Abstract. − Previous analysis of sex differentiable terms (or SDTs, words that distinguish sexes in humans and nonhuman animals) has shown how they can coincide with folk zoological life-form taxa and, at the same time, provide evidence of covert taxa, notably a category of “mammals.” In this article, the system of SDTs employed by the Nage of eastern Indonesia is compared with a similar system found in Central America, among the Chuj Mayans. Similarities and differences between the two systems are explored, in some instances with further reference to English SDTs, and consideration is given to how such terms may reveal universal tendencies in ways human languages register perceptual difference among animal kinds. [Central America, eastern Indonesia, Nage, Chuj Maya, ethnotaxonomy, sex differentiable term, life-form taxa]