Announcements, Outdoors, Science

Invasion of the Giant Slug!

Late in the evening on July 26, a giant slug as long as a fireweed leaf and stout as a spruce cone mysteriously appeared cruising on the sidewalk of the 400 block of Third Avenue. The alert discoverer, Deb Kurtz, ran home, called me, came back with a container, and scooped it up. None others were seen.

Wow! I have never seen such a huge slug in Alaska! At 5” long, it positively dwarfs our common Field Slug. This distinctive khaki-green slug has black spots and streaks down its back and sides, hence the common name, and a ridge or keel on the back.

I took it home and put it in a mossy terrarium for further observation and research.

Limax maximum literally means “biggest slug”, and it is among the largest keeled slugs though not the largest. This one measured about 5”; adults range from 4 to 8” long, so this one could grow even larger!

It is native to Europe and Mediterranean countries of Africa, but is now widely distributed around the world. I found reports of it in SE Alaska and possibly Kodiak, but no farther. It may be a new record for the Kenai Peninsula.

What about our gardens and ornamentals? The Leopard Slug is omnivorous, known to eat other slugs (yay!), dead plants and mushrooms. However, it is also known to eat young crops and is thus listed as a major agricultural pest in the US from Florida to Oregon. (Boo!)

As an experiment, I put two much, much smaller Field Slugs (Deroceras reticulatum), also native to Europe, in the terrarium. The Leopard Slug did not seem to show any interest, at least while I watched. As they are nocturnal, it’s hard to observe.

Check out this video clip showing the beautiful and complex mating of two Leopard Slugs from BBC “Life in the Underground” hosted by David Attenborough

There are several YouTube videos detailing how to keep this impressive mollusk as a pet. Apparently they like cat food.

Even though this is an absolutely astonishing animal, it is not native to Alaska and should not be allowed to roam around. If you find one of these and want to humanely kill it, put it in a container and freeze it before throwing it in the trash.

The next time you go for a walk on a cool, rainy evening, keep an eye out for the giant Leopard Slug exploring Seward. Wow!


Carol Griswold





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