Animals are classified into different classes; one of them is Mammalia (mammals). Mammals are divided into different orders; one of them is Rodentia, also known as rodents or gnawing mammals. Mice, rats, flying lemurs, squirrels, hamsters, gophers, guinea pigs, porcupines, and beavers are examples of rodents. One of the common characteristics of rodents is having upper and lower pairs of incisors that are continuously growing. Most rodents eat seeds, but some of them have a more diverse diet.
How many types of rodents are there?
Rodents are the largest order of mammals and include more than 4500 species (40% of mammals). They may be used as pets, laboratory animals, or sources of food and clothing (fur). Here, we only deal with those rodents that can cause serious health, property, and food damage in the province of British Columbia.
How can rodents be identified?
Correct identification of rodents is very important because they have different control methods.
The presence of droppings is the main and easiest evidence of rodent activity. Hearing noise from void places and attics (chewing and moving), damaged food packaging, etc., are other signs of rodent infestation.
Rodent species in Vancouver
House mice (Mus musculus, Muridae)
The house mouse is small with a hairless tail. The tail length is equal to the length of the body. The nose is pointed, and the ears are large in comparison to the head. House mouse is nocturnal but may be seen during the day, especially when the population is high. It’s able to climb, jump, and swim. Inside buildings, they make nests in protected and void places. Outside, they dig burrows in which they build their nests or live in crevices. House mouse is omnivorous, which means it eats almost everything. When living inside, it reproduces throughout the year, but when outside, reproduction stops during cold weather.
Pregnancy lasts around 20 days and each female produces seven or more litters each year (5-7 young per litter). In lab conditions, house mice can live for about 3 years. Mice droppings are about 6 mm long and can be found wherever they are active. It’s usually considered the first indication of mice activity.
Diverse features like the ability to survive in different habitats (buildings, fields, deserts, croplands) and a high reproduction rate help these creatures thrive almost everywhere.
Brown rat (Rattus norvegicus) and black rat (Rattus rattus)
The brown rat is larger than the black rat, with a blunt nose and small ears in comparison to the head. In the case of brown rats, the combined length of the head and body is longer than the tail. But, black rats have a longer tail compared with the combined length of their head and body. Brown rat droppings are about 19mm long with blunt ends, but black rat droppings are about 13mm long with pointed ends. Black rats have larger ears compared with their heads. Rat females produce more than seven litters each year, with eight to twelve young per litter.
Brown rats prefer to live on ground level and make burrows in the ground around buildings; black rats prefer to live on upper floors, walls, and ceiling areas.