**Urban Rodents** refers primarily to the **Norway Rat** (*Rattus norvegicus*), **Roof Rat** (*Rattus rattus*), and **House Mouse** (*Mus musculus*). They are globally recognized as the most severe vertebrate structural and public health pests. The conflict is **disease, destruction, and contamination**: they transmit numerous diseases (e.g., Hantavirus, Salmonellosis, Leptospirosis), contaminate vast quantities of food, and cause catastrophic structural damage by gnawing on electrical wiring, pipes, and building materials.
Taxonomy and Classification
Rodents belong to the Class Mammalia, Order Rodentia. They are characterized by a single pair of continuously growing incisors.
Physical Description
Body lengths range from 8\text{ cm} (Mouse) to 25\text{ cm} (Rat).
- **Appearance (Key ID):** Rats are larger with blunt noses; mice are small with pointed noses.
- **Damage ID (Key):** Gnaw marks (parallel grooves); droppings (feces) of various sizes; greasy rub marks along travel routes; pungent urine odors; nests made of shredded material.
- **Behavior ID:** Neophobic (Rats, especially) or curious (Mice); rapid, continuous reproduction.
- **Conflict:** Structural, Public Health, Economic.
Distribution and Habitat
Cosmopolitan, found in every major city globally. Habitat is hidden, protected, dark environments: burrows (Norway Rat), high rafters and attics (Roof Rat), wall voids, and cluttered areas.
Behavior and Conflict
The conflict arises from their constant gnawing and association with filth.
- **Gnathic Destruction:** They must constantly gnaw to wear down their continuously growing incisor teeth, leading to destruction of utilities and structures.
- **Disease Transmission:** Contamination is direct (bites, contact) and indirect (via fleas, mites, or consumption of contaminated food/water).
Management and Prevention
Management is **Exclusion and Population Reduction**.
- **Rodent-proofing:** Sealing all holes larger than 1/4\text{ in} (mice) or 1/2\text{ in} (rats) with concrete, metal mesh, or heavy-gauge sheet metal.
- Use of snap traps, glue boards, and multi-catch traps; application of anticoagulant or non-anticoagulant rodenticides in tamper-resistant bait stations.
- Eliminating food and water sources and removing harborage (clutter).
Conservation and Research
Research focuses on genetic methods of control (e.g., gene drives), understanding rodent population dynamics in sewer systems, and developing effective resistance management strategies for chemical baits.