There is also the fact that a male can pull their testicles up inside their body, and is likely to do it if they are scared or startled, such as when roughly picked up or picked up by the tail, as is likely to happen with a pet store employee. If you look closely, you will still notice an extra wrinkle or two of skin that is the empty scrotum, but a casual glance from a pet store employee who doesn't care is likely to miss it.