Melissa Cameron from Liphatech gives a summary of the behaviours and characteristics of the Norway rat.
The Norway rat is known by many names – sewer rat, brown rat, street rat and common rat but all are Rattus norvegicus. These rats will only live for about nine months in the wild due to predators such as dogs, cats, snakes and foxes, but can live in a lab for approximately three years. The colour of their coats will depend on the environment so you can see colour variations from grey, beige and brown.
Thought to have originated in northern China, this rodent has now spread to all continents except Antarctica, and is the dominant rat in Europe and much of North America. This makes it the most successful mammal on the planet after humans as far as spreading across the earth is concerned.
Norway rats have acute hearing and are sensitive to ultrasound. They possess a very highly developed sense of smell and their average heart rate is 300 to 400 beats per minute, with a respiratory rate of around 100 breaths per minute. These rats are very good swimmers, both on the surface and underwater, and will excavate extensive burrow systems for their colonies.
The Norway Rat is a true omnivore and will eat almost anything, but tends to prefer a high protein diet of meat, fish and cereal grains.
Rats are capable of producing ultrasonic noises and may also emit short, high frequency, ultrasonic, socially induced sounds during play or mating. The vocalisation, described as a distinct ‘chirping’, has been likened to laughter, and is in reaction to something rewarding.
Rats create a social hierarchy, and each rat has its own place in the pack with one rat being dominant over all the colony. Groups of rats tend to play fight involving any combination of jumping, chasing, tumbling, and ‘boxing’. If living space becomes limited, rats may turn to aggressive behaviour, which will cause the death of some animals, reducing the burden over the living space.
Melissa Cameron, National Technical and Marketing Manager (PCO), Liphatech