What makes rats a pest
Rats carry fleas and mites on their bodies which also transmit diseases to humans through their bites. Moreover, rats have been known to bite humans. To prevent their front teeth (called incisors) from growing too long, rats need to gnaw constantly. This gnawing habit destroys household items. Buildings have gone up in flames because rats have gnawed through the insulation around electrical wires.
Rats and mice are social animals and prefer to live in nests. Outdoors, their nests can be found in garbage dumps, in the ground, in drains and other areas where food and shelter are nearby. Indoors, they hide in wall and floor voids, roof voids and furniture. Although rats cannot see well, they have very sharp senses of smell, hearing and touch. They eat all types of food and search for food during the night. They are good climbers and jumpers.
About rodents in general
Rodents are mammals, which are characterised by a single pair of continuously growing incisors (front teeth). They are the most diversified mammalian order and live in various terrestrial habitats, including human-made environments. Rats and mice are rodents that can transmit various diseases to humans such as leptospirosis, murine typhus, rat bite fever, plague, etc. They are highly ferocious, adaptable to changing environments, and have a high reproductive rate. However, they have poor visual acuity and colour blind, relying on their extremely strong senses of hearing, touch, taste, and smell. They are active climbers, excellent jumpers, and swimmers.