"Animal" - what is it, definition of the term
The concept designates a multicellular eukaryotic organism that obtains nutrients by ingesting other living matter, lacks rigid cell walls, and typically exhibits specialized tissues, a nervous system, and the capacity for locomotion; such organisms reproduce sexually or asexually, develop through embryonic stages, and are classified within the kingdom that includes diverse species ranging from insects to mammals, exemplified by rodents such as the rat and the mouse.
Detailed information
Rats and mice belong to the order Rodentia, the most diverse group of mammals. Both genera—Rattus and Mus—share a common body plan: a robust skull, continuously growing incisors, and a high reproductive rate.
The brown rat (Rattus norvegicus) typically reaches 20–25 cm in body length, with a tail of similar size. Its weight ranges from 250 to 500 g. The species exhibits omnivorous feeding habits, consuming grains, fruits, insects, and carrion. Adaptations such as strong forelimb muscles and dexterous paws enable efficient gnawing and manipulation of objects.
The common house mouse (Mus musculus) is smaller, averaging 7–10 cm in body length and weighing 15–30 g. Its diet mirrors that of the brown rat but leans more heavily toward seeds and processed human foods. The mouse’s rapid breeding cycle—gestation of about 19 days and litter sizes of 5–8 pups—supports swift population growth under favorable conditions.
Key physiological traits shared by both species include:
- Continuous incisor growth requiring constant wear through gnawing.
- Highly developed olfactory and auditory systems for detecting predators and locating food.
- Flexible social structures: rats form hierarchical colonies, while mice display more fluid groupings with occasional territorial aggression.
Reproductive strategies emphasize early sexual maturity (approximately 6 weeks for rats, 5 weeks for mice) and multiple breeding seasons per year. Both species produce abundant offspring, ensuring resilience against environmental pressures.
Ecologically, these rodents occupy urban, agricultural, and natural habitats worldwide. Their presence influences seed dispersal, soil aeration, and predator–prey dynamics. In laboratory settings, the house mouse serves as a primary model organism for genetics, immunology, and pharmacology, while the brown rat provides valuable data for toxicology and behavioral research.
Control measures focus on habitat modification, exclusion techniques, and targeted rodenticides. Effective management requires integrated approaches that address food sources, shelter availability, and population monitoring.