How do different rat species look? - briefly
The common brown rat (Rattus norvegicus) is robust, gray‑brown with a blunt snout and short tail, whereas the black rat (Rattus rattus) is slimmer, reddish‑brown, with a longer, hairless tail and larger ears. Other species, such as the desert kangaroo rat (Dipodomys deserti) and the Polynesian rat (Rattus exulans), exhibit pale sandy fur with elongated hind limbs or a uniformly dark coat, respectively.
How do different rat species look? - in detail
Rattus norvegicus, commonly called the brown rat, measures 20–25 cm in body length with a tail of comparable length. The coat ranges from dark brown to almost black, with a lighter belly. The skull is robust, featuring a blunt snout and relatively short ears that sit low on the head. Hind limbs are strong, supporting a weight of 250–500 g.
Rattus rattus, known as the black rat, is slimmer and slightly smaller, 15–20 cm body length and a tail that exceeds body length by 2–3 cm. Fur is glossy black to dark brown, often with a distinct white or pale patch on the belly. Ears are larger and more pointed, positioned higher on the skull. The species typically weighs 150–250 g.
Rattus tanezumi, the Asian house rat, resembles the brown rat but displays a more reddish‑brown dorsal coat and a paler ventral side. Body length reaches 18–22 cm; the tail is proportionally shorter, about 90 % of body length. Ears are medium‑sized, and the whiskers are notably long, extending beyond the snout.
Rattus exulans, the Polynesian rat, is the smallest of the common rats, with a body length of 12–15 cm and a tail slightly longer than the body. The dorsal fur is uniformly brown to gray, while the ventral side is lighter. Ears are relatively large for its size, and the skull is narrow with a pointed snout. Adult weight ranges from 40–80 g.
Rattus argentiventer, the silver‑backed rat, exhibits a distinctive silvery‑gray dorsal stripe that runs from the shoulders to the mid‑back. Overall body length is 18–22 cm, tail length roughly equal to the body. The coat is dense, with a gray‑brown ventral area. Ears are moderate, and the species possesses a robust tail covered in sparse hair.
Key visual traits across species include:
- Fur coloration: ranging from deep black, brown, reddish‑brown, to silvery‑gray.
- Body proportion: tail length relative to body (equal, longer, or slightly shorter).
- Ear placement and size: low and small in brown rats, higher and larger in black rats.
- Snout shape: blunt in larger species, pointed in smaller ones.
- Size and weight: from under 50 g in the smallest species to over 500 g in the largest.
These morphological differences enable identification of individual rat species in field observations and laboratory settings.