crab crab species terrestrial crab known crab palm thief largest land living world probably upper size limit terrestrial animals recent times weight grow length leg leg found islands indian_ocean parts pacific_ocean far east distribution palm areas significant human population including mainland australia madagascar crab species genus related terrestrial crabs genus shows number adaptations life land like crabs juvenile crabs use shells protection adults develop tough abdomen stop carrying shell crabs organs known lungs instead gills breathing swim immersed water long developed acute sense smell developed insects use find potential food sources mating occurs dry land females migrate sea release eggs hatch larvae weeks settling sea floor entering shell sexual maturity reached years total lifespan years adult crabs feed fruits nuts seeds fallen trees eat organic matter species popularly associated widely reported climb trees pick opens eat crabs climb trees eventually open collectively significant diet crabs hunted come contact people subject legal protection areas absence precise information iucn lists species data description largest terrestrial terrestrial world reports size vary sources body length weight leg span males generally larger females reach length width body crab like divided section legs abdomen pair legs large claws left larger right pairs crabs large powerful walking legs pointed tips allow crabs climb vertical surfaces fourth pair legs smaller like end allowing young crabs grip inside shell carry protection adults use pair walking climbing pair legs small females tend eggs males mating pair legs usually held inside cavity containing breathing organs difference colour animals found different islands ranging orange red blue regions blue predominant colour places including individuals red derived type crab juveniles use salvaged shells protect soft use broken shells protect unlike crabs adult crabs carry shells instead abdominal chalk constrained physical confines living shell allows species grow larger crabs family like true crabs bends tail underneath body protection hardened abdomen protects crab reduces water loss land periodically adults annually dig long hide vulnerable remains weeks depending size animal takes weeks depending animal size time animal body soft vulnerable stays hidden protection larvae crabs swim left water hour use special organ called lung breathe organ interpreted developmental stage gills lungs significant adaptations crab habitat lung contains tissue similar found gills suited absorption oxygen air water organ expanded increase surface area located placed reduce blood gas distance return distance blood crabs use smallest pair legs clean breathing organs water organs require water properly function crab provides wet legs tissues nearby crabs drink water small transferring addition lung crab additional rudimentary set gills gills comparable number aquatic species families reduced size comparatively surface area sense smell crab developed sense smell uses locate food process works differently depending molecules molecules water molecules air crabs live water specialised organs called antennae determine concentration direction smell crabs live land antennae shorter crabs look like insects insects crab originate different paths need detect air led development remarkably similar organs crabs flick antennae insects enhance reception excellent sense smell detect interesting large distances rotting meat potential food sources catch attention especially research shown system crab brain developed compared areas brain life cycle crabs mate frequently quickly dry land period september especially early june late august male crabs deposit mass abdomen female abdomen opens base thought occur external surface abdomen eggs pass mass eggs occurs land near shore shortly female lays eggs underside abdomen carrying eggs underneath body months time hatching female crab releases eggs ocean usually takes place rocky shores dusk especially high tide egg cases remain female body larvae released female eats egg cases days larvae float zone ocean weeks large number eaten predators larvae pass stages post stage process takes days reaching stage development settle find wear suitably sized shell migrate shoreline terrestrial crabs time visit dry land leave ocean permanently lose ability breathe water crabs change shells grow young crabs find right size use broken pieces shells develop hardened abdomen crab reaches sexual maturity years hatching reach maximum size years distribution crabs live indian_ocean central pacific_ocean distribution closely matches palm western limit range coast tropics cancer mark northern southern limits respectively population evidence crab lived australia madagascar island mauritius longer occurs places swim adults crabs islands larvae christmas island indian_ocean largest population crabs world outnumbered times christmas island red crab indian_ocean populations exist including crab extinct central islands crabs occur islands occur islands northern pacific crab range known gradually believed found single coral island north society group crab far widespread abundant pacific island inhabits large populations exist especially close eastern limit range crab especially frequent abundant palm forest islands marks species eastern limit ecology diet diet crabs consists primarily fruits particularly nuts seeds fallen trees consume organic materials dead animals observed prey crabs like crabs experiment crab observed killing eating rat crabs responsible disappearance remains consuming death skeletal remnants crab ground cut climb tree high drop access meat inside descend trees falling survive fall metres crabs cut holes strong claws eat contents days opened discussed behaviour animal climb trees nuts 1980s able confirm streets report observing studying open wild animal developed special technique covered use claws rip strips starting pores group small circles found outside pores visible crab bang break turn use smaller legs pull white flesh strong claws larger individuals break hard smaller pieces easier consumption habitat considered terrestrial aspects life linked terrestrial existence sea water day crabs live underground rock depending local terrain dig sand loose soil day animal stays hidden reduce water loss heat crabs contain fine strong animal uses resting crab closes entrances claws create moist necessary breathing organs areas large crab population come day gain advantage search food times emerge moist conditions allow breathe easily live exclusively land returning sea release eggs instance abundant kilometres sea relationship human beings adult crabs known predators apart crabs humans large size quality meat means crab extensively hunted rare islands human population crab eaten southeast considered intensive hunting threatened species survival areas crab poisonous depending diet cases crab poisoning occurred instance consumption sea crab crab toxic presence cardiac crab powerful cause noticeable pain human furthermore crab hold extended periods time reports trick crab grip interesting know dilemma gentle soft parts body light material cause crab hold crab known called associated traditional belief ancestral spirits return form animals crab conservation crab populations areas declined locally extinct habitat loss human predation listed iucn red list vulnerable species lack biological data caused assessment amended data conservation management strategies place regions minimum legal size limit restrictions guam ban capture egg bearing females guam hunting non egg bearing adults length place september october november licence bag limit crabs given day season crabs live conservation area marine conservation area covering square kilometres square miles reef western names crab known western scientists sir based account called animal cancer named species cancer latin meaning genus erected containing cancer renamed classified family alongside genus contains terrestrial crabs common names species include crab crab palm thief mirrors animal european languages german
Coconut crab