1911 Encyclopædia Britannica/Rhea (bird)

​RHEA, the name given in 1752 by P. H. G. Möhring^[1] to aSouth American bird which, though long before known anddescribed by the earlier writers—Nieremberg, Marcgrav andPiso (the last of whom has a recognizable but rude figure ofit)—had been without any distinctive scientific appellation.Adopted a few years later by M. J. Brisson, the name has sincepassed into general use, especially among English authors, forwhat their predecessors had called the American ostrich; buton the European continent the bird is commonly called Nandu,^[2]a word corrupted from a name it is said to have borne amongthe aboriginal inhabitants of Brazil, where the Portuguesesettlers called it ema (see Emeu). The resemblance of the rheato the ostrich (q.v.) was at once perceived, but the differencesbetween them are also very evident. The former, for instance,has three instead of two toes on each foot, it has no apparenttail, its wings are far better developed, and when folded coverthe body, and its head and neck are clothed with feathers, whileinternal distinctions of still deeper significance have since been ​dwelt upon by T. H. Huxley (Proc. Zool. Society, 1867, pp.420–422) and W. A. Forbes (op. cit., 1881, pp. 784–87). There canbe little doubt that they should be regarded as types of as manyorders—Struthiones and Rheae—of the subclass Ratitae. Structuralcharacters no less important separate the rheas fromthe emeus; the former can be readily recognized by the roundedform of their contour-feathers, which want the hyporrhachisor after-shaft that in the emeus and cassowaries is so long asto equal the main shaft, and contributes to give these lattergroups the appearance of being covered with shaggy hair. Thefeathers of the rhea have a considerable market value, and forthe purpose of trade in them it is annually killed by thousands,so that^[3] its total extinction as a wild animal is probably onlya question of time. It is polygamous, and the male performsthe duty of incubation, brooding more than a score of eggs,the produce of several females—facts known to Nierembergmore than two hundred and fifty years since, but hardly acceptedby naturalists until recently. No examples of this bird seemto have been brought to Europe before the beginning of thepresent century, and accordingly the descriptions previouslygiven of it by systematic writers were taken at second hand andwere mostly defective if not misleading. In 1803 J. Lathamissued a wretched figure of the species from a half-grown specimenin the Leverian Museum, and twenty years later said hehad seen only one other, and that still younger, in Bullock'scollection (Gen. Hist. Birds, viii. p. 379).^[4] A bird living inconfinement at Strassburg in 1806 was, however, described andfigured by Hammer in 1808 (Ann. du Muséum, xii. pp.427–433,pl. 39). In England the Report of the Zoological Societyfor 1833 announced the rhea as having been exhibited for thefirst time in its gardens during the preceding twelvemonth.Since then many other living examples have been introduced,and it has bred both there and in many private parks in Britain.

Though considerably smaller than the ostrich, and wantingits fine plumes, the rhea in general aspect far more resemblesthat bird than the other Ratitae. The feathers of the head andneck, except on the crown and nape, where they are dark brown.are dingy white, and those of the body ash-coloured tinged withbrown, while on the breast they are brownish-black, and on thebelly and thighs white. In the course of the memorable voyageof the “Beagle,” C. Darwin came to hear of another kind ofrhea, called by his informants Avestruz petise, and at PortDesire on the east coast of Patagonia he obtained an exampleof it, the imperfect skin of which enabled J. Gould to describeit (Proc. Zool. Society, 1837, p. 35) as a second species of thegenus, naming it after its discoverer. Rhea darwini differsin several well-marked characters from the earlier knownR. americana. Its bill is shorter than its head; its tarsi arereticulated instead of scutellated in front, with the upper partfeathered instead of being bare; and the plumage of its bodyand wings is very different, each feather being tipped with adistinct whitish band, while that of the head and neck is greyish-brown.A further distinction is also asserted to be shown bythe eggs—those of R. americana being of a yellowish-white,while those of R. darwini have a bluish tinge. Some yearsafterwards P. L. Sclater described (op. cit., 1860, p. 207) a thirdand smaller species, closely resembling the R. americana, buthaving apparently a longer bill, whence he named it R.macrorhyncha, more slender tarsi, and shorter toes, while its generalcolour is very much darker, the body and wings being of abrownish-grey mixed with black. The precise geographicalrange of these three species is still undetermined. While R.americana is known to extend from Paraguay and southernBrazil through the La Plata region to an uncertain distance inPatagonia, R. darwin seems to be the proper inhabitant of thecountry last named, though M. Claraz asserts (op. cit., 1885,p. 324) that it is occasionally found to the northward of the RioNegro, which had formerly been regarded as its limit, and,moreover, that flocks of the two species commingled may bevery frequently seen in the district between that river and theRio Colorado. On the “pampas” R. americana is said toassociate with herds of deer (Cariacus campestris), and R.darwini to be the constant companion of guanacos (Lamahuanaco)—just as in Africa the ostrich seeks the society ofzebras and antelopes. As for R. macrorhyncha, it was found byW. A. Forbes (Ibis, 1881, pp. 360, 361) to inhabit the dry andopen “servoẽs” of north-eastern Brazil, a discovery the moreinteresting since it was in that part of the country that Marcgravand Piso became acquainted with a bird of this kind, though theexistence of any species of rhea in the district had been longoverlooked by or unknown to succeeding travellers.

Besides the works above named and those of other recognizedauthorities on the ornithology of South America such as Azara,Prince Max of Wied, Professor Burmeister and others, more or lessvaluable information on the subject is to be found in Darwin'sVoyage, Dr Böcking's “Monographie des Nandu” in(Wiegmann's Archiv für Naturgeschichte (1863, i. pp. 213–41); R. O.Cunningham's Natural History of the Strait of Magellan and paperin the Zoological Society's Proceedings for 1871 (pp. 105–110),as well as H. F. Gadow's still more important anatomicalcontributions in the same journal for 1885 (pp. 308 seq.) (A. N.)