Wednesday, June 23, 2010

Hermit Crab

I’d like to cast a more charismatic creature in the role...



...however, the hermit crab might be my personal totemic animal.

Hmmm…I'm OK with that. Might as well be!

I have a reason for contemplating the humble hermit crab – I read a story last week about hermit crabs lining up on the beach, according to size. Then, in sequence, each crab abandons its old shell and moves into the next larger one.

At first, I thought this could be a fantastic metaphor, but now I’ve learned that the ritual really happens. The biologists tell us that shell exchange can occur in various ways.


Caribbean Hermit Crab

From a recent scientific paper, Social context of shell acquisition in Coenobita clypeatus hermit crabs, by Randi D. Rotjana,b, Jeffrey R. Chabotc and Sara M. Lewis:

Examining shell behavior in a social context is critical to understanding hermit crab behavior in the wild. Synchronous vacancy chains occur after several crabs adjacent to an available vacant shell have queued in decreasing size order; as soon as the largest crab switches into the vacant shell, a rapid series of sequential shell switches takes place.

In asynchronous vacancy chains, in contrast, individual crabs encountering a suitable vacant shell will switch and later their discarded shells will be discovered and occupied by other crabs. Thus, asynchronous vacancy chains do not involve social interactions or queue formation, and sequential shell switches take place over considerably longer time periods. In both cases, vacancy chains are terminated when the last shell discarded is of such low quality (too small or damaged) that all crabs reject it.

[ link http://beheco.oxfordjournals.org/cgi/content/full/21/3/639 ]

But, how about a visionary effort to intervene in the ritual of hermit crabs by providing plastic shells for the hermit crabs? Elizabeth Demaray wrote about this in Futures Spring 2004, The Hand Up Project: Attempting to Meet the New Needs of Natural Life-Forms.

A strong case for synthetic housing:

The Hand Up Project
Based on what we know about the new needs of these animals in their current environment, the Hand Up Project proposes to manufacture alternative forms of housing, specifically designed for use by land hermit crabs, out of plastic. This solution offers multiple benefits. Not only will the project afford the animal badly needed additional forms of shelter, but we also contend that, by utilizing current technology, we may now be better equipped to meet the needs of this life-form than nature ever has.


Hermit Housing

The use of plastic in manufacturing these new homes is key. This material affords the crab an almost ideal dwelling. Being much lighter than calcium carbonate, these new houses do not take as much energy to carry during locomotion. Plastic is also structurally strong, which affords large areas of internal space in the new structures. This results in the greater internal volume-to-weight ratio that the crab prefers. Of additional benefit is the longevity of this material coupled with the way these crabs recycle and share their shelters. Due to the fact that plastic is non-biodegradable, these new forms may potentially outlast the life-span of the crab itself, thereby assuring many generations access to additional hand-me-down housing.

Synthetic Shell Prototypes

We acknowledge that such trans-species caregiving may in fact be a form of control. In recognition of this paradox, the new structures are aesthetically based on the architecture of Giuseppe Terragni, an Italian Fascist active in the 1930s. Physically, the design of the new forms has been tailored to the animal's needs. The structures are offered for various body sizes. The shell spiral in the middle has been eliminated, reducing the overall weight of each house and increasing its internal volume. Instead of this central core, the new design offers an internal flange attached to the front opening for the crab to clutch with its holding claw.

Shelter while foraging has also been considered. Similar to the hood-like structure found in a traditional shell, the new form offers an overhang for additional protection in situations where the body must be extended outside the dwelling. Color can also be adapted to the needs of the animal. The prototype houses are tinted beige, which affords the wearer maximum camouflage on many of the beaches in North America. The color can, however, be visually matched to a specific population's native environment for optimal protection.
[ link http://www.cabinetmagazine.org/issues/13/demaray.php ]

Yes, despite my admiration for their trans-species caregiving, I do find something faintly disturbing about the Hand Up Project. Free-market enterprise will jump on this like a duck on a junebug: beer logos (or worse) on their plastic shells, the hermits crabs will become tiny mobile billboards.

Consider the possibilities.

It’s just not right.


Sirens, Scylla and Charybdis, 17th century etching, Theodor van Thulden (1606 - 1669)
Fine Arts Museums of San Francisco

You can find all sorts of stories about hermit crabs. Some people in Thailand reported that the hermit crabs had retreated to the safety of higher ground well in advance of the 2004 tsunami.

In The Odyssey, Homer tells of Scylla, a monster that devours passing sailors:

...they writhed gasping as Scylla swung them up her cliff and there at her cavern's mouth she bolted them down raw—screaming out, flinging their arms toward me, lost in that mortal struggle...

That same Scylla, of Scylla and Charybdis fame, was known as the goddess of hermit crabs.

4 comments:

DianeD said...

Congratulations on another very interesting blog post. Since it's Friday I thought I should thank you again for your hard work. I get sick of the news, politics, and other junk available to me on this amazing media machine. However, the real reason is to reveal that in my husband's opinion I have a Hamster totem, 'cause my favorite thing in all the world is to cuddle. I just think that is so funny. Have you ever seen hamsters sleeping? They lay on, around and under each other in such a tangled mess you can't figure out who is who. You had said you grew up in Albemarle. Have you been to Town Creek Indian Mound? Fantastic place. Have you done a post on it? If so, I'd like to read it. And the Uwharrie Mtns are so mysterious and weird. Eroded volcanos, yet they still look like volcanos. Thanks again for your valuable blog.

GULAHIYI said...

Well, thank you! I used to have hamsters and just remember that one was named "Ham." (Very imaginative name!)

I try to get to Town Creek any time I'm near there - what a great place. I've been thinking about those turtles that sun themselves on the tree limbs overhanging the creek...saw a bunch the last time I was there. My parents helped with the excavations back in the 1930s and I was there when they dedicated the Park, so I might be a little biased on that account, too. Any North Carolinian who hasn't been there has missed out on an important heritage site.

Anonymous said...

Saw a turtle in my enclosed back yard. This turtle tried hard to get under the gate. The animal totem for turtle tells me to get back into my shell and wait for a safer time to resurface. So, I shall retreat, reframe and resurface when the time is right. There is way too much chaos and confusion going on.

Not a hare.

DianeD said...

We had Sammy and Hector, named after 2 boys my sisters and I had crushes on in elementary school. We went away to the beach on vacation one year, but before we left, we built an elaborate play ground for them on the carport. We had stacked up blocks, books, boxes, and whatever else we could find to create this complicated barrier within which they had plenty of room to run around in and play. Sadly, when we returned home, they were gone! Some cat probably got them but we liked to imagine they were living an adventurous life in the big, wild world.

How cool your parents helped with Town Creek. I had never even heard of it until my sister-in-law Brenda, who grew up in Matthews, turned us on to it. I don't know if this is still true, but you can go through the palisade into the temple area at night, when nobody else is around. Our favorite time there was on a very clear summer night, with a full moon. Such peace. A very peaceful place. Haven't been back in about 5 years. Great museum and artifact collection. Would love to drink some black beer and hang-out with the spirits again. Good weekend to you!