Primate remains from African crowned eagle (Stephanoaetus coronatus) nests in Ivory Coast's Tai Forest: Implications for primate predation and early hominid taphonomy in South Africa

Abstract

Understanding the initial processes of deposition can help with interpretations of fossil assemblages. Here we discuss the taphonomy of primate remains collected under 16 nests of African crowned eagles (Stephanoaetus coronatus) in the Tai Forest, Ivory Coast. From 1,200 bones collected, including 669 primate bones, we calculated minimum number of individuals (MNI), survivability profiles, and damage profiles using methods identical to those employed by Sanders et al. (2003 J. Hum. Evol. 44:87-105) in their analysis of bones from eagle nests in Uganda. Crowned eagles leave a consistent taphonomic signature on their prey remains; hence, results from our analysis of the Tai assemblage are similar to those from the Ugandan sample. Hindlimb and cranial bones are relatively abundant in the sample, while ribs, vertebrae, carpals, and tarsals do not survive well. Primate crania typically display puncture marks around the eye, long bones remain largely intact, and scapulae exhibit raked breakage. These data have implications for understanding the dynamic between extant primates and one of their principle predators, as well as the taphonomy of hominid-bearing caves in South Africa. We concur with Berger and Clarke (1995 J. Hum. Evol. 29:275-299) that a large raptor could have been responsible for the death of the Taung child, Australopithecus africanus.

Taphonomic analysis of skeletal remains from chimpanzee hunts at Ngogo, Kibale National Park, Uganda

“…Sanders et al (2003) recorded very low frequencies of bone damage by crowned-hawk eagles to cercopithecoid prey at Ngogo (<50% for nearly all skeletal elements of all prey species; cf. McGraw et al, 2006, in the Tai forest sample). At Ngogo, most adult crania were intact but damaged and accompanied by mandibles, though maxillae were sometimes missing (Sanders et al, 2003).…”

“…Adult monkey crania in the Ngogo eagle kill sample, which have the highest bone survivability of all of the skeletal elements (especially in pre-adult individuals), show only subtle signs of damage with few notable marks except for punctures around the orbits and breakage to access the brain. An independently collected prey sample from the Tai forest had signs of slightly more aggressive manipulation from eagle talons and beaks (McGraw et al, 2006), but this is still minimal compared with the chimpanzeedamaged sample from Ngogo.…”

“…6a). On these specimens, all crania (especially orbits) are damaged even more extensively than in crowned hawk-eagle kill samples from Ngogo and the Tai forest in West Africa (Sanders et al, 2003;McGraw et al, 2006).…”

“…At Tai, nearly all mandibles were undamaged (McGraw et al, 2006). In contrast, nearly all scapulae from assemblages at Ngogo and Tai had a unique damage pattern of shattering and raking (Sanders et al, 2003;McGraw et al, 2006) not seen in the Ngogo chimpanzee kill assemblage, but observed in other predatory bird assemblages (Andrews, 1990). Long bones at Ngogo are mostly undamaged by eagles, and a few are minimally damaged on their articular ends (32 to 46% and 24 to 34% in forelimbs and hind limbs, respectively).…”

“…Note the absence of the glenoids (white arrows) and chewing damage resulting in crenulated edges (grey arrows) on the scapular blades. leopards (Simons, 1966;Brain, 1981;de Ruiter and Berger, 2000;Pickering and Carlson, 2002;Pickering, 2003, 2004), black and crowned hawk-eagles (Brain, 1981;Berger and Clarke, 1995;Sanders et al, 2003;McGraw et al, 2006), and humans (Binford 1978(Binford , 1981Maguire et al, 1980;Brain, 1981;Gifford-Gonzalez, 1989;Oliver, 1993;Elkin and Mondini, 2001;Landt, 2004). Comparing general skeletal element patterns or tooth mark frequencies among prey assemblages of very disparate sizes is inappropriate because mammalian predators normally have specific prey size ranges.…”