How Much Do Rats Weight?
WouterRats can vary in their weight from a lean, slim body to an obese one. The best way to judge a rat’s weight is to touch it and feel the different body parts. A rat that has good muscle tone will feel solid to the touch. While a rat that is too lean will look like it’s floating, this is a sign of dehydration and old age. Adding protein and other nutrients to your rat’s diet will help him gain weight.
Rats are born with an average weight of about 0.15 oz and increase in weight by about 40 times their original weight by the time they reach 100 days. In this period, a young rat will weigh eight to ten ounces. They begin to get body hair on two to three days after birth, open their eyes at seven to eight days, and grow bigger and more active.
Rats undergo two stages of their development, a growth phase and a maintenance phase. During the growth phase, the animals’ weights should be analyzed every two weeks. Then, a three-week moving average is taken to calculate the weight. This way, the researchers can estimate the age of the animals and use that information to make improvements in animal studies.
Rats can weigh anywhere from 0.7 to one to four pounds as adults. During their first few months of life, the average house rat weighs about five ounces (150 grams). However, if a rat falls ill, it can lose weight quickly. If you notice a loss of more than 50 grams in one day, you should take it to a vet.
