AMERICAN FORESTRY 



111 



TREE CLIMBING CRAB 



BY H. A. ZIMMERMAN 



'T'HE robber, or cocoanut crab, has been known for 

 " some centuries but until lately doubts have existed 

 whether these crustaceans actually climb trees to reach 

 the cocoanut. The picture shown here, taken on Christ- 

 mas Island, should do away with all uncertainty on this 

 point. The appearance of these giant creatures crawling 

 through the woods makes one feel decidedly creepy. The 

 animals are easily frightened, and scuttle off backwards 

 at the slightest alarm. They live not only on cocoanuts, 

 but feed on fruits of various kinds, especially those of 

 the sago-palm, while carrion of all sorts even the 

 bodies of their own relatives do not come amiss. At 

 one time, when rats swarmed in the forest at night, the 

 crabs restricted their depredations to the daylight hours ; 

 but now that rats have disappeared, even at night, camp 

 utensils are not safe from their claws. In fact, they 



THE ROBBER CRAB 

 Horrible to look at and with worse habits for he is a "thief in the night." 



have been known to carry away cooking utensils, bot- 

 tles and clothes. The robber crab's method of carrying 

 cocoanuts is to strip them of their husks and then to hold 

 the nut under some of its walking legs, while it retires, 

 raised high on the tips of those legs not used for this 

 purpose. Darwin has graphically described how it tears 

 the husk from the cocoanuts and hammers on the round 

 depressions at one end until entrance is effected. 



This crab lives in a hole in the earth under trees, lining 

 its burrow with the fibers of the cocoanut husks. It has 

 an almost lung-like modification of the gill cavity for 

 breathing air directly, yet visits the sea annually in 

 droves to spawn. In climbing this crab scarcely uses 

 its large claws, but clings to the tree with the sharp 

 points of its walking legs. It can also climb almost ver- 

 tical rock faces. 



A DOUBLE HICKORY NUT 



BY ROBERT SPARKS WALKER 



T'WO nuts in one shell is a very rare occurrence with 

 * the hickory nut family. But why should not there 

 be such a variety ? The chestnut would be less attractive 

 if not less productive were it not for the fact that the 

 prickly burr economizes in housing two, three arid some- 

 times more nuts. Suppose that each single chestnut had 

 an individual burr. This would draw heavily upon the 

 vigor of the tree, and in all probability would result in a 

 smaller nut than those multi-producing burrs. 



So far as known, the only hickory tree producing dou- 

 ble nuts is found growing in the extreme southeastern 

 part of the state of Tennessee. From close observation 

 covering a period of four years, it appears that only a 





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THE TREE, AND THE NUT 



So far as is now known, this is the only hickory tree in this country 



producing double hickory nuts. 



portion of the branches producing fruit buds are mutat- 

 ing. Mutating is simply a process of changing styles in 

 the vegetable kingdom. From a third to one-half of the 

 branches produce double nuts, and these are isolated in a 

 position we will call on the west side of the tree. These, 

 however, never have failed to produce the double nuts, 

 as shown in the photograph. The specimens are all 

 alike, excepting on some branches located on the east 

 side of the tree, which appear to be in the process of 

 "doubling up." 



