Editing Homarus gammarus (section)

==Description==
[[File:Homarus gammarus 01.JPG|thumb|left|On this European lobster, the right claw (on the left side of the image) is the ''crusher'' and the left claw is the ''cutter''.|alt=A blue-coloured lobster face-on: the claws are raised and open. The inside edges of the stocky right claw are covered in rounded protrusions, while the left claw is slightly slimmer and has sharp teeth.]]
''Homarus gammarus'' is a large [[crustacean]], with a body length up to {{convert|60|cm}} and weighing up to {{convert|5|-|6|kg}}, although the lobsters caught in [[lobster trap|lobster pots]] are usually {{convert|23|-|38|cm|0|abbr=on}} long and weigh {{convert|0.7|-|2.2|kg|abbr=on}}.<ref>{{cite web |url=http://www.glaucus.org.uk/Lobster.htm |title=European lobster: notes on the sizes of ''Homarus gammarus'' |publisher=British Marine Life Study Society |access-date=October 14, 2010}}</ref> Like other crustaceans, lobsters have a hard [[exoskeleton]] which they must shed in order to grow, in a process called [[ecdysis]] (molting).<ref name="CEFAS"/> This may occur several times a year for young lobsters, but decreases to once every 1–2 years for larger animals.<ref name="CEFAS"/>

The first pair of [[pereiopod]]s is armed with a large, asymmetrical pair of [[feet]].<ref name="MLW"/> The larger one is the "crusher", and has rounded nodules used for crushing prey; the other is the "cutter", which has sharp inner edges, and is used for holding or tearing the prey.<ref name="CEFAS">{{cite web |title=Store and care of live lobsters |first1=T. W. |last1=Beard |first2=D. |last2=McGregor |work=Laboratory Leaflet Number 66 (Revised) |publisher=[[Centre for Environment, Fisheries and Aquaculture Science]] |location=[[Lowestoft]] |year=2004 |url=http://www.cefas.co.uk/publications/lableaflets/lableaflet66rev.pdf |access-date=September 30, 2010}}</ref> Usually, the left claw is the crusher, and the right is the cutter.<ref>{{cite news |url=http://www.national-aquarium.co.uk/news/3 |title=Orange lobster with two sharp claws is one in a million (or more) |publisher=[[National Marine Aquarium, Plymouth|National Marine Aquarium]] |access-date=September 29, 2010}}</ref>

The [[exoskeleton]] is generally blue above, with spots that coalesce, and yellow below.<ref name="Hayward">{{cite book |editor1=P. J. Hayward |editor2=John Stanley Ryland |year=1995 |title=Handbook of the marine fauna of north-west Europe |publisher=[[Oxford University Press]] |isbn=978-0-19-854055-7 |chapter=Crustaceans (Phylum Crustacea) |author1=P. J. Hayward |author2=M. J. Isaac |author3=P. Makings |author4=J. Mayse |author5=E. Naylor |author6=G. Smaldon |pages=289–461 |chapter-url=https://books.google.com/books?id=sZ8mdRT4jbIC&pg=PA430}}</ref> The red colour associated with lobsters only appears after cooking.<ref name="Davidson">{{cite book |first=Alan |last=Davidson |year=2004 |title=North Atlantic Seafood: A Comprehensive Guide with Recipes |publisher=[[Ten Speed Press]] |isbn=978-1-58008-450-5 |chapter=Lobster (both European and American) |pages=188–189 |chapter-url=https://books.google.com/books?id=hFhjGhkAqZ0C&pg=PA188}}</ref> This occurs because, in life, the red [[pigment]] [[astaxanthin]] is bound to a [[protein complex]], but the complex is broken up by the heat of cooking, releasing the red pigment.<ref>{{cite book |editor=Rudolf Kreuzer |year=2008 |title=Freezing and Irradiation of Fish |publisher=Read Books |isbn=978-1-4437-6734-7 |chapter=Freezing of Shellfish |first=P. |last=Hansen |first2=J. |last2=Aagaard |pages=147–158 |chapter-url=https://books.google.com/books?id=XSywgA8ZVYgC&pg=PA149}}</ref>

The closest relative of ''H.&nbsp;gammarus'' is the [[American lobster]], ''Homarus americanus''. The two species are very similar, and can be crossed artificially, although [[Hybrid (biology)|hybrids]] are unlikely to occur in the wild since their ranges do not overlap.<ref>{{cite news |url=http://www.imr.no/nyhetsarkiv/2010/mai/sensasjonell_hybrid_i_hummarverda/en |title=Unique lobster hybrid |first=Marie |last=Hauge |date=May 2010 |publisher=[[Norwegian Institute of Marine Research]] |access-date=September 30, 2010 |archive-date=October 18, 2019 |archive-url=https://web.archive.org/web/20191018185420/http://www.imr.no/nyhetsarkiv/2010/mai/sensasjonell_hybrid_i_hummarverda/en |url-status=dead }}</ref> The two species can be distinguished by a number of characteristics:<ref name="CEFAS"/>
*The [[rostrum (anatomy)|rostrum]] of ''H.&nbsp;americanus'' bears one or more spines on the underside, which are lacking in ''H.&nbsp;gammarus''.
*The spines on the claws of ''H.&nbsp;americanus'' are red or red-tipped, while those of ''H.&nbsp;gammarus'' are white or white-tipped.
*The underside of the claw of ''H.&nbsp;americanus'' is orange or red, while that of ''H.&nbsp;gammarus'' is creamy white or very pale red.