The phrase "natural climbers" means creatures or individuals that are naturally skilled at climbing or moving up objects or surfaces with ease. Full definition
Hamsters, gerbils, guinea pigs, rabbits and ferrets are not natural climbers and have a tendency to fall off of shelves. (petbusiness.com)
Hamsters and gerbils are not natural climbers, but rats and mice enjoy climbing, so adding toys like ladders, trees, perches and ropes to their cages will give them the opportunity to exercise this ability. (petbusiness.com)
Rock Climbing Camp Kids are natural climbers and that's why they love this camp! (sportstarsmag.com)