Sometimes, a picture truly can convey more than a thousand words. This is certainly the case where the discovery of the mandrill is concerned. For, although vague descriptions of monkeys that might possibly have been mandrills can be found in the ancient literature, there are no accurate accounts of the animal. The earliest unequivocal record of the mandrill's existence is a drawing, which appears in the published works of the sixteenth century Swiss naturalist and prolific encyclopaedist Conrad Gesner. Gesner died of the plague in 1565, when he was just 49 years of age. Yet, during his comparatively short life, he had produced intellectually diverse and monumental works. These included the Bibliotheca Universalis, which listed in Latin, Greek and Hebrew 1800 authors together with critiques of their various publications. Gesner's Mithridates De Differentiis Linguarum gave an account of all the 130 languages that were then known to scholars. However, it is his Historiae Animalium (1551–1558) for which he is best remembered. Four volumes of Gesner's great work on natural history were published in Zurich during his lifetime, and a later German edition, Das Thierbuch (1606), contained the drawing of a mandrill that is included here in Figure 1.1.

Gesner thought that this rather bristly and dog-like creature might be some type of hyaena! Yet, for all its limitations, the drawing is clearly an adult male mandrill, as evidenced by its stocky build, stumpy tail, and large rump. The hands and feet are plainly those of a monkey. However, the head is poorly rendered, for although the snout is quite prominent, it is foreshortened and lacks the longitudinal paranasal swellings that are so characteristic of mature male mandrills. Nor is there any indication of the bright bare areas of sexual skin, the beard, crest and thick pelage of this species. For comparative purposes, these features are shown in the modern drawing of a male mandrill included in Figure 1.1.