Slug Safari

The Columbia River - That's Washington on the other side!

My birthday was two weeks ago so we took a mini-vacation to Portland and the Columbia River Gorge. Holy cats, it's gorgeous up there.

A major highlight of the trip was hiking all over the trails around Horsetail Falls. The countryside there is jewel-like. It's also full of slugs. I of course kept a sharp lookout for invertebrates of all varieties as well as for salamanders, but since it was early February and rather chilly we didn't see too many.

European Black Slug

Eventually I spent more time looking at the view than under rocks so I wasn't expecting it when I came face to face with a slug sitting right in a hole in a tree at eye level. Being black, he was difficult to photograph, but I knew I'd want to identify him later so I took a shot at it. I was hoping he'd turn out to be something rare and exotic.

Well, I was half right. He is exotic. In fact, I think he's European! It seems that the European black slug (Arion ater) is an invasive species that has become established in Washington and Oregon to the point of being a real pest. Despite that fact, my slug is a pretty interesting animal. He (she?) is a hermaphrodite, meaning that each slug can fertilize itself even though mating with another slug is preferred. That helps explain why the species has been able to spread over such a wide area.

Lucky for me that I belong to the look-don't-touch school of animal watching, because my slug is apparently also covered with a foul mucus goo that is very difficult to wash off. If I had picked him up, he would have curled into a ball and rocked side to side in an attempt to get the nasty stuff all over me. This is another reason these slugs do so well outside of their native environment. What predator in their right mind wants to take a mouthful of something so vile? Even so, this mucus used to be used to lubricate the wooden wheels of carts in the slugs' native Sweden, proving that humans really are the most indiscriminate predators of all.

So my slug-finding mission was something of a bust. Guess I'll just have to return in the fall, when the leaves change and the banana slugs are out!