A ladypig never reveals her age...
Guinea pigs are excellent secret keepers. You probably know if you have a baby or adolescent pig or a senior, but what about all the ages in between? With cats and dogs, it is common for a vet to estimate age by looking at teeth. However, your guinea pig’s teeth are sort of like our fingernails. They grow continuously, essentially replacing themselves over time and ensuring her secret is always safe.
Signs of Aging
A newborn guinea pig may weigh anywhere from 60 to 120 grams and be 3 to 4 inches long, depending on genetics and size of the litter. If your new guinea pig is gaining weight steadily and quickly, they are probably a few weeks to a few months old. In a matter of weeks, the little ones can double in size!
Weight gain becomes more gradual around 5 to 7 months of age. They reach their true skeletal size before one year of age, but may continue to put on weight slowly until they are about 18 months old. After this point in adulthood, it can be nearly impossible to guess their true age until they approach the senior years. While she may never let her true age slip, she may give you a few clues throughout the years.
If you’ve had your guinea pig since she was a baby, you’ve probably noticed changes in her nails. Baby guinea pigs have sharp little nails, but this phase doesn’t last long. Young adult guinea pigs will have straight nails. Seniors often have crooked and thicker nails. Older guinea pigs’ entire front paws may start to turn in. As guinea pigs age, white nails may start to turn yellow. This is one indication that your adult guinea pig may be closer to 4 or 5 than 2 or 3.
As guinea pigs age, they lose muscle tone. That’s where the classic droopy piggy donut lips come from. A loss of muscle may lead to saggy bellies and necks, but bony backs. Weight loss in senior guinea pigs isn’t unusual, but don’t immediately assume it is normal.
This loss of muscle can also affect the jaw, causing the back molars to wear unevenly and cause problems. Weight loss that's accompanied by drooling, a foul odor, an interest in food but inability to eat, dropping pellets instead of chewing them, neglecting to eat hay and tough foods like corn husks, and biting veggies into little pieces but spitting them out signifies tooth problem. A vet visit is definitely in order. Guinea pig tooth problems can be managed by an experienced exotic vet, but may need professional filing every few weeks or months for the rest of her life.
But What's normal?
Guinea pigs have individual differences in regard to weight, shape, and hair length, so looks alone aren’t a reliable way to figure out age. Adults average around 10 to 12 inches long and weigh between 2 and 3 pounds. Just like with us humans, though, a guinea pig that is smaller or larger than these “norms” isn’t necessarily abnormal or unhealthy. Get to know what’s normal for her in terms of weight. Weighing weekly is a great way to identify health problems early.
The average lifespan for a guinea pig is about 5 to 7 years. Many vets consider four-year-old guinea pigs to be approaching their golden years, but there is no hard and fast rule. Just like us, guinea pigs age differently and at different rates.
Signs of aging appear earlier in some guinea pigs, and later in others. A senior guinea pig may lose muscle tone and weight. She may start to develop cataracts or osseous metaplasia in her eyes. She may become less active - fewer popcorns and more naps. Arthritis and other medical concerns may start to pop up, like dental problems.
Is your guinea pig older than you thought? Younger than you thought? Still have no idea? At the end of the day, all that is important is giving her the best care and love possible for the rest of her years – however many that may be.
Additional Reading on Aging Guinea Pigs: