Things You'll Need
- Tape measure
- Magnifying glass
Instructions
Measure your gerbil's length. If your gerbil measures more than 4 inches in length, it is likely your gerbil is more than eight months old. Younger gerbils are still growing and measure below the 4-inch mark. Measure your gerbil from the top of its head to the base of its tail to get the exact length.
Measure your gerbil's width. If your gerbil measures more than 2 inches wide from side-to-side, it is likely the gerbil is older than eight months.
Look at your gerbil's teeth. Rodent teeth grow continuously, and gerbils file their teeth down by gnawing on food and toys. Longer teeth indicate an older gerbil. Teeth are not always the most accurate way to determine gerbil age, but combined with other clues, the teeth give you a rough age estimate. Look for teeth yellowing in your gerbil. Older gerbils have more yellowed teeth than younger gerbils.
Examine your gerbil's fur. Look for greying areas and lighter-colored fur. Young gerbils have shinier and darker coats than older gerbils.
Check your gerbil's sex to help you determine an age. Gerbils start reproducing around six to eight weeks of age, and genitals are clearly identified as early as three weeks. A male gerbil has a bulge on his backside that is obvious at six weeks old. A female pronounced nipples detectable as early as three weeks old.