Rock Crab/Shore Crab (Pachygrapsus crassipes)

Contributed by Dr. Bonnie Becker

Where found:  Hiding in crevices or pools during the day. They will come out to feed at night.

Interesting facts:  These crabs have excellent eyesight. They will eat almost anything edible.

Adaptations:  These crabs are well adapted to semi-terrestrial life. They can tolerate a range of temperatures and salinities. They retain water in their gill chamber, which allows them to breathe out of water for up to three days.

Food:  Rock crabs eat mostly algae scraped off the rocks with their chelae. They will eat larger algae, limpets, hermit crabs, isopods, or detritus. They are active scavengers with a wide variety of tastes.

Life history:  The average brood is 50,000 eggs, which the female carries under her modified tail. Egg-bearing females have been found from February to October, but their peak season is in the summer.

Classification:
Phylum:           Arthropoda (Firm, jointed exoskeleton and jointed appendages)
Class:              Crustacea (Barnacles, Beach hoppers, Shrimps, Lobsters, Crabs, etc.)
SubClass:        Malacostraca (isopods, amphipods, decapods)
Order:             Decapoda (Shrimps, Lobsters, Crabs, etc.)
Infraorder:      Brachyura (“True” crabs)

Last revised 04-May-17