Ah, the elusive Hallowsevus costumeus . . .

It’s that time of the year again, when many of us procrastinators, myself included, are scrambling for a last minute all hallows’ eve costume. Sure we could go with the ol’ reliables; the classic sheet over the head ghost costume, the witch costume you wore for the last three years in a row, or the ever popular throw on a pair of furry ears and call yourself a cat. Any one of these costumes would be fine, you’d have a great time out with your friends, and it would be a halloween like any other. But, let’s face it. We are scientists and ‘fine’ isn’t good enough, we need our costume to be great, fantastic, a stand-out. Coming up with said fantastic costume idea is rarely easy, though you would be surprised at the inspiration mother nature can provide.

Many species of crabs, insects and birds have been known to decorate themselves, creating a costume of sorts, with various environmental debris, and even other animals! My favourite decorating animals are crabs I have nicknamed Hallowsevus costumeus. Though they are actually called decorator crabs, I think my name is much more descriptive considering their advanced skills at wearing anything and everything in their the environment on their backs or legs.  Their purpose for decorating themselves is mostly for camouflage from predators, which is quite opposite to most people’s goal on halloween (unless you are trying to avoid being spotted by an ex at a party), and they are pretty darn good at it.

A drawing of a decorator crab. Credit: http://www.supercoloring.com/pages/crab-3

A drawing of a decorator crab. Credit: http://www.supercoloring.com/pages/crab-3

Decorator crabs have fine hooked hairs called setae on their bodies, which act like velcro for debris or animals to be attached to. When the crab finds something it wants to wear, it simply rubs it against the part of its body it wants it to stick to and voila! There it sticks. Some decorator crabs go a simple route, and hide themselves by holding a piece of kelp or seaweed on their back. Others use sponges, corals or other small invertebrates that they can attach to their backs. Camouflage isn’t always the end goal of self-decoration. Some crabs will opt to carry around noxious animals on their backs as a predatory defense. Now that would be handy, particularly a costume that deters rude people at parties. Actually I would wear that in everyday life.

There is a crab under all that believe it or not. Credit: http://endangeredliving.com/2013/10/31/costumed-animals/

There is a crab under all that believe it or not. Credit: http://endangeredliving.com/2013/10/31/costumed-animals/

Anyways, back to the crabs! I was lucky enough to encounter some decorator crabs this past weekend on a class field trip to Bamfield Marine Sciences Center on Vancouver Island (a wonderful magical science place, that you should visit). We did a dredge of the sea floor and found a teeny tiny decorator crab amongst the sediment and other animals (pic). I was actually quite surprised at how well this little crab blended in, and didn’t know what it was at first. The power of velcro setae decoration!


A tiny decorator crab brought up in the dredge near Bamfield Marine Science Center, on Vancouver Island.

Now, I realize we do not have little hooked hairs on our bodies to stick random items to (though if you do, that’s pretty awe inspiring), but we do have other means of affixing items to our wares. Tape, glue, string, you get the picture, but always attach to clothing, and not your skin. Never glue anything to your skin no matter how awesome it makes the costume look. It’s not worth it, trust me.  So take some random items from around your house and attach them to your back, arms, legs, and head and call yourself a decorator crab this halloween! I would be super impressed if I saw someone with that costume. Or take a less literal approach, and get creative with using items you already have to make a more unmistakable costume, such as the tinfoil in your cupboard to be a futuristic space alien, or use some old feather boas to turn yourself into a fuzzy caterpillar. Everyone has boas laying around their house right? Or Is that just me? But you get the picture. Now hop to it, you only have two days left to make that amazingly creative costume to earn you a pile o’ candy. Mmm, candy. Happy Halloween!

Follow the links below for neat examples of animals decorating themselves.

For the more fashion-aware, fancy dress decorator crabs video:


A cute video for the young ones in your life, Octonauts meet a decorator crab:


Animals that decorate themselves for various reasons:


For info on the Bamfield Marine Sciences Center:


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