How Much Can a Rat Weigh?
WouterRats weigh around 0.2 ounces when they are born, but can easily gain 40 times their initial weight in a year. When fully grown, a young rat will weigh around eight or nine ounces. They start to grow body hair around two days after birth, and open their eyes ten to seventeen days later. Adult rats have a body temperature of 37.5 to 38.8 degrees Celsius, and they have good swimming abilities.
Rats are generally bigger than mice and have long tails that can grow nearly as long as their bodies. Rats come in several different species, including wild and domesticated varieties. Size varies depending on species, but a typical Hoffman’s rat weighs between 3.4 and 8.5 ounces and measures 6.7 to 8.3 inches. In comparison, a cloud rat, which lives in the Philippines, can weigh up to four pounds.
Rats that are underweight have a dehydrated appearance and lack muscle tone. They also tend to look gaunt, but this isn’t always a cause for concern. Some rats simply have an unexpected growth spurt and require an added boost. If you notice your rat underweight or gaunt, you may need to increase its food intake.
Rats are prolific breeders. They can produce as many as five litters a year. Female rats can lay between five and twelve pups a year. Typically, a female will give birth to one litter every two to three weeks. Their pups will be about two to four inches long and weigh up to eight grams.
