The Pincers: To Crush or To Cut?

Crabs and lobsters in the crustacean family are nothing but interesting.  Apart from its delicious, salivating meat, a part of its anatomy has evolved amazingly deemed unnoticed.

I am referring to their claws or pincers.  Even the marine biologist in me has just taken notice recently.  I am not a specialist though so it’s considered and ignorance is negligible.

Scientifically termed as “chelae”, these appendages occur in different shapes, symmetry and function. Let’s have a closer look to a few contingents and discover their uniqueness and beauty, we’re not talking about “brains” here.

# 1:  Giant Lobsters (Homarus americanus)

Just look at these enormous pincers! And have you noticed? Do you see what I see? The pincers are dimorphic, meaning they are not the same.  

Yes, how strange could that be. In this lobster, Homarus americanus, the crusher chela (left), which is slow acting and powerful, is used for crushing the shells of mussels and other preys and the cutter chela (right), which is fast-acting but weaker, is used to capture swimming fish and other prey on the way. Notice also, the crusher claw has round molar-like teeth while the cutter claw has small serrated teeth. Not only the crusher claw symbolizes strength and agility but they also serve to attract females.
Talk about machismo here.  Life of female lobsters must be simple, there is no other reference.




# 2:  Langoustine (Nephrops norvegicus)

Also known as Norway lobster, this is another kind of lobster having long knobbled claws. Unlike other crustaceans, langoustine don't change colour when they are cooked. These guys are delicious too. They also posses dimorphic claws like the giant lobster but this one looks lanky and fragile, I wonder how they are able crush or cut their prey lest they crumple. Which by the way reminds me of Edward Scissorhands.  

Life of Edward Scissorhands.

# 3:   Spanner Crabs (Ranina ranina)

I like the sound of their scientific name. Sweet!

These marine dwellers are found from close inshore to at least 100m, usually buried in sand from where they attack small bottom-dwelling fish. Their long, almost goblet-shaped, bright orange shells (even when uncooked) and spanner-shaped front claws are quite distinctive.

The movable claws are bent inwards resembling the end of an adjustable spanner. Yes, indeed.  But they have symmetrical claws, could be an adaptation since they don’t need much effort to crush, they are opportunistic feeder, meaning “dawat-limpyo” in Cebuano language.



Amusingly, Spanner Crabs move in a forwards-backwards motion, unlike other crabs who move sideways.

This large crab is red in color and stays the same color when cooked.  Very delicious too. 

# 4: Fiddler Crabs (Uca species) 

Photo by: Ryan Macalandag

These guys are my favorite.  Physically, the male and female differ in their claws.  In males, the claws are dimorphic, one claw is huge and swollen that can be 3 or 4 times their body size.  The male has to sacrifice one claw to be the “fiddle” devoted for waving display during courtship and mating and for fighting other males to get the females.  Oh, females are lucky, they have a lot of choices.  For the females, the claws are petite and equal in size.

I remember when I was young, we used to pet them.  We generally call them “agokoy” in Visayan term and the males are called “kampilan” because of its fiddler claw. “ Kampilan” is a single-edged long sword of the Filipino Muslims relatively more of a straight profile, with the blade tapering wider from its base, getting broader and thinner at the point than its base.  This is how they got their name, they look like warrior with sword and shield.

When they all come out of their holes to feed or mate or perhaps a time of play, they form incredible mosaic of colors in the mudflat.  With a small noise or vibration, they quickly hide back to their holes.  That must be a chaos, do they get back to their own chamber or they just randomly get to the nearest hole they could hide into?  Maybe yes, after all, they are neighbors!!!

These guys also exhibit a beautiful mating dance.  Here is an excerpt of the mating dance displayed by these lively and jolly "AGOKOYS" ruled by the action of their fiddler claws.

IT IS A BALMY TROPICAL EVENING, music is in the air.  The dance begins. He makes his move, a sly beckon. He crooks his finger at her and waves enticingly while rapidly bowing his FIDDLE.  She approaches. His beckoning becomes faster. The music intensifies. He flexes his finger like the villain in silent movie. If she likes the tune he plays on his fiddle-shaped major claw and is seduced by his gestures, she enters his dark lair.  Soon she leaves the nuptial chamber, pregnant.  Deep inside her body lies a packet of sperm to be saved for future use.  

She resumes her usual behavior, straining mud through her mouthparts, removing and swallowing the rotting organic material contained therein and spitting out little balls of now pristine sediment that lay strewn about her burrow.  She is hungry, the metabolic need of the tiny lives buried within her demanding nutrition.  Home to this female is the hole in the mud surrounded by these spitballs.

 (Quoted from: The Sensous Seas: Tales form a Marine Biologist, Eugene H. Kaplan)

These are just glimpses of the beautiful evolution and adaptation of marine organisms, wherein their unique environment has shaped their unique beauty and character.