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André Ganswindt - One of the best experts on this subject based on the ideXlab platform.
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Androgen changes and flexible rutting behaviour in male Giraffes.
Biology Letters, 2013Co-Authors: Peter A Seeber, Patrick Duncan, Hervé Fritz, André GanswindtAbstract:The social organization of Giraffes (Giraffa camelopardalis) imposes a high-cost reproductive strategy on bulls, which adopt a 'roving male' tactic. Our observations on wild Giraffes confirm that bulls indeed have unsynchronized rut-like periods, not unlike another tropical megaherbivore, the elephant, but on a much shorter timescale. We found profound changes in male sexual and social activities at the scale of about two weeks. This so far undescribed rutting behaviour is closely correlated with changes in androgen concentrations and appears to be driven by them. The short time scale of the changes in sexual and social activity may explain why dominance and reproductive status in male Giraffe in the field seem to be unstable.
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Behavioural inventory of the Giraffe (Giraffa camelopardalis)
BMC Research Notes, 2012Co-Authors: Peter A Seeber, Isabelle Ciofolo, André GanswindtAbstract:Numerous factors like continuous habitat reduction or fragmentation for free-ranging Giraffes (Giraffa camelopardalis) as well as e.g. suboptimal housing conditions for animals in captivity might lead to behavioural alterations as part of the overall adaptation process to the changing living conditions. In order to facilitate current and future studies on Giraffe behaviour, a comprehensive ethogram was compiled based on existing literature, as well as observations on Giraffes in the wild (Hwange National Park, Zimbabwe; Entabeni Game Reserve, South Africa), and in captivity (National Zoological Gardens of South Africa, Pretoria). The resulting ethogram lists 65 different behavioural patterns, which were described and grouped into seven categories: General activities, Abnormal repetitive behaviours, General interactions, Bull-Cow behaviour, Bull-Bull behaviour, Cow-Bull behaviour, Maternal behaviours, and Interactions by calves. The behaviours were further described regarding a presumed purpose, particularly with respect to social interactions and sexual behaviour. Contradictory descriptions from previous studies were considered and discussed in comparison with our own observations. This ethogram provides a basis for current and future studies by suggesting a terminology which can be used for harmonizing behavioural observations, thus helping to facilitate comparability of future results. Subsequently, a better understanding of the behavioural ecology of Giraffes in the wild as well as in captivity could aid future conservation efforts.
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grazing behaviour of the Giraffe in hwange national park zimbabwe
African Journal of Ecology, 2012Co-Authors: Peter A Seeber, Patrick Duncan, André Ganswindt, Honestly T NdlovuAbstract:The Giraffe (Giraffa camelopardalis) is usually described as an exclusive browser, feeding only on shrubs and trees, preferrably between 2 and 5 m above ground (Lamprey, 1963; McNaughton & Georgiadis, 1986; Ciofolo & Le Pendu, 2002). Although browsing seems to be an easier form of feeding for Giraffes in terms of accessibility and vigilance (Young & Isbell, 1991), a few studies mention that the Giraffe also ‘very occasionally’ feeds on grass (Pienaar, 1963; Du Toit, 2005). To be able to graze, a Giraffe has to adopt the typical ‘drinking position’, where the forelegs are splayed out laterally, and sometimes the carpal joints are also flexed. In this position, the animals are particularly vulnerable to predators (Periquet et al., 2010). In this note, we show that grazing, although not a core activity, is a recurrent event in a nutrient-poor environment such as Hwange National Park and suggest a possible function.
Axel Janke - One of the best experts on this subject based on the ideXlab platform.
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Species assignment and conservation genetics of Giraffe in the Republic of Malawi
Conservation Genetics, 2019Co-Authors: Sven Winter, Julian Fennessy, Raphael T. F. Coimbra, Anna Bronec, Craig Hay, Amanda L. Salb, Axel JankeAbstract:Historically, Giraffe have been translocated across Africa to supplement extant populations, reintroduce extinct populations or to establish new populations, often for conservation and tourism. Such faunal relocations were often carried out disregarding taxonomic affiliation. Today, the small Giraffe populations in the Republic of Malawi are assumed to consist of South African Giraffe (Giraffa giraffa giraffa), which have likely descended from five individuals translocated from Imire Game Park (Zimbabwe) to Nyala Game Park (Malawi) in 1993. However, during the last 25 years, unknown additional translocations, migrations or unrecognized local populations of potential Masai Giraffe (Giraffa tippelskirchi) in Malawi may have resulted in introgressive hybridization. Thus, the current taxonomic affiliation for Malawi’s Giraffe is uncertain, calling for a genetic assessment to implement further management. We analyzed mitochondrial sequences and nuclear introns for 14 individuals, representing approximately half of the known Malawian population, to genetically determine the (sub)species of Giraffe that occur in the Republic of Malawi by comparison with a comprehensive Giraffa dataset. Additionally, we genotyped individuals at ten microsatellite loci to determine the level of inbreeding and potential introgression. All data identify individuals unambiguously as South African Giraffe, although two individuals shared a single nuclear allele with Masai Giraffe. The low microsatellite genetic variability suggests high inbreeding in the current population. Thus, supplementing Malawi’s Giraffe populations with G. g. giraffa will prevent further loss of their genetic diversity and avoid inbreeding depression.
