How many months does a domestic rat grow? - briefly
Domestic rats attain full adult size in about five to six months. Their rapid development is completed within the first half‑year of life.
How many months does a domestic rat grow? - in detail
Domestic rats reach physical maturity within a relatively short span. Newborn pups weigh about 5–7 g and measure 3–4 cm. By the end of the third week they are weaned, can eat solid food, and typically double their birth weight. Sexual maturity occurs at 5–6 weeks; females may become fertile as early as 8 weeks, while males often require 9–10 weeks to produce viable sperm.
Full adult size—approximately 300–500 g and 20–25 cm body length—is generally attained between four and five months of age. Growth slows markedly after the third month, with weight gains of 10–15 g per week tapering to 5 g per week by the fourth month.
Factors influencing the timeline include:
- Genetics: Larger breeds (e.g., Dumbo, Rex) may require an extra few weeks to reach maximum size.
- Nutrition: High‑quality protein and balanced micronutrients accelerate early weight gain; deficiencies can delay weaning and overall growth.
- Health status: Illness or parasitic load can extend the juvenile phase and reduce final adult weight.
- Sex: Males tend to grow slightly larger and may take a week longer to reach peak mass than females.
Monitoring body weight weekly provides a reliable indicator of developmental progress. When weight stabilizes within the adult range for two consecutive measurements, the rat can be considered fully grown.