They are considered pests for some people because these critters invades gardens and homes, for kids (like myself) they are pretty cool bugs that doesnât bite and make a great pet. They can grow from a very small size rolly polly to a big one like 18mm or 0.71 inches. They roll into a ball when they sense danger, which makes them look like pebbles if you donât look closely. They can live up to 2 years in the wild, and only 1.5 in captivity. This one in the picture is about 1.1cm long and 0.5cm wide.