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Matrilineal population structure and distribution of the Angolan Giraffe in the Namib desert and beyond
Ecological Genetics and Genomics, 2018Co-Authors: Sven Winter, Julian Fennessy, Stephanie Fennessy, Axel JankeAbstract:Abstract The distribution maps of Giraffe ( Giraffa ) subspecies in southern Africa are based on historical assumptions, yet some populations have likely been misidentified, hindering effective conservation efforts. Particularly, the populations in Zimbabwe are poorly studied, and translocations, such as the 1991 movement of Giraffe from Namibia's Etosha National Park to mitigate the human-induced decline of Namibia's desert-dwelling Giraffe in the lower Hoanib and Hoarusib Rivers, was concluded without consideration of genotype. Mitochondrial DNA sequence analyses from cytochrome b and control region revealed that instead of the South African Giraffe subspecies ( G. giraffa giraffa ), the Angolan Giraffe ( G. g. angolensis ) occurs in southern Zimbabwe's Bubye Valley Conservancy. Furthermore, Namibia's desert-dwelling Giraffe and those from Etosha National Park form distinct matrilineal lineages within the Angolan Giraffe subspecies clade. Thus, despite the translocation and proximity of the Etosha National Park, the Etosha Giraffe genotype has not spread amongst the desert-dwelling Giraffe. Use of mutation rate estimates indicates that there has been no matrilineal exchange between Etosha and the desert-dwelling Giraffe for ca. 40,000 years. While philopatry could produce distinct mitochondrial lineages, the short geographical distance and long time involved, makes it more likely that the Etosha Giraffe cannot successfully compete with a putatively better adapted desert-dwelling Giraffe. The analyses also show that the distribution of the Angolan Giraffe extends further eastwards than expected. These findings provide important implications for Giraffe conservation, and translocation in particular, which may not always be an effective means of improving genetic diversity.
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Limited Introgression Supports Division of Giraffe into Four Species
bioRxiv, 2018Co-Authors: Sven Winter, Julian Fennessy, Axel JankeAbstract:All Giraffe (Giraffa) were previously assigned to a single species (G. camelopardalis) and nine subspecies. However, multi-locus analyses of all subspecies have shown that there are four genetically distinct clades and suggest four Giraffe species. This conclusion might not be fully accepted due to limited data and lack of explicit gene flow analyses. Here we present an extended study based on 21 independent nuclear loci from 137 individuals. Explicit gene flow analyses identify less than one migrant per generation, including between the closely related northern and reticulated Giraffe. Thus, gene flow analyses and population genetics of the extended dataset confirm four genetically distinct Giraffe clades and support four independent Giraffe species. The new findings call for a revision of the IUCN classification of Giraffe taxonomy. Three of the four species are threatened with extinction, mostly occurring in politically unstable regions, and as such, require the highest conservation support possible.
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Multi-locus Analyses Reveal Four Giraffe Species Instead of One.
Current Biology, 2016Co-Authors: Julian Fennessy, Tobias Bidon, Friederike Reuss, Vikas Kumar, Paul W. Elkan, Maria A. Nilsson, Melita Vamberger, Uwe Fritz, Axel JankeAbstract:Traditionally, one Giraffe species and up to eleven subspecies have been recognized [1]; however, nine subspecies are commonly accepted [2]. Even after a century of research, the distinctness of each Giraffe subspecies remains unclear, and the genetic variation across their distribution range has been incompletely explored. Recent genetic studies on mtDNA have shown reciprocal monophyly of the matrilines among seven of the nine assumed subspecies [3, 4]. Moreover, until now, genetic analyses have not been applied to biparentally inherited sequence data and did not include data from all nine Giraffe subspecies. We sampled natural Giraffe populations from across their range in Africa, and for the first time individuals from the nominate subspecies, the Nubian Giraffe, Giraffa camelopardalis camelopardalis Linnaeus 1758 [5], were included in a genetic analysis. Coalescence-based multi-locus and population genetic analyses identify at least four separate and monophyletic clades, which should be recognized as four distinct Giraffe species under the genetic isolation criterion. Analyses of 190 individuals from maternal and biparental markers support these findings and further suggest subsuming Rothschild's Giraffe into the Nubian Giraffe, as well as Thornicroft's Giraffe into the Masai Giraffe [6]. A Giraffe survey genome produced valuable data from microsatellites, mobile genetic elements, and accurate divergence time estimates. Our findings provide the most inclusive analysis of Giraffe relationships to date and show that their genetic complexity has been underestimated, highlighting the need for greater conservation efforts for the world's tallest mammal.
