The Hand Up Project,
attempting to meet the new needs of natural life forms.
| The Current Situation
Right now, 30% of all hermit crabs on our shorelines are living in shells that are too small for them. In the springtime, when the animal has its growth spurt, this shortage skyrockets to 60%. The problem is that there currently aren't enough shells left on our beaches for hermit crabs to use. As a result, hermit crabs frequently shelter themselves from predators by living in glass jars and other forms of refuse. Land hermit crabs, whose own bodies provide only thin exoskeletons, must scavenge and appropriate hard-walled shells abandoned by marine gastropods for shelter and protection. The reason for this current housing shortage is generally assumed to be the collection of seashells by humans, bottom fishing and pollution.
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Shelter: A Crabs Perspective
Since hermit crabs actually choose the shells that they inhabit, there is a large body of information concerning shell selection. In controlled situations that offer ample housing, biologists have been able to identify the exact features that crabs find most desirable when they are assessing and selecting dwellings.
Hermit crabs typically prefer to adopt univalve-type shells that are spiral in shape. Once a hermit crab adopts a shell, it will keep it until the shell is outgrown, carrying it continuously as a shield, wherever it goes. This is no easy feat, considering that a properly fitting shell must be larger than the hermit crab that wears it, and will often significantly outweigh the crab itself. In order to carry its home, one of the crab's front claws is completely dedicated to clutching the spool of calcium carbonate at the shell's center.
In shell selection it has been shown that there is a specific volume-to-weight ratio that crabs like. Shells with a high internal volume-to-weight ratio are the most in demand. These more desirable shells facilitate growth by providing the crabs ample space in which to physically expand, while saving locomotive energy by being light
in weight.
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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 this afford the animal badly needed additional forms of shelter, but this project contends that, by utilizing current technology, we may at present be better equipped than nature is in addressing the new needs of this natural
life form.
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The use of new materials and design in manufacturing these dwellings is key. The biodegradable plastic affords the crab an almost ideal house. Being much lighter than calcium carbonate, these new houses don't take as much energy to carry during locomotion. Plastic is also structurally strong while remaining light in weight, which affords large areas of internal space in the new structures. This results is 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.
This project proposes to seek corporate support in the funding of future construction. This would allow for the creation of man made fabricated dwellings, bearing corporate logos, to be placed back into nature for the
animal to use.
Future design by Dr. Hao Lin's Senior Work Group at Rutgers University, New Brunswick, New Jersey, based on feedback from Dr. Alexander Turra's Hermit Crab Research Group at University of Sao Paolo, Sao Paolo, Brazil.