Plant thorns and spines had these effects on the feeding behaviour of the three species of browsing ungulate that we studied, kudu, impala and domestic goats: (i) bite sizes were restricted, in most cases to single leaves or leaf clusters; (ii) hooked thorns retarded biting rates; (iii) the acceptability of those plant species offering small leaf size in conjunction with prickles was lower, at least for the kudus, than those of other palatable plant species; (iv) the inhibitory effect of prickles on feeding was much less for the smaller impalas and goats than for the larger kudus; (v) from certain hook-thorned species the kudus bit off shoot ends despite their prickles; (vi) for certain straight-thorned species the kudus compensated partially for the slow eating rates obtained by extending their feeding durations per encounter. Most spinescent species were similar in their acceptability to the ungulates to unarmed palatable species, despite higher crude protein contents in their foliage than the latter. Such structural features furthermore reduce the tissue losses incurred by plants per encounter by a large ungulate herbivore, by restricting the eating rates that the animals obtain. In this way prickles function to restrict foliage losses to large herbivores below the levels that might otherwise occur.

The palatability of 14 species of woody plant was assessed for three species of browsing ruminant, namely kudus, impalas and goats. Results show that palatability was most clearly related to leaf contents of condensed tannins. The effect was a threshold one, with all plants containing more than 5% condensed tannins being rejected as food during the wet season period. In contrast palatability was not influenced by concentrations of protein-precipitating polyphenols, and only weakly related to contents of nitrogen, phosphorus, cations, fibre components and other secondary metabolites. Insect herbivory shows a different pattern. These findings support the hypotheses that (i) condensed tannins function to protect plant cell walls against microbial attack; (ii) hydrolyzable tannins function to inactivate the digestive enzymes of insect herbivores. Large mammalian herbivores are influenced by condensed tannins due to their dependance upon microbial fermentation of plant cell walls for part of their energy needs.

This paper presents preliminary evidence that kleptoparasitism by spotted hyaenas may influence optimal hunting group size of lions. In the absence of adult male lions, hyaenas can drive female and subadult lions off their kills provided they outnumber the lions by a factor of four. Hence the larger the group of lions on the kill, the greater their chance of defending their food against invading hyaenas. At Savuti, where there was a shortage of adult male lions, the groups of female and subadult lions lost almost 20% of their food to hyaenas. Losses were most frequent for those living in small groups. These lions were often satiated by the time the hyaenas acquired the kill, so the hyaenas did not cause immediate need, yet constituted a constant energy drain on lions by forcing them to hunt more frequently. The implications of these observations for modelling optimal hunting group size of lions are discussed. ResumeCet article apporte une premiere evidence du fait que le kleptoparasitisme dii aux hyenes tachetkes peut influencer la taille optimale des groupes de lions en chasse. En I'abscence de lion mile adulte, les hyenes peuvent chasser les femelles et les subadultes de leur proie pourvu qu'elles soient plus nombreuses que les lions, selon un facteur de quatre. Des lors, plus grand est le group de lions, plus grandes sont leurs chances de dtfendre leur norriture contre le harcelement des hyenes. A Savuti, od il y avait trop peu de lions mBles adultes, les groupes de lions femelles et subadultes perdaient presque 20% de leur norriture au profit des hyenes. Les pertes etaient les plus frequentes pour ceux qui vivaient en petits groupes. Ces lions etaient souvent rassasies quand les hyenes s'appropriaient la proie, de sorte qu'elles ne causaient pas de besoin immkdiat, mais elles constituaient une ponction constante de 1'Cnergie des lions en les forCant a chasser plus souvent. On discute des implications de ces observations pour tttablir la taille idkale des groupes de lions en chasse.

With 6 figures in the text)Hunting group size, hunting rates and hunting success were monitored over a seven-year period among members of one large clan of spotted hyenas (Crocuta crocuta) inhabiting the Masai Mara National Reserve, in south-west Kenya. Prey availability varied seasonally in this study area, and hyenas tended to hunt whichever prey species were most abundant during each month of the year. Over 75% of 272 hunting attempts were made by lone hyenas, even when they hunted antelope three times their own body mass, such as wildebeest and topi. Of all prey that were commonly hunted, only zebra were usually hunted in groups. Approximately one-third of all hunting attempts resulted in prey capture. Although no significant sex differences were observed in juvenile or adult hunting rates, lowranking adult females hunted at significantly higher hourly rates than did higher-ranking females. Hunting success was not influenced by the social rank of hunters, but hunting group size and hunter's age strongly influenced success. Young hyenas were poor hunters, and did not achieve adult competency levels until they were 5-6 years old.

BackgroundThe movement behavior of an animal is determined by extrinsic and intrinsic factors that operate at multiple spatio-temporal scales, yet much of our knowledge of animal movement comes from studies that examine only one or two scales concurrently. Understanding the drivers of animal movement across multiple scales is crucial for understanding the fundamentals of movement ecology, predicting changes in distribution, describing disease dynamics, and identifying efficient methods of wildlife conservation and management.MethodsWe obtained over 400,000 GPS locations of wild pigs from 13 different studies spanning six states in southern U.S.A., and quantified movement rates and home range size within a single analytical framework. We used a generalized additive mixed model framework to quantify the effects of five broad predictor categories on movement: individual-level attributes, geographic factors, landscape attributes, meteorological conditions, and temporal variables. We examined effects of predictors across three temporal scales: daily, monthly, and using all data during the study period. We considered both local environmental factors such as daily weather data and distance to various resources on the landscape, as well as factors acting at a broader spatial scale such as ecoregion and season.ResultsWe found meteorological variables (temperature and pressure), landscape features (distance to water sources), a broad-scale geographic factor (ecoregion), and individual-level characteristics (sex-age class), drove wild pig movement across all scales, but both the magnitude and shape of covariate relationships to movement differed across temporal scales.ConclusionsThe analytical framework we present can be used to assess movement patterns arising from multiple data sources for a range of species while accounting for spatio-temporal correlations. Our analyses show the magnitude by which reaction norms can change based on the temporal scale of response data, illustrating the importance of appropriately defining temporal scales of both the movement response and covariates depending on the intended implications of research (e.g., predicting effects of movement due to climate change versus planning local-scale management). We argue that consideration of multiple spatial scales within the same framework (rather than comparing across separate studies post-hoc) gives a more accurate quantification of cross-scale spatial effects by appropriately accounting for error correlation.Electronic supplementary materialThe online version of this article (doi:10.1186/s40462-017-0105-1) contains supplementary material, which is available to authorized users.