The large, frontal claws are characteristic of true lobsters, grouped in the family Homaridae
. Members of this family include the American lobster (Homarus americanus) and the European lobster (H.
Agonistic encounters in competition for space, shelter, and access to mates or food are very common in crustaceans and have been studied extensively in different orders and families (Dingle, 1983; Hyatt, 1983) such as mantis shrimp (Stomatopoda; Caldwell and Dingle, 1975), freshwater prawns (Palaemonidae; Barki et al., 1991), lobsters (Homaridae
; Huber and Kravitz, 1995), crayfish (Astacidae, Cambaridae and Parastacidae; Copp, 1986; Soderback, 1991; Pavey and Fielder, 1996), and hermit crabs (Paguridae; Elwood and Neil 1992).