Mr. Blaauw has ascertained by frequent observation that the period of gestation in the White-tailed Gnu varies from 8¼ to 8½ months. Only a single young one has ever been produced at a birth. The female suckles her young for seven or eight months, but it commences to eat grass when about a week old.
In the ‘Proceedings’ of the Zoological Society of London, Mr. Blaauw has published an article on the development of the horns of the young Gnu, two of the figures of which we are enabled to reproduce here by the kind permission of that Society. The first figure (15 b) represents the first stage of the horns, in which they are perfectly straight and more or less divergent; the second figure (15 c) represents the horns when the animal is about 19 months old. The former straight portion has now become the terminal half, and the basal portion, though not yet quite fully developed, inclines downwards and outwards. The bases of the horns are still far apart, and there is a wide piece of hairy scalp between them. In the adult stage (as shown in Plate XII.) the basal ends of the horns become enormously swollen (especially in the male) and nearly meet together in the middle line. It should be further remarked that these swollen basal portions, which are smooth at first, become excessively corrugated and more highly developed when the animals get old.
Fig. 15 b.
Horns of young Gnu (11 weeks old).
(P. Z. S. 1889, p. 2.)
Fig. 15 c.
Horns of young Gnu (19 months old).
(P. Z. S. 1889, p. 3.)