In the UK compost bins have open bases. Many local councils have been subsidising the purchase of these bins. They are fine for grass cuttings and leaf mulch etc. The big drawback to putting food waste in compost bins is that it attracts rats from far and wide. The gardens on our side of the road were overrun with rats until we all stopped composting food waste.
Not totally unconnected, in the UK 'hardwood decking' has become popular in gardens. Rats just love living under decking.
We don't have bears in the UK anymore, though they would make bigger targets than rats.