"The Nyala (Nyala angasii) presents the field researcher with a particular challenge: the male and female differ so markedly in appearance that early naturalists described them as separate species. The female is small, rufous-brown, white-striped, without horns. The male is larger, slate-dark, shaggy-maned, carrying spiral horns, with orange-yellow legs that appear to belong to a third animal entirely. The author arrived at a comparable conclusion before revising. He notes, in mitigation, that he is in reasonable company. The nyala favours dense riverine thickets near water, which limits visibility, which is, in retrospect, relevant."
The second entry in the Colonel's nyala notes began: Second species confirmed in thicket. Smaller than the large dark male. Rufous colouring, white stripes, no horns. Presence alongside larger individual suggests interspecies tolerance or shared resource.
He had been writing this kind of entry for four days.
On the fifth day he watched a large dark male perform what he had been cataloguing as aggressive display behaviour — the stiff-legged walk, the mane raising, the tail curling upward, the lateral presentation to whatever the display was directed at, which on this occasion was a younger male at the thicket's edge. The Colonel wrote carefully: Display behaviour: elevated mane, lateral stance, apparent size increase. Territorial. Probable threat to rival.
He watched the mane. He watched it with the specific attention of a man who has spent enough time watching animals to notice when something changes between one moment and the next. The mane did not simply raise. As it raised it spread — the long guard hairs extending outward from the dorsal crest, adding width and height simultaneously, the dark body beneath it suddenly presenting a profile considerably larger than it had been five seconds previously.
He wrote: Mane elevation appears to increase apparent size. Optical effect — fur as engineering.
He looked at this. He had not written anything quite like it before. He looked at the male, who had achieved his apparent size increase and was now holding it, presenting the maximum available silhouette to the younger male, who was reassessing his morning accordingly.
Not threat display, the Colonel revised. Size illusion. The animal is manufacturing himself.
He looked at the male and then at the thicket where the smaller rufous female — his second species — had been feeding.
He looked at his notes.
He looked at the male.
He crossed out Second species confirmed in thicket on the first page of his nyala notes and replaced it with a word he had written twice already in this volume. He wrote: Incorrect.
He sat for some time.
The female had been in the dappled light under the large sycamore fig for the better part of an hour before the Colonel noticed her.
He had walked past the tree. He had been going to the waterhole — the standard morning circuit — and the tree was on his path, and he had passed it at eight-fifteen and noted nothing. At nine he had returned by the same route. He had passed it again. At half past nine Cetshwayo said something.
"She is there," Cetshwayo said. Not urgently. In the manner of a man completing information the Colonel appeared to lack.