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mitochondrial sequences reveal a clear separation between angolan and south african Giraffe along a cryptic rift valley
BMC Evolutionary Biology, 2014Co-Authors: Friederike Bock, Francois Deacon, Julian Fennessy, Andy Tutchings, Tobias Bidon, Andri Marais, Axel JankeAbstract:Background The current taxonomy of the African Giraffe (Giraffa camelopardalis) is primarily based on pelage pattern and geographic distribution, and nine subspecies are currently recognized. Although genetic studies have been conducted, their resolution is low, mainly due to limited sampling. Detailed knowledge about the genetic variation and phylogeography of the South African Giraffe (G. c. giraffa) and the Angolan Giraffe (G. c. angolensis) is lacking. We investigate genetic variation among Giraffe matrilines by increased sampling, with a focus on Giraffe key areas in southern Africa.
Fred B. Bercovitch - One of the best experts on this subject based on the ideXlab platform.
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How many species of Giraffe are there
Current Biology, 2017Co-Authors: Fred B. Bercovitch, Philip S. M. Berry, Anne Innis Dagg, Francois Deacon, John Doherty, Derek E. Lee, Frédéric Mineur, Zoe Muller, Rob Ogden, Russell SeymourAbstract:In a recent paper in Current Biology, Fennessy and colleagues [1] conclude that there are four species of Giraffe and that their numbers are declining in Africa. Giraffes (Giraffa camelopardalis) are presently classified as one species, with nine subspecies, which are considered 'Vulnerable' on the IUCN Red List [2]. The present consensus of one species divided into nine subspecies has previously been questioned (Supplemental information), and Fennessy and colleagues [1] provide another viewpoint on Giraffe taxonomy. The fundamental reason for different taxonomic interpretations is that they are based upon different datasets that adopt different statistical techniques and follow different criteria for nomenclature.
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Gazing at a Giraffe gyroscope: where are we going?
African Journal of Ecology, 2015Co-Authors: Fred B. Bercovitch, Francois DeaconAbstract:Giraffe are popular animals to watch while on wildlife safaris, and feature prominently in zoos, advertisements, toys and cartoons. Yet, until recently, few field studies have focused on Giraffe. We introduce this Giraffe topic issue with a review essay that explores five primary questions: How many (sub) species of Giraffe exist? What are the dynamics of Giraffe herds? How do Giraffe communicate? What is the role of sexual selection in Giraffe reproduction? How many Giraffe reside in Africa? A confluence of causes has produced drastic declines in Giraffe population numbers in Africa, and we conclude that guiding Giraffe conservation plans depends upon evaluation of the five key quandaries that we pose. Resume Les girafes sont des animaux que les touristes aiment observer lors des safaris et elles tiennent une place importante dans les zoos, les publicites, les jouets et les dessins animes. Pourtant, jusqu'il y a peu, seules quelques etudes de terrain s’etaient interessees a la girafe. Nous commencons cette publication sur les girafes par une analyse qui explore cinq questions fondamentales: Combien y a-t-il d'especes (de sous-especes) de girafes? Quelle est la dynamique des groupes de girafes? Comment les girafes communiquent-elles? Quel est le role de la selection sexuelle dans la reproduction des girafes? Combien y a-t-il de girafes en Afrique? Une confluence de causes a entraine un declin drastique des populations de girafes en Afrique, et nous concluons que l'orientation des plans de conservation des girafes depend de l’evaluation des cinq questions que nous soulevons.
