Coenobita clypeatus is a land hermit crab found in coastal forest and rocky shores all over Puerto Rico. As an anatomical trait, its carapace covers only its cephalothoraxes, so it uses a wide variety of gastropod shells to protect their abdomen from dehydration and predations. Populations of land hermit crab C. clipeatus had been well studied in
We captured a total of 195 individuals. There is difference between the densities of hermit crabs in the rocky shore (1 individual /25 m2) and in the coastal forest (7 individual/ 25 m2). Hermit crabs in the coastal forest had a larger chelae size (6.7 mm ± 2.84) than the ones in the rocky shores (2.4 ±9.59). We identified two species of gastropod in the rocky shores and seven species in the coastal forest. Shell aperture, width and length varied with gastropod species. Preliminary results showed a difference in size of chelae and gastropod shell use between the two sampling sites. Coastal forest offers a diverse environment for the hermit crabs in terms of availability of shells and protection against predators. These factors have an effect on the growth and survival of the species. Protection of coastal forests and control of beachcombers will benefit the populations of hermit crabs.