Are the small grayish slugs in my garden baby European garden slugs?

Or are they their own species? They're small (often a half an inch), but they do eat a lot.

IPNW gray slug information
It apparently is a European import.

This is a great link, thanks!

Have you tried salt on them?

Here is a link to show I am not crazy Garter snakes a gardener's best friend.
" I really wanted to have more of them because the garter snakes here in western Washington (and likely ones in other areas too) eat a ton of slugs. And this area is famous for its slugs—so I really wanted more garter snakes. "
Back in the 1940's my mother premised to pay a nickel for each snake we brought home.  My system now is to cover my garden beds with dry grass and a tarp. The snakes live in there all winter and eat the slugs and their eggs and at the beginning of summer I see many tiny little snakes through out the garden.   I have very few slugs now.  I do have cabbage moth larva show up but my paper wasps keep them under control.

So So So COOOL!! Thanks for sharing