and glossy. Common laboratory strains exhibit a uniform coat color—often albino (white with pink eyes) or pigmented (brown, black, or agouti). Wild‑type specimens display a dorsal stripe and a lighter ventral surface. Whiskers (vibrissae) are long, stiff, and extend several centimeters from the snout, providing tactile feedback.
Head features include a rounded skull, prominent incisors that continuously grow, and eyes that remain bright and unclouded. Ear pinnae are large relative to head size, thinly furred, and highly vascularized, aiding thermoregulation. The skin underneath the fur is thin, pinkish in albinos and pigmented in darker strains.
Reproductive organs are fully developed. Males possess prominent testes within a scrotum and a noticeable anogenital distance. Females have well‑formed mammary glands and a visible vaginal opening. Both sexes exhibit a smooth, hair‑free genital area.
Key physical characteristics can be summarized:
- Size: 20–25 cm body, 18–22 cm tail
- Weight: 250–350 g (male), 200–300 g (female)
- Fur: dense, color varies by strain; dorsal stripe in wild types
- Facial features: long whiskers, continuously growing incisors, clear eyes
- Ears: large, thinly furred, highly vascularized
- Genitalia: fully mature, sexually dimorphic
These attributes distinguish a rat at twelve months from younger juveniles, which are smaller, lighter, and possess less developed secondary sexual characteristics.