Stable carbon isotope reconstruction of ungulate diet changes through the seasonal cycle
We analysed stable carbon isotope ratios (δ13C) in faeces of 11 African ungulate species from three South African savanna environments to determine whether this approach is sufficiently sensitive to record short-term seasonal diet changes in browsers (BR), mixed-feeders (IM), and grazers (GR). At monthly intervals, faecal δ13C revealed variations in proportions of C3 (browse) to […]
The dissociation of the fluid and particle phase in the forestomach as a physiological characteristic of large grazing ruminants: an evaluation of available, comparable ruminant passage data
Whether differences in digestive physiology exist between different ruminant feeding types has been an ongoing debate. In this regard, potential differences in ingesta retention have been understood to be of particular importance. We analyzed a data pool in which only mean retention time (MRT) data for the ruminoreticulum (RR) were collated that were obtained using […]
Higher masseter muscle mass in grazing than in browsing ruminants.
Using cranioskeletal measurements, several studies have generated evidence that grazing ruminants have a more pronounced mastication apparatus, in terms of muscle insertion areas and protuberances, than browsing ruminants, with the resulting hypothesis that grazers should have larger, heavier chewing muscles than browsers. However, the only investigation of this so far [Axmacher and Hofmann (J Zool […]
Enamel ridge alignment in upper molars of ruminants in relation to their natural diet
Although it is generally thought that dental design reflects mechanical adaptations to particular diets, concrete concepts of such adaptations beyond the evolution of hypsodonty are largely missing. We investigated the alignment of enamel ridges in the occlusal molar surface of 37 ruminant species and tested for correlations with the percentage of grass in the natural […]
Convergence in the macroscopic anatomy of the reticulum in wild ruminant species of different feeding types and a new resulting hypothesis on reticular function
The reticulum is the second part of the ruminant forestomach, located between the rumen and the omasum and characterized by honeycomb-like internal mucosa. With its fluid contents, it plays a decisive role in particle separation. Differences among species have been linked to their feeding style. We investigated whether reticulum size (absolute and in relation to […]
Digestive tract pathology of captive giraffe (Giraffa Camelopardalis). A unifying hypothesis
Captive giraffe (Giraffa Camelopardalis) are affected by four major pathological conditions linked to their nutrition: (1) the so-called “peracute mortality syndrome” with complete absence and serious atrophy of body fat stores, (2) phytobezoars, i.e. Fibrous conglomerates of plant material, in the omasum and abomasums (3) rumen acidosis or (4) partial loss of dorsal ruminal papillation. […]
Influence of ration composition on nutritive and digestive variables in captive giraffes (Giraffa camelopardalis) indicating the appropriateness of feeding practice
The nutrition of captive giraffe (Giraffa camelopardalis), a browsing ruminant, is challenging because browse availability is limited in zoos and rations need to be composed of compensatory feeds. In this study, ration composition for giraffes in 12 German zoos was documented and linked to animal variables that indicate suitability of nutrition. Rations differed in proportion […]
Fire history and management as determinant of patch selection by foraging herbivores in western Serengeti, Tanzania
Although the use of fire as a management tool has increased during the past decades in East African savannas, there is insufficient knowledge about herbivores’ utilization of areas with different fire history. We therefore examined large mammal herbivores’ preference for patches that differed in fire history to test whether herbivores would non-randomly select patches according […]
Why do some African thorn trees (Acacia spp.) have a flat-top: a grazer-plant mutualism hypothesis?
The quintessential African savanna tree is the flat-topped Acacia. However, the reason for the architecture occurring in sparse-canopied small-leafed tree species from well-lit, often mesic, environments is unclear. Brown (1960) suggested that it reduced feeding by the distinctly African herbivore, the giraffe. Escaping recaptured herbivore and/or fire damage is crucial for palatable savanna trees such […]
Food preferences of giraffe in Transvaal Lowveld Mopane Woodland
The trees and shrubs browsed by giraffe in Transvaal Lowveld Mopane Woodland were recorded by direct observation. A preference rating for the different plant species was calculated by correlating these data with the percentage frequency occurrence of the plants in the field. Giraffe were found to clearly prefer some species and avoid others. The reason […]