The Solomon Islands and Their Natives

by H. B. Guppy

CHAPTER XV.
GENERAL NATURAL HISTORY NOTES.

Amongst the numerous strange acquaintances which I made in the Solomon Islands, was that of the well known cocoa-nut crab, or Birgus latro; and I take this opportunity of giving my evidence towards the establishment of the fact of its cocoa-nut-eating propensity, for the following reason. When I read my notes on the subject before the Linnean Society of New South Wales on Dec. 27th, 1882,[451] I was surprised at the incredulity shown with reference to this extraordinary habit; and on inquiry, I learned that the evidence on the subject was deficient in one vital point, viz., the production of the writer who had witnessed this habit of the Robber Crab. Accordingly I referred to the various authors who have recorded this habit of the Birgus, and in no single account could I find that the writer had witnessed what he described. Neither Mr. Darwin, Dr. Seemann, Messrs. Tyerman and Bennet, Mr. T. H. Hood, the Rev. Wyatt Gill, nor the numerous authors whose accounts I also examined, seem to have actually witnessed the Birgus opening and eating a cocoa-nut. Herbst[452] was among the first to refer to this habit; whilst, long ago, M. M. Quoy and Gaimard[453] asserted, from their own observation, that the crab was fond of cocoa-nuts, and could be supported on them alone for many months, but they made no allusion to its capability of husking and opening them. The evidence on this point appears to have been always tendered by natives, excepting the account given to Mr. Darwin by Mr. Liesk, which is conclusive in itself.[454] Yet, credulous persons had fair grounds to retain their doubts, although in various works on natural history, popular and otherwise, this habit of the Birgus was described as an undoubted fact. I therefore submit my evidence; leaving to my reader to reply to the query—Can there be any reasonable doubt on the subject?

[451] Proc. Lin. Soc. N.S.W.

[452] Proc. Zool. Soc, 1832, p. 17.

[453] Freycinet’s “Voyage autour du Monde,” 1817-20: Zoologie, p. 536. (Paris, 1824.)

[454] “Journal of Researches,” p. 462.

The Birgus was to be found in most of the islands we visited. It is to be usually observed at or near the coast; but on one occasion, in St. Christoval, I found an individual at a height of 300 feet above the sea. Whilst traversing, in September, 1882, the belt of screw-pines, which borders the beach on the east coast of Malaupaina, the southern island of the Three Sisters, I came upon one of these large crabs, ensconced in the angle between the buttressed roots of a tree, with a full sized cocoa-nut within the reach of its pair of big claws. From the fresh-looking appearance of the shell, it had been evidently, but recently, husked, which operation had been performed more cleanly than if a native had done it. There was an opening at the eye-hole end of the shell of a somewhat regular oblong form, which measured 2 by 1¹⁄₂ inches, and was large enough to admit the powerful claws of the crab.[455] The white kernel, which had the firm consistence of that of the mature nut, had been scooped out to the extent of from 1 to 1¹⁄₂ inches around the aperture; small pieces of the kernel lay on the ground outside the nut, and others were floating about in the milk inside, of which the shell was about a fourth-part full.

[455] This shell was presented to the Australian Museum, Sydney.

I had, without a doubt, disturbed the Birgus in the middle of its meal; but, curiously enough, there were no cocoa-nut palms to be seen within fifty paces of the spot where the crab was found in its retreat. Not only had the shell been very recently husked, but it was evident, from the fresh condition of the milk and kernel, that an interval of less than a couple of hours had elapsed since the opening had been made. There was no possible explanation of the crab having got at the edible portion of the cocoa-nut, except through its own agency. The island is uninhabited, being only occasionally visited by fishing-parties of natives from St. Christoval, none of whom were on the island during the ship’s stay. There was, therefore, the strongest presumptive evidence that the Birgus had not only husked the cocoa-nut, but had also broken the hole at the end, in order to get at the kernel.