in the United States. Established in 1903, under the presidency of Her Majestyâs Minister at Washington, D.C., W.A.F. Baron Gevers, the chamber has promoted commerce between the Netherlands and the U.S. for more than a century.
Complete Physical Maturity: Mice are not done growing until they are between 3 and 5 months of age, depending on the line. Mice should NEVER be bred until they are at least 12 weeks age. If you don't know the line really well, wait until at least 12 weeks, if not longer.wild mice live longer.. around 5 years in captivity, though only around 6 months in the wild due to predators and environmental factors). Maturity: 4 - 8 weeks of age, varying from line to line and mouse to mouse.
Growth. Guinea pigs grow very rapidly, and will double in size to around 15-20 cm (6-8 inches) after just 8 weeks. After this point their growth will slow somewhat, but they will still get significantly larger in a fairly short period of time, reaching around 20-25 cm (8-10 inches) after 16 weeks.t birth, a guinea pig will generally measure around 8-10 cm (3-4 inches). You should expect some natural variation in size between the animals in a litter, with some bigger than others. The number of pups in the litter also has an effect on how big each baby is-a larger litter will tend to produce smaller offspring.