Last year, when it rained steadily for a few days, I had lots of snails on, under, and around my patio wall, trying not to drown. This year, when it rained in January, there were no snails.
I commented on it to my roommate and wondered aloud if perhaps the gardeners were using some sort of fertilizer or herbicide that had killed them off. I missed my snails!
When I mentioned the absence of snails to my sister she suggested that a more likely cause of the missing snails is the presence of opossums, known locally as possums. I have never seen a possum but that is probably because they are nocturnal and I am not.
When I looked up the topic of possums on Wikipedia I discovered that they are not native to the Pacific coast but were introduced during the Great Depression, probably as a source of food. I suspect that possums were welcomed into my condo complex by the people who like to leave food out for feral cats. They may not realize that in addition to feeding stray felines they are also feeding cat-sized marsupials. Or, they may not care.
The possums in North America play an important role in pest control and sanitation. They eat almost anything, including trash and roadkill, and because they need a lot of calcium they even eat the bones of the creatures they find. In order to accomplish this, they have fifty teeth!
Among the many things they eat are snails, and so it would make sense to conclude that they are the reason that my patio snails disappeared. Today, however, I saw three snails! It has been raining all day and these three snails surfaced. I was pleased to see that some have survived, but I hope the possums didn’t see them. I’d like to keep a few around as my own garden pets.