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age proximity influences herd composition in wild Giraffe
Journal of Zoology, 2013Co-Authors: Fred B. Bercovitch, P S M BerryAbstract:In many mammalian species, animals form subunits within larger groups that are often associated with kinship and/or age proximity. Kinship mediates fission/fusion social dynamics of Giraffe herds, but the role of age proximity has been unexamined. Here, we analyze 34 years of data from a population of Thornicroft's Giraffe, Giraffa camelopardalis thornicroftii, living in Zambia in order to assess the extent to which age proximity influences herd composition. We show for the first time that calves born into the same cohort have stronger social associations than calves born into different age cohorts, and that the strength of their association is independent of the strength of maternal associations. Duration of time co-resident in the population did not influence the strength of social associations. Mothers and adult daughters have significantly stronger social associations than do unrelated adult females. We suggest that Giraffe have evolved mechanisms for fostering the formation of social associations with similar aged non-kin. Giraffes live in a complex society incorporating both kinship and age proximity as factors modulating the formation of social associations that underlie the fission/fusion dynamics of their flexible herd structure.
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herd composition kinship and fission fusion social dynamics among wild Giraffe
African Journal of Ecology, 2013Co-Authors: Fred B. Bercovitch, Philip S. M. BerryAbstract:A variety of social systems have evolved as a consequence of competition and cooperation among individuals. Giraffe (Giraffa camelopardalis sp.) societies are an anomaly because the dearth of long-term data has produced two polar perspectives: a loose amalgamation of non-bonded individuals that sometimes coalesce into a herd and a structured social system with a fission–fusion process modifying herd composition within a community. We analysed 34 years of data collected from a population of Thornicroft's Giraffe (G. c. thornicrofti, Lydekker 1911) residing in South Luangwa, Zambia, to establish the nature of Giraffe society. Our sample consisted of 52 individually recognized animals. We found that Giraffe herd composition is based upon long-term social associations that often reflect kinship, with close relatives significantly more likely than non-relatives to establish herds. Mother/offspring dyads had the strongest associations, which persisted for years. Giraffe live in a complex society characterized by marked flexibility in herd size, with about 25% of the variance in herd composition owing to kinship and sex. We suggest that Giraffe herds share many characteristics of fission–fusion social systems and propose that sophisticated communication systems are a crucial component regulating subgroup dynamics.
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ecological determinants of herd size in the thornicroft s Giraffe of zambia
African Journal of Ecology, 2010Co-Authors: Fred B. Bercovitch, Philip S. M. BerryAbstract:Ecological factors have a pervasive impact on animal population sizes and the structure of their social systems. In a number of ungulate species, predator pressure exerts a major influence on group size. Given that Giraffe (Giraffa camelopardalis) live in an extremely flexible social system, and that breeding is nonseasonal, they are an ideal species for examining how ecological variables contribute to fluctuations in herd size. We present an analysis of 34 years of data on a population of Thornicroft’s Giraffe (G. c. thornicrofti Lydekker 1911) that reveal how herd size changes with season and habitat. Sex differences in herd size were apparent, with bulls often travelling as singletons, whereas cows were generally observed with conspecifics. Herds were larger during the wet than dry season, but herd size changed in a parallel fashion across habitats. Giraffe herds were smaller in woodland and thicket areas than in open habitats, regardless of season. We suggest that the regular fluctuations in herd size among Giraffe indicate a fission/fusion social system embedded within a larger social community. We conclude that changes in herd size among Giraffe reflect a dynamic process regulated by individuals adjusting the number of associates based upon an interaction of foraging, reproductive, social and antipredator strategies. Resume Les facteurs ecologiques ont un effet generalise sur la taille des populations animales et sur la structure de leurs systemes sociaux. Chez un certain nombre d’especes d’ongules, la pression des predateurs exerce une influence majeure sur la taille des groupes. Etant donne que la girafe Giraffa camelopardalis vit dans un systeme social extremement flexible, et que la reproduction n’y est pas saisonniere, c’est une espece ideale pour examiner comment des variables ecologiques contribuent aux fluctuations de la taille de la harde. Nous presentons une analyse couvrant 34 annees de donnees sur une population de girafes de Thornicroft, G. c. thornicrofti Lyddeker 1911, qui revele comment la taille de la harde change avec les saisons et l’habitat. La difference des sexes dans la taille des hardes etait visible, les mâles voyageant souvent en solitaires alors que les femelles etaient generalement observees avec des congeneres. Les hardes etaient plus grandes en saison des pluies qu’en saison seche, mais la taille des hardes changeait, dans le meme temps, selon les habitats. Les hardes de girafes etaient plus petites en foret et dans les zones arbustives que dans les habitats ouverts, quelle que soit la saison. Nous suggerons que, chez les girafes, la taille des hardes indique une fission/fusion du systeme social ancre dans une communaute sociale plus large. Nous concluons que les changements de taille de hardes chez les girafes refletent un processus dynamique regule par des individus qui ajustent le nombre de leurs associes selon une interaction des strategies alimentaires, reproductives, sociales et defensives contre les predateurs.
