Lobster claws - what for?

[Marineboy]

A lobster has two heavy powerful claws, one "serrated" and one "heavy and blunt"

Just out of interest, what function/s do you think a lobster's different claws play? Obviously used in defence, but why the difference in shape and what use is each put to?

[Kayleigh]

I think they are a tool as they hold their food and use them for defence..
Maybe the serrated one allows a better grip.
I know they taste nice whatever they are used for..

[Littlesparrow]

Would there be a bit of territorial claw waving to keep other lobsters at a distance,sort of my claws bigger than your claw get off my land.

[King Edward]

Read this: Asymmetry in Lobster Claws (only first page available free unfortunately).Apparently the thick, blunt claw closes slowly but powerfully and is used for crushing (e.g. bivalve molluscs for food), while the sharp claw closes very fast and is used for cutting.

[Littlesparrow]

Are I must have been thinking of Fiddler crabs.

[Marineboy]

Ahhhh, yes....and no.
I studied a lobster for four years, and yes the big blunt claw is most definately used for crushing. A snail or a bivalve would be carefully orientated, and once in position would be easily crushed.
The other claw though, the one that all the books and all the presenters say is used for cutting, is not used for cutting. Never once, in four years, irrespective of the size of food offered did I see any hint that it was being used for this purpose.

So what else is it doing with it?

It is a trap - a hair triggered trap to snap shut at the slightest touch. On numerous occassions I would watch an unwary creature stray too close to the lobster. A prawn, a shrimp or a blenny would be safe from harm provided it did not touch the hairs lining the inside edges of the serrated claw, held wide open. As soon as it did, the claw would snap shut with such force and speed that you could hear it from right across the other side of the room and know that another prawn had just gone. The edge on this claw is finely serrated and sharp enough to cause immediate damage to anything triggering it.
So despite what the books say, what the natural history presenters say, it is not used for cutting - it is a trap - a finely set hair triggered trap.

Another fact that you don't see in the books is one concerning the intelligence to methodically and carefully bury uneaten food, and to periodically return to it.

[Billabong Karen]

Goodness Marineboy - did you have one as a PET??? Please tell me you rescued it from a restaurant aquarium...

[STYRBJORN]

I have read that they use the click sound to warn rivals off.

Ric

[Marineboy]

Although I regularly see lobsters during dives I don't take any home for the pot. This was one I bought from a commercial fisherman in Mousehole in Cornwall. I had it in a large tank in the living room, with sea water cooled using a beer cooler. Favourite food - squid.
It had been destined for a pot of boiling water, but after several molts it started getting too big and I had to let it go, so I took it to Brixham in Devon. Much to the amusement of holiday makers I marched down a busy beach at the breakwater in full scuba gear with a big lobster in a clear plastic bag, acclimatised it very slowly amidst comments of a culinary nature, and took it for a dive. Four years after saving it from a pot of boiling water, it was great to find it a suitably deep crevice to let it go.

[Billabong Karen]

What a WONDERFUL story!!! I have been diving in Oman, but never in UK waters. Must start another thread asking for advice as to the best dive sites in the UK...

While in Oman, I did a night dive a couple of months ago, and saw a HUGE lobster under a cliff hang... Really impressive, you dont tend to see them during the day. I dont think I'll ever be able to eat lobsters again now. Or tuna. Or cuttlefish. Once you've swum with them, you feel differently about eating them