I bought them from a pet store where they told me they were 2 months old. I just weighed and measured them after having them of a full week at home. It seems to me that their weight doesn't match their length or they are younger that I was told. I thought my scale was off but I tested with my phone against the official specs and it's within .5 ounce difference.
Tinkerbell, female, is 17.5 cms(6.9 inches) and weighs 160 grams (5.6 ounces)
Thor, male, is 20 cms(7.9 inches) and weighs 240 grams (8.5 ounces)
Here is a picture of them, Thor is next to a 500ml water bottle.
According to the charts I've seen, these weights are for a 4 week pup, but the lengths are for 8 weeks old. I don't think they are underweight, at least they have been eating well this past week (timothy hay, very little pellets, fresh grass, 1/2 cup of vegetables, a couple of very small slices of fruit to bribe them and gain their trust jeje). They are pretty active, the cage is not so big but it's open during the day and they have the run of the living run and small back patio, so they run around a lot.
I'm new at this so I was hoping you guys could help me determine their age and if they are maybe underweight. Thanks
- Supporter 2004-2019
They may well be younger than the pet store said, but if they are lively, eating eagerly, and and gaining weight steadily, I would not worry about their exact ages. You should weigh them every couple of days at this stage (and at least weekly when they get older) and keep records. But most important: keep them separate!!!
No other animals that can get in, walls are solid and 10 feet high, no opening to the street just to my living room. Only small dogs a couple of houses on this street. I haven't seen any predatory birds here.
At mid day they are always in their cage in the house. They're only in the patio/grass before noon in the shaded areas and they always go in as soon as the shade begins to recede, then we take them out for a couple of hours before sunset before going back in for the night. Been watching them 100% of the time so far, part worried about anything happening to them and part being amused by their curious behaviors and enjoying watching them.
- Supporter in 2019
As for their ages, you can't determine this based on weight or other measurements. They could be under-nourished, and some guinea pigs are naturally smaller than others at the same age.
Since you're new to guinea pigs, I'd also suggest that you check out the GL Care Guide for more information on housing, diet, etc.:
More information on determining guinea pig sex:
Which vet would you recommend as having the MOST experience with guinea pig neutering?
By asking this, you are not dissing any experience they might have, but if they are honest you will hear who they know who has the most. It might be them, it might be someone else. I called about 6 to 8 vets in my town that I had heard were good in general and/or were near where I lived. When I heard the same name over and over again as having the most experience, that's who I went with, and I have not regretted it.
You see, I had at first just asked "Do you have experience with guinea pigs?" and my vet (who I had gone to with our dogs and cats for years) answered yes. But he didn't catch that my male was actually a female and I found out later that his "experience" was once quite a few years ago. By asking who has the most experience that they know of, you are more likely to find a vet with the most experience!