Author Correction: Chimpanzee ethnography reveals unexpected cultural diversity.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Forest elephant movement and habitat use in a tropical forest-grassland mosaic in Gabon.

Poaching of forest elephants (Loxodonta cyclotis) for ivory has decimated their populations in Central Africa. Studying elephant movement can provide insight into habitat and resource use to reveal where, when, and why they move and guide conservation efforts. We fitted 17 forest elephants with global positioning system (GPS) collars in 2015 and 2016 in the tropical forest-grassland mosaic of the Wonga Wongué Presidential Reserve (WW), Gabon. Using the location data, we quantified movement distances, home ranges, and habitat use to examine the environmental drivers of elephant movements and predict where elephants occur spatially and temporally. Forest elephants, on average, traveled 2,840 km annually and had home ranges of 713 km2, with males covering significantly larger home ranges than females. Forest elephants demonstrated both daily and seasonal movement patterns. Daily, they moved between forest and grassland at dawn and dusk. Seasonally, they spent proportionally more time in grassland than forest during the short-wet season when grasses recruit. Forest elephants also traveled faster during the short-wet season when fruit availability was greatest, likely reflecting long, direct movements to preferred fruiting tree species. Forest elephants tended to select areas with high tree and shrub density that afford cover and browse. When villages occurred in their home ranges elephants spent a disproportionate amount of time near them, particularly in the dry season, probably for access to agricultural crops and preferred habitat. Given the importance of the grassland habitat for elephants, maintenance of the forest-grassland matrix is a conservation priority in WW. Law enforcement, outreach, and education should focus on areas of potential human-elephant conflict near villages along the borders of the reserve. GPS-tracking should be extended into multi-use areas in the peripheries of protected areas to evaluate the effects of human disturbance on elephant movements and to maintain connectivity among elephant populations in Gabon.

Chimpanzee tool use for honey and termite extraction in Central Africa.

Observations are presented primarily from two study sites located in the extreme southwestern tip of the Central African Republic. The use of flexible stalks and rigid sticks to extract termites from mounds and pounding, prying, and digging tools to penetrate melipone, honey bee, and ground-dwelling bee hives by Pan t. troglodytes are documented or inferred from circumstantial evidence. Functionally, termite extraction tools were similar to other locations in west and central Africa, but the plant species used were considerably different. Extraction of bees using large pieces of wood as pounding tools has not been recorded elsewhere in wild chimpanzees. No environmental factor that differs between the east and west of the range of P. t. troglodytes that would cause the difference in tool use was identified. © 1994 Wiley-Liss, Inc.

Census of gorillas in northern Republic of Congo.

We censused gorilla populations in northern Congo from February to April 1989 and June 1990. The objective was to provide the first quantitative data from a variety of sites on gorilla populations from a country that had unknown but potentially high populations. The method used was a census of nests along strip transects. A total of 401.0 km of transects was sampled in four different study areas. The overall density calculated for all transects was 0.4 nesting gorillas/km2. The highest density, 1.2 nesting gorillas/km2, was found in the vast Likouala swamp area of north central Congo. The two northern sites showed low densities of 0.1 and 0.2 nesting gorillas/km2, respectively. The northwestern site showed an intermediate density of 0.6 nesting gorillas/km2. The vegetation type with the highest density was swamp forest with 2.4 nesting gorillas/km2. The limited sample presented shows that gorillas are widespread and common in northern Congo, even in the swamp forests previously considered unsuitable as gorilla habitat. It is probable that Congo holds the largest population of gorillas in Africa after Gabon. © 1992 Wiley-Liss, Inc.

The changing landscape of clinical research: top grading your research center for success.

The impact of innovation and the effectiveness of research on healthcare is nothing short of remarkable; one need only to reflect on the breakthroughs of the past quarter century to understand the accomplishments of physician investigators and the benefits their research have bestowed upon society. Yet the success of any clinical trial relies heavily on the ability of the investigator to understand his/her role in compliant trial conduct, to evaluate the merits of an investigational product, the protocol design, willingness of subjects to participate in clinical trials, and the ability of his/her site to meet sponsor expectations. This article provides basic insight into the challenges and opportunities offered by clinical trial participation, while assisting new and experienced investigators in selecting an appropriate research model for their practice.