Wild chimpanzees deprived a leopard of its kill: Implications for the origin of hominin confrontational scavenging.

This study reports the first observed case of wild chimpanzees (Pan troglodytes) obtaining animal prey freshly killed by a sympatric leopard (Panthera pardus) and scavenging it with the leopard still nearby. This observation has important implications for the emergence of confrontational scavenging, which may have played a significant role in human evolution. Many scholars agree that eating meat became important during human evolution, and hominins first obtained meat by scavenging.

A newborn infant chimpanzee snatched and cannibalized immediately after birth: Implications for "maternity leave" in wild chimpanzee.

Objectives: This study reports on the first observed case of a wild chimpanzee infant being snatched immediately after delivery and consequently cannibalized by an adult male in the Mahale Mountains, Tanzania. We demonstrate "maternity leave" from long-term data from the Mahale M group and suggest that it functions as a possible counterstrategy of mother chimpanzees against the risk of infanticide soon after delivery.

Materials And Methods: The subjects of this study were the M group chimpanzees at Mahale Mountains, Tanzania.

Ranging behavior of Mahale chimpanzees: a 16 year study.

We have analyzed the ranging patterns of the Mimikire group (M group) of chimpanzees in the Mahale Mountains National Park, Tanzania. During 16 years, the chimpanzees moved over a total area of 25.2 or 27.

Natural history of Camponotus ant-fishing by the M group chimpanzees at the Mahale Mountains National Park, Tanzania.

The aim of this study was to provide basic data on ant-fishing behavior among the M group chimpanzees at the Mahale Mountains National Park, Tanzania. Ant-fishing is a type of tool-using behavior that has been exhibited by Mahale chimpanzees when feeding upon arboreal carpenter ants (Camponotus spp.) since the 1970s, and is now regarded as a candidate of wild chimpanzee culture.

Prevalence of muzzle-rubbing and hand-rubbing behavior in wild chimpanzees in Mahale Mountains National Park, Tanzania.

In 1998, four chimpanzees in the Mahale Mountains National Park, Tanzania, were observed wiping their mouths with non-detached leaves or stalks of grass, or rubbing their mouths with a tree trunk or branch, especially while eating lemons. The number of mouth-wiping/rubbing individuals increased to 18 in 1999. By 2005, 29 chimpanzees were documented wiping/rubbing their muzzles in this way.

Tool-use for drinking water by immature chimpanzees of Mahale: prevalence of an unessential behavior.

Use of leaves or sticks for drinking water has only rarely been observed during long-term study of wild chimpanzees (Pan troglodytes schweinfurthii) at Mahale. Recently, however, we observed 42 episodes of tool-use for drinking water (73 tools and two cases of using "tool-sets") between 1999 and 2004. Interestingly, all of the performers were immature chimpanzees aged from 2 to 10 years.