Guinea pig teeth grow constantly, so they need to gnaw in order to keep their teeth from growing too long. Providing your pet with enough toys to gnaw on will help them stay happy and healthy. Guinea pigs like to burrow and tunnel. It’s a natural instinct, so providing opportunity to do that will greatly increase your hamster’s quality of life. PVC pipes, large plastic tubes, and cardboard boxes are all great for crawling, tunneling, and nesting.