Spider Crabs: Arachnid Imitators at Sea
Spindly Crustaceans are Deceptively Powerful & Sometimes Large
The Northern Kelp Crab Pugettia producta is one of the closest things to an alien in the Pacific Northwest. A bizarre real life creature, this fantastical looking crustacean is a spider crab that blends in effectively with its highly favored seaweed rich marine habitat.
Growing up to 4 inches in carapace width in the case of males and three inches in females, this spider crab ranges from yellow brown to reddish to greenish in color. With an imposing pinch and little flesh, this species is not popular with humans as a food source. Despite the delicate look of this crab, it is exceptionally wiry and more than capable of fighting back if a threat is perceived. A nasty pinch is a surprise considering the delicate look of this creature! Spider crabs are well named, for they do look like very large spiders in the ocean.
Feeding mostly on plant material in the summer months, this spider crab species catches food in a peculiar way. A spider crab looking to do a "takeaway" meal will attach small seaweed fragments to hooks located a little ways behind its eyes. These are eaten later. In winter, these crabs often seek out animal prey including small shellfish.
The kelp that these crabs seek out is not only food, but shelter. Hungry sea otters and other predators looking to catch these crabs find it much harder to pick a crab out of a kelp bed than open shallow water. While the size of the Northern Kelp Crab is impressive, this is a tiny species compared to the true giants in the spider crab species ranks. Japanese spider crabs Macrocheira kaempferi reach 16 inches in carapace width with a potential total legspan of 12 feet!