The spotted hyaena (Crocuta crocuta Erxleben) and the lion (Panthera leo Linnaeus) are two of the most abundant and charismatic large mammalian carnivores in Africa and yet both are experiencing declining populations and significant pressures from environmental change. However, with few exceptions, most studies have focused on influences upon spotted hyaena and lion populations within individual sites, rather than synthesising data from multiple locations. This has impeded the identification of over-arching trends behind the changing biomass of these large predators.

Using Partial Least Squares regression models, influences upon population biomass were therefore investigated, focusing upon prey biomass, temperature, precipitation and vegetation cover. Additionally, as both species are in competition with one other for food, the influence of competition and evidence of environmental partitioning were assessed.

Our results indicate that spotted hyaena biomass is more strongly influenced by environmental conditions than lion, with larger hyaena populations in areas with warmer winters, cooler summers, less drought and more semi-open vegetation cover.

Competition was found to have a negligible influence upon spotted hyaena and lion populations, and environmental partitioning is suggested, with spotted hyaena population biomass greater in areas with more semi-open vegetation cover. Moreover, spotted hyaena is most heavily influenced by the availability of medium-sized prey biomass, whereas lion is influenced more by large size prey biomass. Given the influences identified upon spotted hyaena populations in particular, the results of this study could be used to highlight populations potentially at greatest risk of decline, such as in areas with warming summers and increasingly arid conditions.

The latitude and longitude data does not indicate the exact locations of the species populations. The following information was taken from the Methods section of the paper to further explain the location points:

'Unless otherwise stated in the original publications or by Hatton et al. (2015), the boundaries of the sites were taken to be the entire area, i.e. the entire national park, national reserve, game reserve, or district. The Serengeti ecosystem datasets in Hatton et al. (2015) were derived from a number of different publications, therefore, the boundaries of this site were taken from a map of the Serengeti ecosystem (Hopcraft 2008).'

'The centre point of each site was the point where the median latitude and longitude intersected. Median latitude was calculated from the most northerly and southerly latitudes of each location. The same was performed for longitude. This was done using Image Landsat Google Earth Pro (2013).'

'For each site, the type of vegetation in each pixel (each 1 km2) was recorded along two transects with widths of 1 km. The north-south transect ran through the centre point of the site, to the most northern and southern boundaries. The equivalent procedure was conducted for the east-west transect.'