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Basel, Switzerland

Sommer V.,University College London | Lowe A.,University College London | Dietrich T.,Basel Zoo
Animal Cognition | Year: 2016

Carrying food to water and either dunking or manipulating it before consumption has been observed in various taxa including birds, racoons and primates. Some animals seem to be simply moistening their food. However, true washing aims to remove unpleasant surface substrates such as grit and sand and requires a distinction between items that do and do not need cleaning as well as deliberate transportation of food to a water source. We provide the first evidence for food washing in suids, based on an incidental observation with follow-up experiments on European wild boar (Sus scrofa) kept at Basel Zoo, Switzerland. Here, all adult pigs and some juveniles of a newly formed group carried apple halves soiled with sand to the edge of a creek running through their enclosure where they put the fruits in the water and pushed them to and fro with their snouts before eating. Clean apple halves were never washed. This indicates that pigs can discriminate between soiled and unsoiled foods and that they are able to delay gratification for long enough to transport and wash the items. However, we were unable to ascertain to which degree individual and/or social learning brought this behaviour about. © 2015, Springer-Verlag Berlin Heidelberg.

Pluhacek J.,Institute of Animal Science | Steck B.L.,Basel Zoo
Ethology | Year: 2015

Social and reproductive systems remain among the main predictors affecting mammalian birth sex ratio. The two extant hippopotamus species differ in their social and reproductive systems. While common hippopotamus (Hippopotamus amphibius) form herds and tend to be polygynous, solitary living pygmy hippopotamus (Choeropsis liberiensis) are promiscuous. Although it is one of the most studied topics, only few empirical studies using large sample sizes have reported distorted birth sex ratio. We examined the birth sex ratio in both hippopotamus species using international studbooks including large data sets exceeding a thousand individuals (1138 for common hippopotamus and 1161 for pygmy ones). In both species, the birth sex ratio differed from 1:1. Whereas more males than females were recorded in common hippopotamus (53.9% males), the opposite was found in pygmy hippopotamus (41.5% males). We also found that the birth sex ratio was affected by individual dams in common hippopotamus, and by individual sires in pygmy hippopotamus. The most plausible explanation for differentially skewed birth sex ratios in both species may be related to differences in social and reproductive systems. Whereas the polygynous, sexually dimorphic common hippopotamus biased the birth sex ratio towards males, the promiscuous and sexually monomorphic pygmy hippopotamus skewed the sex ratio in favour of females. Our results are in line with recent studies showing that not only manipulation by the mother (in common hippopotamus), but also by the father (in pygmy hippopotamus), may be responsible for the birth sex ratio in different species. © 2015 Blackwell Verlag GmbH.

Bock F.,Biodiversity and Climate Research Center | Gallus S.,Biodiversity and Climate Research Center | Janke A.,Biodiversity and Climate Research Center | Janke A.,Goethe University Frankfurt | And 4 more authors.
Zoo Biology | Year: 2014

The lesser kudu (Tragelaphus imberbis) is a spiral-horned antelope native to northeastern Africa. Individuals kept in zoological gardens are suspected to be highly inbred due to few founder individuals and a small breeding stock. A morphological study suggested two distinct subspecies of the lesser kudu. However, subspecies designation and population structure in zoological gardens has not been analyzed using molecular markers. We analyzed one mitochondrial marker and two nuclear intron loci (total: 2,239 nucleotides) in 52 lesser kudu individuals. Of these, 48 individuals were bred in captivity and sampled from seven different zoos. The four remaining individuals were recently captured in Somalia and are currently held in the Maktoum zoo. Maternally inherited mitochondrial sequences indicate substantial amounts of genetic variation in the zoo populations, while the biparentally inherited intron sequences are, as expected, less variable. The analyzed individuals show 10 mitochondrial haplotypes with a maximal distance of 10 mutational steps. No prominent subspecies structure is detectable in this study. For further studies of the lesser kudu population genetics, we present microsatellite markers from a low-coverage genome survey using 454 sequencing technology. Zoo Biol. 33:440-445, 2014. © 2014 Wiley Periodicals, Inc.

Deville A.-S.,CNRS Center of Evolutionary and Functional Ecology | Gremillet D.,CNRS Center of Evolutionary and Functional Ecology | Gremillet D.,University of Cape Town | Gauthier-Clerc M.,University of Franche Comte | And 3 more authors.
Ecology and Evolution | Year: 2013

Accurate knowledge of the functional response of predators to prey density is essential for understanding food web dynamics, to parameterize mechanistic models of animal responses to environmental change, and for designing appropriate conservation measures. Greater flamingos (Phoenicopterus roseus), a flagship species of Mediterranean wetlands, primarily feed on Artemias (Artemia spp.) in commercial salt pans, an industry which may collapse for economic reasons. Flamingos also feed on alternative prey such as Chironomid larvae (e.g., Chironomid spp.) and rice seeds (Oryza sativa). However, the profitability of these food items for flamingos remains unknown. We determined the functional responses of flamingos feeding on Artemias, Chironomids, or rice. Experiments were conducted on 11 captive flamingos. For each food item, we offered different ranges of food densities, up to 13 times natural abundance. Video footage allowed estimating intake rates. Contrary to theoretical predictions for filter feeders, intake rates did not increase linearly with increasing food density (type I). Intake rates rather increased asymptotically with increasing food density (type II) or followed a sigmoid shape (type III). Hence, flamingos were not able to ingest food in direct proportion to their abundance, possibly because of unique bill structure resulting in limited filtering capabilities. Overall, flamingos foraged more efficiently on Artemias. When feeding on Chironomids, birds had lower instantaneous rates of food discovery and required more time to extract food from the sediment and ingest it, than when filtering Artemias from the water column. However, feeding on rice was energetically more profitable for flamingos than feeding on Artemias or Chironomids, explaining their attraction for rice fields. Crucially, we found that food densities required for flamingos to reach asymptotic intake rates are rarely met under natural conditions. This allows us to predict an immediate negative effect of any decrease in prey density upon flamingo foraging performance. © 2013 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

Wyss F.,University of Bern | Wyss F.,University of Zurich | Wenker C.,Basel Zoo | Hoby S.,Basel Zoo | And 4 more authors.
Animal Welfare | Year: 2014

Pododermatitis is a worldwide health and animal welfare problem in captive flamingos (Phoenicopteridae). Since sub-optimal substrate or flooring has been described as a factor in the development of pododermatitis in poultry and raptors, it is also suspected to play a role in flamingo foot health. Small groups of flamingos were separated from the main group in an indoor enclosure with artificial grass carpet and, in earlier years, concrete flooring, with additional fine granular sand in the water basin for the study year. Feet were evaluated before and after the separation. Judged subjectively, foot lesions had shown a general increase in the indoor enclosure in earlier years. In contrast, lesion severity and prevalence, scored in accordance with a standardised protocol, decreased when fine granular sand was provided. Since flamingos were observed mostly standing on sand and as this represented the major differentiating factor between years, it is concluded that fine granular sand is a favourable substrate to maintain, and one that may even lead to an improvement in flamingo foot health. © 2014 Universities Federation for Animal Welfare.

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