Creature Feature

Norway Rats

Despite being native to the eastern Siberia/China border and parts of Japan, the so-called 'Norway rat' owes its misleading name to a centuries-old mistake. This misnomer arose when the English naturalist who classified the rat in 1769 mistakenly believed the rat had arrived in the UK on Norwegian ships. Although not true, the name stayed and continues to be used today.

The Norway rat has a long history of travel, both in name and geographically. Norway rats spread west from Asia through human migration, arriving in Europe in the 1500s and the Western Hemisphere in the 1700s. They are a worldwide pest, dominating Europe and most of North America. The only exceptions are polar regions, some islands, and the Canadian province of Alberta. Alberta has worked hard since the first Norway rat was discovered in 1950 to keep itself rat-free, including monitoring a buffer zone within 18 miles (29 km) of its lower eastern border with Saskatchewan and destroying rats whenever they are found.

Management failures are often attributed to neophobia, a rat's tendency to avoid new objects in its environment. However, the real issue is more likely due to treatment measures being placed too far from established rat routes. These routes can be identified by inspecting for rat droppings, rub marks, gnawing, and burrows. Bait stations are convenient because they house either rodenticide baits or snap traps, protecting them from the elements and shielding children and pets from exposure. Rodenticide baits can handle large populations well. Snap traps offer varied and enticing bait options, appealing to wary or finicky rats, and are ideal when it’s preferable to remove rats rather than let them die on site. In many states, a non-lethal bait that reduces fertility in both male and female rats may also be an option, offering a humane and sustainable way to gradually reduce rat populations over time.

Whether through traps, bait, or fertility control, targeting rat behavior is key to managing their populations effectively and minimizing their global impact.