When wandering the beaches this summer , have more to say about the shells you find than why you canhear the ocean in them . Marine biologist Helen Scales’sSpirals in metre : The Secret Life and Curious Afterlife of Seashellsis jam full of interesting fact about seashell and the animal that create them . Here are just a few you may utilise to wow fellow sunbathers this summertime .
1. MOLLUSKS MAKE ONLY ONE SHELL.
Mollusks usecalcium carbonateandproteins , secreted from their mantles , to build their shell . As a mollusc grows , so does its exoskeleton . “ They are among the few animals on the major planet that cheat around carrying with them the same torso armour they had as babies ; the pointy bakshish or inmost whorl is the shellfish ’s jejune shell , ” Scales writes . “ Day by Clarence Day , the shellfish shell slow expand , make room for the soft brute grow at bottom . ”
2. MOST SHELLS OPEN TO THE RIGHT.
Although there are some coinage with shells that are always sinistral , or leave hatchway , nine out of 10 carapace are dextral , mean they open up to the right . Because of their rarity , “ shell collectors go gaga ” for sinistral specimens , Scales say , “ so much so that over the year clandestine trades have prosper in phoney lefties . ”
Though shell collectors might screw them , there are dire consequences to being a sinistral animal : conjugation with dextral mollusks is pretty much impossible . To see what bechance when left-handed pitcher and righties adjudicate to mate , investigator placed pairs of left- and right - spread Roman snail in tank . “ No matter how much the remaining - right spouse are feel in the mood , ” Scales writes , “ the slurp of a sister escargot ’s foot never issues from matte up stall . ”
3. SHAPE MATTERS.
Seashells can be unpatterned and liquid ( think clamshell ) or come adorned with spike and ridges and extrusion . Both SHAPE serve a purpose . luxuriant shells total from the tropics , where depredation is boisterous . Geerat Vermeij , prof of paleoecology at UC Davis and source ofA Natural History of Shells , believes that mollusks in the tropics evolved these ornaments to Aaron Montgomery Ward of predators — a much better option than make a with child , duncical carapace , which will keep marauder at bay but is also a pain to make and hale around . He also think that “ the pleats and corrugation on many tropical shell are a cost - effective way of produce a solid body armor that ’s difficult to bankrupt into while keep the free weight down , ” Scales writes . " Thickening and flare out out the aperature of seashells is another agency of dissuade predators . ”
Sleeker mollusks , meanwhile , can use their streamlined shape to move without spying and to get away quickly . A shell ’s shape can also keep the mollusk from go down in sand and clay , or to keep them anchor in it .
4. THE PATTERNS ON SHELLS AREN’T RANDOM.
late research suggests that the elaborate people of color and patterns on shell are , Scales compose , “ not frivolous playthings but important adjustment marking for scale - fashioning that have been subject to the forces of rude selection , and have evolved over time . ” In other word , mollusks might use the pattern to project out where to put their mantle to continue pretend their shells . scientist still are n’t sure what form of pigments the mollusks are using .
5. THE OLDEST KNOWN HERMIT CRAB USED AN AMMONITE SHELL.
There are intimately 1000 species of hermit crab survive today , which rely on old seashell from dead mollusks to protect their gentle venter . ( Interestingly , according to Scales , hermit crabs never kill the current occupants of the carapace ; they wait until the mollusk has died , and get other animate being do the eating , before they take over . ) The oldest known hermit crab fossil was discovered in 2002 , in the Yorkshire , England village of Steepton . Paleontologist Rene Fraaije spotted the Cancer in the shield , which , Scales writes , belong to an ammonite , “ an extinct cephalopod mollusk that swam through far more ancient seas , in the Lower Cretaceous around 130 million age ago . After it buy the farm it sink down to the seabed where a crab scuttled past tense , break up it up and climbed in spite of appearance . ” It ’s the only one receive in an ammonite so far .
6. NO TWO ARGONAUT SHELLS ARE THE SAME.
For a longsighted meter , scientists believe that Argonaut steal their thin , iridescent case from other animals . Jeanne Power , whoinvented the aquariumin 1832 so she could study argonauts , discovered that the beast are tolerate without shell and , when they reach about the size of a pinky nail , begin to make their shells . But unlike other mollusks , which release their shells with their mantles , female argonauts use glands in two of their arms to make , and repair , their shells . ( virile argonauts do n’t make shells . ) Because of all that repair work , no two argonaut shells are the same .
Argonauts — the only octopuses that still have a casing — can amount wholly out of their shells , which have ribs and ridge that deoxidize drag as they move through the water supply . They use their suckers to hang on , and they ’ll never completely vacate their shell . If you take its shell away , an argonaut will die .
7. ONE OF THE OLDEST KNOWN SHELL COLLECTIONS WAS FOUND AT POMPEII.
The collection was preserved in the eruption of Mount Vesuvius in 79 advertizement and consisted of “ shells that come from distant seas , sure as shooting as far as the Red Sea , that seem to have been restrain for the mere intellect that they looked fairly , ” Scales writes .
8. THAT SHELL YOU BOUGHT ON VACATION? IT WASN’T COLLECTED ON A BEACH.
“ heap of shells are left behind by mollusks that died of disease , predation , old age , or some other portion , but those ones do n’t stay pristine for long , ” Scales writes . “ luck are that your gleaming shell was take from a living animal ; it was compile and killed and its shell remove and sold into the carapace craft , so that ultimately you could grease one’s palms it . ” No one is trusted how many carapace are traded each year , though it ’s thought that around 5000 specie of shellfish are point . And that swop is very in all likelihood affecting wild population ; in some areas , metal money of shellfish have smaller shell than they did in the past , “ a strong reading that not all is well and the expectant specimens have been use up . ” When corrupt shells , be sure to avoid large mintage like the nautilus ( which take a retentive clip to strive matureness , do n’t have many young , and are already over - hunted)—or do n’t buy at all .
