DID YOU KNOW that a rat's teeth continue to grow throughout their lifetime? Teeth usually wear down naturally to a safe and healthy length as the rat grinds them and eats, BUT this isn't always the case. For this reason, the rat's UPPER & LOWER teeth should be checked regularly and trimmed by a veterinary professional as needed. Sometimes teeth that don't wear down properly even need to be extracted. As you can see in the photo, the rat's lower teeth are very long and have grown into the upper jaw which is very painful and can lead to infection, inability to eat, etc. You can easily check the length of your rat's upper and lower teeth by simply opening the rat's mouth and looking inside OR feeling the teeth with your index finger. Routinely giving your rat HARD food "treats" like raw macaroni is helpful to wear teeth down and it's perfectly safe because it's edible unlike popular wood chews. Wood is not a safe chewing alternative because it's NOT edible and can cut the inside of a rat's mouth, and if swallowed, cut the throat, perforate a bowel, etc. It's a good idea to mark your calendar for a weekly teeth check.