All about me on the fertile soil, among decaying leaves and luxuriant vines, I saw these nuts, carrying on their mysterious and powerful life in the unheeded forest depths.  Here and there a half-domestic pig was harrying one with thrusting snout.  These pigs, which we think stupid, know well that the sun will the sooner cause a sprouting nut to break open, and they roll the fallen nut into the sunlight to hasten their stomachs’ gratification, though with sufficient labor they can get to the meat with their teeth.

There is a crab here, too, that could teach even the wisest, sun-employing pig some tricks in economics.  He is the last word in adaptation to environment, with an uncanny knowledge that makes the uninformed look askance at the tale-teller.  These crabs climb cocoanut-trees to procure their favorite food.  They dote on cocoanuts, the ripe, full-meated sort.  They are able to enjoy them by various endeavors demanding strength, cleverness, an apparent understanding of the effect of striking an object against a harder one, and of the velocity caused by gravity.  Nuts that resist their attempts to open them, they carry to great heights, to drop them and thus break their shells.

These crabs are called by the scientists Birgos latro, by the Marquesans tupa, by the Paumotans kaveu, and by the Tahitians, ua vahi haari.  It was a never-failing entertainment on my walks in the Paumotas to observe these great creatures, light-brown or reddish in color, more than two feet in length, stalking about with their bodies a foot from the ground, supported by two pairs of central legs.  They can exist at least twenty-four hours without visiting the water, of which they carry a supply in reservoirs on both sides of the cephalothorax, keeping their gills moist.

[Illustration:  A Marquesan home on a paepae]

[Illustration:  Isle of Barking Dogs]

They live in large deep burrows in the cocoanut-groves, which they fill with husks, so that the natives often rob them to procure a quick supply of fuel.  These dens are contrived for speedy entry when pursued.  Terrifying as they appear when surprised on land, they scuttle for safety either to a hole or to the sea, with an agility astounding in a creature so awkward in appearance.  Though they may be seen about at all hours of the day, they make forays upon the cocoanuts only at night.

Darwin first saw these creatures in the Indian Ocean, and said that they seek the sea every night to moisten their branchiae.  The young are hatched and live for some time on the sea-coast, venturing far from water only as they grow older.  Darwin said that their feat in entering the cocoanut “is as curious a case of instinct as was ever heard of, and likewise of adaptation in structure between two objects apparently so remote from each other in the scheme of nature, as a crab and a cocoanut-tree.”