If possible, it would be helpful when reporting a catch to identify which species of rat you've caught. This graphic will show you easy ways to tell the difference between the ship rat and the norway rat.
SHIP RAT Rattus rattus ) - A tree climber is the most commonly found rat in New Zealand and is the smaller of the two European rat species. It has a tail that is longer than its body, and ears that cover the eyes when pressed forward.
Introduced into the North Island about the 1860s and the South Island in the 1890s; spread rapidly. Found in most habitats, and is now the most abundant and widespread rat on mainland New Zealand.
NORWAY RAT Rattus norvegicus - A swimmer Introduced late 18th century, established and common throughout the country by the 1850s. Now common only in wet habitats, urban areas and on some offshore islands.
The Norway rat (Rattus norvegicus) is different from the ship rat in that the tail, which is about 18 cm long, is thick and shorter than the body, which is about 20 cm long, and its ear doesn't reach the eye when pressed forward.
HOUSE MOUSE Mus musculus (field mouse)
Established in the Bay of Islands about 1830, reached South Island after 1852. Now common throughout mainland New Zealand from shoreline to snowline.