Cheryl Mabika - One of the best experts on this subject based on the ideXlab platform.
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The two oxpecker species reveal the role of movement rates and foraging intensity in species coexistence
Biology Letters, 2019Co-Authors: Guillaume Péron, Roxanne Gagnon, Christophe Bonenfant, Cheryl MabikaAbstract:The two Buphagus oxpecker species are specialized passerines that forage for ticks and other food particles on the body of ungulates in the African savan-nahs. One of their intriguing features is their ability to coexist despite sharing the same, specialized diet. Using co-occurrence data (photographs of Giraffes with oxpeckers on them) and approximate Bayesian computing, we demonstrate that yellow-billed oxpeckers changed host faster than red-billed oxpeckers and appeared to displace red-billed oxpeckers from preferred Giraffe body parts. Conversely, red-billed oxpeckers exhibited a fuller use of each host and displaced yellow-billed oxpeckers from distal Giraffe body parts. These findings highlight that the partition of Giraffe hosts in two separate niches was only part of the coexistence story in this species pair. More precisely, the oxpeckers shared the resource by exploiting it at different rates. They engaged in different trade-offs between giving-up density , patch discovery rate and competitor displacement ability. They illustrate the importance of the time frame of interactions.
Christophe Bonenfant - One of the best experts on this subject based on the ideXlab platform.
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Distribution and density of oxpeckers on Giraffes in Hwange National Park, Zimbabwe
bioRxiv, 2019Co-Authors: Roxanne Gagnon, Cheryl T. Mabika, Christophe BonenfantAbstract:Abstract Oxpeckers (Buphagus sp.) are two sub-Saharan bird species closely associated to large mammals, which they use as hosts for foraging. The comparison of opxecker abundance among large mammalian species has been repeatedly investigated in many areas of Southern Africa, and Giraffe (Giraffa camelopardalis) is a strongly favoured hosts. The foraging behaviour of oxpeckers at the individual and the body levels of Giraffes remains little studied, however. By comparing the distribution of oxpeckers among and within individual Giraffes, one may infer on the foraging behaviour of birds. Here, we counted every oxpeckers on Giraffe’s body from pictures and assessed the detection probability of birds on their host. We first tested whether oxpeckers distributed themselves at random or aggregated on individual Giraffes. Then we explored the distribution of oxpeckers on pre-defined zones on the Giraffe body from which tested the prediction that birds would be preferentially found on the host’s body parts providing birds with the greatest amount of ticks. Oxpeckers displayed a strong aggregation behaviour with few hosts carrying many birds while many carried a limited number or no birds, a pattern that differed between sexes. Oxpeckers were not uniformly distributed on the Giraffe’s body and were mostly found on the mane and back, where the density of ticks is presumably the highest. The high aggregation level of birds we report is typical of parasitic species and would hence suggest oxpeckers behave more like parasites rather than a mutualistic species with Giraffes. Alternatively this particular oxpecker distribution may mirror the distribution of ticks among hosts. Abundance of ticks appears indeed as a major driver of the oxpecker foraging behaviour because, as we predicted, birds were most numerous on the Giraffes’ body part where ectoparasite density is expected to be the greatest (mane and back up to the tail insertion). From an ecological point of view, the oxpecker–large herbivores system proves to be highly relevant and useful for the study of host-parasite dynamics.
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The two oxpecker species reveal the role of movement rates and foraging intensity in species coexistence
Biology Letters, 2019Co-Authors: Guillaume Péron, Roxanne Gagnon, Christophe Bonenfant, Cheryl MabikaAbstract:The two Buphagus oxpecker species are specialized passerines that forage for ticks and other food particles on the body of ungulates in the African savan-nahs. One of their intriguing features is their ability to coexist despite sharing the same, specialized diet. Using co-occurrence data (photographs of Giraffes with oxpeckers on them) and approximate Bayesian computing, we demonstrate that yellow-billed oxpeckers changed host faster than red-billed oxpeckers and appeared to displace red-billed oxpeckers from preferred Giraffe body parts. Conversely, red-billed oxpeckers exhibited a fuller use of each host and displaced yellow-billed oxpeckers from distal Giraffe body parts. These findings highlight that the partition of Giraffe hosts in two separate niches was only part of the coexistence story in this species pair. More precisely, the oxpeckers shared the resource by exploiting it at different rates. They engaged in different trade-offs between giving-up density , patch discovery rate and competitor displacement ability. They illustrate the importance of the time frame of interactions.