TERRESTRIAL ENVIRONMENTS AND ECOLCX3Y 



185 



Fig. 4 a. The glaucothoe of the coconut crab Birgus latro emigrating from the sea to the land; b, The same on a U. S. 

 dime for scale; c, A large adult coconut crab Birgus latro sitting among coconuts. The carapace may attain a width of 

 about 15 cm, and the legs may extend to nearly 1 m; d. An adult Coenobita perlatus In a worn Turbo shell sitting in the 

 crouch of a Toumefortia tree. [Photographs by E. S. Reese.] 



Both Birgus and Coenobita are opportunistic 

 scavengers. They eat animal and vegetable remains as well 

 as fruits and probably bird eggs. I have seen them feeding 

 on dead birds and fish on the beach and dead rats in the 

 forest, and they are readily attracted to almost any kind of 

 human food. Coenobita quickly walk upwind to a garbage 

 dump and may even walk into the warm coals of a camp- 

 fire to retrieve food. Birgus is more secretive and prefers 

 to take food to its burrow. 



The crabs do climb trees for unknown reasons; how- 

 ever, Coenobita especially climb into Scaeuola and 



Toumefortia shrubs in which noddy terns are nesting, and 

 model eggs were found with scratch marks on them. 

 Coconut crabs climb coconut trees, but they have never 

 been observed by Helfman or Reese to cut down coconuts. 

 They are unable to open green coconuts. They do, how- 

 ever, open brown coconuts on the ground. Usually the nut 

 is completely husked, and the reddish brown fiber is often 

 conspicuous at the entrance to a burrow (Fig. 5). The crab 

 apparently pierces the soft eye of the coconut, the one 

 through which the young plant will emerge, and then with 

 its powerful cutting claw cuts open the nut. To my knowl- 



