That's an excellent question, and one that anyone who has had their garbage scattered by a determined raccoon or bear has asked. The short answer is: some are, but many standard bins are not. Truly animal-proof lids are a specific design feature.
Standard flip-lids on most basic outdoor bins are not animal-proof. Raccoons, with their dexterous paws, can easily pry them open. Bears can simply smash them. Animal-proof lids, however, incorporate several key features. Look for locking mechanisms—these can be simple latches, lockable tabs, or even combination locks that prevent the lid from being lifted without human intervention. The material is also crucial. While plastic is common, animal-resistant bins often use heavy-duty, reinforced plastic or even metal that can withstand chewing and prying.
Another effective design is the clamp-on lid, which requires significant downward pressure to seal, something most animals cannot replicate. For areas with serious wildlife like bears, certified "bear-proof" bins are tested to ensure they can resist a sustained attack.
So, when shopping, don't just look for a "tight-fitting" lid. Actively search for bins advertised as "animal-resistant," "raccoon-proof," or "bear-proof" and check for robust locking latches and durable construction. It's the best way to keep your trash secure and wildlife safe.