Is snail you find from the backyard the same snail you eat? Does it both taste similar?

[Johnny]

I ate snail but it was real tiny but then I see another snail like the one you can see in the backyard...not in my mine's but I saw it in someone else's....I was wondering if you eat the snail found in backyards?
actually I did see snail in the backyard of the house I used to live in......

why is the snail I ate small but the one in the backyard is huge?