I found this three-level limpet world adrift in the current, like a planet that had escaped its star.
The larger limpet has smaller limpets on its shell; one of the smaller limpets is host to an even tinier limpet. So, a limpet is attached to a limpet that is attached to yet another limpet--which presumably came loose from a rock (or it came loose from an even larger limpet attached to a rock). The scarcity of hard surfaces in the intertidal zone accounts for this multilevel limpet world.
Amid fierce competition for space and food at the ocean's edge, the limpet, along with its molluscan relatives, gains advantage with a stunningly effective feeding structure.
To feed, sea snails, chitons, and limpets use a radula--a device unique to mollusks. I've read descriptions of a radula as similar to a chainsaw, a toothed tongue, a tongue covered in tiny teeth, a ribbon with file-like teeth, and so on. The radula teeth of limpets must be extraordinarily strong to withstand the punishing grinding that occurs when the creatures scrape algae from rock.
A recent study revealed that limpet radula teeth are made of the strongest biological material ever tested. Who would have thought that the little limpets so common on the coast make a material stronger than spider silk, better than Kevlar?
The super-strong adhesive used by barnacles to attach themselves to rocks in pounding surf has been copied in dental surgery. The exceptionally sturdy byssal threads that mussels make to anchor themselves to hard surfaces have been imitated in surgical sutures. And now the stunning strength of limpet teeth has inspired biomimicry. One application of imitating the limpet radula design is strengthening the fuselage of aircraft.
The intertidal zone is a wellspring of wonder for the human imagination. It is also a storehouse of biological design that inspires human technology.
Preserving ecologically intact intertidal zones for future generations makes sense on many levels, from the moral to the practical. Squandering the ocean's bounty for short-term gain is not a sound plan for the betterment of our species.
For our species to survive the inevitable dying of our sun, eventually we must leave this planet. Something as easy to overlook as a limpet tooth can offer clues to the technological advances that will send us to other worlds--perhaps ones with oceans inhabited by creatures as fascinating as limpets.