Males reach sexual maturity at seven months, females require 11-12 months. Mating occurs after the female molts while her shell is still soft. Fertilization is internal. A medium-sized female carries up to 50,000 eggs and produces one or two broods a year. The Striped Shore Crab is faster than many of it relatives, so fast that it can catch flies with its chela or front claws.
Crabs have a set of chitinous teeth in their stomach to aid with digestion.
This crab is able to forage for food on both land and in the water. P. crassipes can stay out of water in a shaded area for up to 70 hrs.