 However, the degree of sexual dimorphism is debated due to the fragmentary nature of australopith remains.According to A. Zihlman, "Australopithecus" body proportions closely resemble those of bonobos ("Pan paniscus"), leading evolutionary biologist Jeremy Griffith to suggest that bonobos may be phenotypically similar to "Australopithecus".Furthermore, thermoregulatory models suggest that australopiths were fully hair covered, more like chimpanzees and bonobos, and unlike humans.