The normal coloration of Homarus americanus is bluish green to brown with red spines due to a mixture of yellow, blue, and red pigments that occur naturally in the shell. [18] [6] On rare occasions these colors are distorted due to genetic mutations or conditions creating a spectacle for those who catch them. In 2012 it was reported that there has been an increase in these "rare" catches due to unclear reasons. Social media influence making reporting and sharing more accessible to a drop in predator populations have been suggested as possible reasons. [19] The lobsters mentioned below thus usually receive media coverage due to their rarity and eye appeal. [20] Color

Currently there is no published genome for the American lobster, although a transcriptome was published in 2016. [72] See also [ edit ] Woods, Madelyn N.; Hong, Theresa J.; Baughman, Donaven; Andrews, Grace; Fields, David M.; Matrai, Patricia A. (2020-08-01). "Accumulation and effects of microplastic fibers in American lobster larvae (Homarus americanus)". Marine Pollution Bulletin. 157: 111280. doi: 10.1016/j.marpolbul.2020.111280. ISSN 0025-326X. PMID 32658664. Homarus americanus commonly reaches 200–610 millimetres (8–24in) long and weighs 0.45–4.08 kilograms (1–9lb) in weight, but has been known to weigh as much as 20kg (44lb), making this the heaviest crustacean in the world. [11] Together with Sagmariasus verreauxi, it is also the longest decapod crustacean in the world; [2] an average adult is about 230mm (9in) long and weighs 680 to 910g (1.5 to 2lb). The longest American lobsters have a body (excluding claws) 64cm (25in) long. [2] According to Guinness World Records, the heaviest crustacean ever recorded was an American lobster caught off Nova Scotia, Canada, weighing 20.1kg (44.4lb). [11] [12] One common way of serving lobster 'tail' (actually the abdomen) is with beef, known as surf and turf. [59] Lobsters have a greenish or brownish organ called the tomalley, which, like the liver and pancreas in a human, filters out toxins from the body. [60] Some diners consider it a delicacy, but others avoid it because they consider it a toxin source; dislike eating innards; or are put off by its texture and appearance, that of a grainy greenish paste. [ citation needed] R-E-S-P-E-C-T! Find out what that means to lobsters. This is what Whole Foods needs to know before they decide to allow the sale of live lobsters again. But while the company stresses "the importance of humane treatment and quality of life for all animals", the real gist of the ban is that Whole Foods wants us to lie to lobsters.B. D. Tall; S. Fall; M. R. Pereira; M. Ramos-Valle; S. K. Curtis; M. H. Kothary; D. M. Chu; S. R. Monday; L. Kornegay; T. Donkar; D. Prince; R. L. Thunberg; K. A. Shangraw; D. E. Hanes; F. M. Khambaty; K. A. Lampel; J. W. Bier; R. C. Bayer (2003). "Characterization of Vibrio fluvialis-like strains implicated in limp lobster disease". Applied and Environmental Microbiology. 69 (12): 7435–7446. Bibcode: 2003ApEnM..69.7435T. doi: 10.1128/AEM.69.12.7435-7446.2003. PMC 309894. PMID 14660396. Several lobsters have been caught that show a different color on the left and right side of the body. According to a researcher at the University of Rhode Island, this split colorization is the result of a genetic condition which causes both sides of the lobster to develop independently. [34] Split-colored lobsters often show sexual characteristics of both sexes, with exceptions. [35] [36] The chance of finding a split-colored lobster is estimated at 1 in 50 million. [21] Holly Anderson (August 13, 2010). "They call him Mr. Blu Genes". oysterriverlobsters.com. Archived from the original on 2011-07-15 . Retrieved 2010-08-13. Lobster Biology – Lobster Council of Canada". Archived from the original on 2016-09-19 . Retrieved 2016-07-06.

Lobsters have two urinary bladders, located on either side of the head. Lobsters use scents to communicate what and where they are, and those scents are in the urine. They project long plumes of urine 1–2 meters (3ft 3in– 6ft 7in) in front of them, and do so when they detect a rival or a potential mate in the area. [16] Thorax [ edit ] Dale Tshudy (2003). "Clawed lobster (Nephropidae) diversity through time". Journal of Crustacean Biology. 23 (1): 178–186. doi: 10.1651/0278-0372(2003)023[0178:CLNDTT]2.0.CO;2. JSTOR 1549871. S2CID 85905108. Jennifer Viegas (July 23, 2012). "Mysterious, colorful lobsters being caught". Discovery News . Retrieved July 24, 2012.

Tom Stienstra (November 2013). "Maine lobster caught, released at Farallon Islands". San Francisco Chronicle. The underside of the claw of H.americanus is orange or red, while that of H.gammarus is creamy white or very pale red. Red lobster coloration is the typical result of cooking, which is caused by the chemical astaxanthin reacting with boiling water. [27] The estimated odds of catching a live red lobster are 1 in 10 million. [21] [28] Director Bob Bayer from the Lobster Institute at the University of Maine stated in 2016 that "the genetics of red lobsters are not as well understood" when compared to blue lobsters. [29]

a b Elise Takahama (June 6, 2018). " 'Outstanding orange' lobster, one in 30 million, found in Westborough Roche Bros". The Boston Globe. Archived from the original on August 31, 2018 . Retrieved August 31, 2018. John S. Burk (2011). "Northern lobster ( Homarus americanus)". The Wildlife of New England: A Viewer's Guide. University Press of New England. pp.265–266. ISBN 978-1-58465-834-4. The closest relative of H.americanus is the European lobster, Homarus gammarus. The two species are very similar, and can be crossed artificially, although hybrids are unlikely to occur in the wild since their ranges do not overlap. [13] The two species can be distinguished by several characteristics: [14] Life cycle [ edit ] A female lobster carrying eggs on her pleopods. The tail flipper second from left has been notched by researchers to indicate she is an active breeding female. Lulu Grimes (2009). "Seafood". Cook's Book of Everything. Murdoch Books. pp.180–255. ISBN 978-1-74196-033-4.After the next molt, the lobster sinks to the ocean floor and adopts a benthic lifestyle. [40] It molts more and more infrequently, from an initial rate of ten times per year to once every few years. After one year it is around 25–38mm (1–1.5in) long, and after six years it may weigh 0.45 kilograms (1lb). [39] By the time it reaches the minimum landing size, an individual may have molted 25–27 times, and thereafter each molt may signal a 40%–50% increase in weight, and a 14% increase in carapace length. [40] If threatened, adult lobsters will generally choose to fight unless they have lost their claws. [42] Ecology [ edit ] a b Lang, Fred; Govind, C. K.; Costello, Walter J.; Greene, Sharon I. (1997). "Developmental Neuroethology: Changes in Escape and Defensive Behavior During Growth of the Lobster". Science. 197 (4304): 682–685. doi: 10.1126/science.197.4304.682. JSTOR 1744793. PMID 17776272. S2CID 23194965. Government of Canada, Fisheries and Oceans Canada (2018-05-27). "Commercial fisheries for Lobster". dfo-mpo.gc.ca . Retrieved 2021-01-23. a b Gro I. van der Meeren; Josianne Støttrup; Mats Ulmestrand & Jan Atle Knutsen (2006). "Invasive Alien Species Fact Sheet: Homarus americanus" (PDF). Online Database of the North European and Baltic Network on Invasive Alien Species. NOBANIS . Retrieved May 4, 2011.