That's a great and very practical question! Dealing with scavengers like raccoons, bears, or even clever crows can be incredibly frustrating. From my experience and research, the depth of the bin itself is less critical than the overall security of the design. However, depth plays a supporting role.
A bin should generally be deep enough to accommodate a secure, locking lid mechanism without being top-heavy. More importantly, the focus should be on features that *complement* a good depth:
1. Lid is King: The lid must lock or latch securely. Simple flip lids won't work. Look for bins with sturdy latches that animals can't pry open with their paws or snouts. Some have lockable bars or clips.
2. Material Matters: Use a rigid, hard-sided bin (heavy-duty plastic or metal). Avoid bags or flimsy cans that can be easily torn or knocked over.
3. Anchoring is Key: A deep bin is useless if a bear can knock it over. Use bungee cords, a strap system, or even secure it to a post or wall. This prevents animals from rolling it away to break it open.
4. Size & Capacity: A standard 32- to 44-gallon bin is often sufficient if it has the features above. For areas with large bears, specialized bear-proof containers (often 50+ gallons) are designed with complex latching systems.
So, to directly answer your question: There's no single magic depth measurement. Aim for a bin that is deep and sturdy enough to be equipped with a locking, animal-proof lid and that can be securely anchored. Preventing scavenging is about creating a system of deterrents—a deep, heavy container with a locked lid that's fastened in place is your best bet. Start by investing in a quality bin built specifically to be wildlife-resistant.