Biology subjects

Fennessy, J.

Publications and source records attributed to Fennessy, J..

5 recordsLinked to original sources

bioRxiv2026

Comparative anatomy of the giraffe distal limb

Giraffe in human care are known to experience significant clinical issues related to their feet. To characterize normal foot anatomy, we analyzed six sets of front and hind feet from wild Angolan giraffe and one calf in human care. We used computed tomography, three-dimensional reconstruction, sagittal sections, and gross dissection to acquire as much gross anatomical detail as possible. Significant anatomical findings include the deep digital flexor tendon that is very gracile as it crosses the fetlock and proximal phalanges but widens significantly before inserting onto the entire palmar/plantar surface of the distal phalanx. Significant subcutaneous abaxial veins were noted at the level of the fetlock in both front and hind feet. The digital cushion was found to be a complex structure consisting of two distinct regions, one underneath the distal phalanx, characterized by multiple transversely oriented small adipose compartments separated by dense connective tissue septa, and a significantly larger portion within the heel bulb, consisting of two sagittally oriented fat bodies encased in a dense connective tissue capsule and divided by a thick septum. The proportion of adipose tissue volume in the heel bulbs compared to the distal phalanx decreases with age. The thickness of the sole was found to be much greater than that of the wall and the sole appears to be the major weight supporting structure of the foot. In particular, the heel is greatly expanded in giraffe relative to other ruminants and was found to consist of softer material than the rest of the sole. Data presented here provide an overview of normal giraffe foot anatomy, which can be compared with data from giraffe in human care to better understand, guide treatment and prevention of abnormal anatomical conditions.

zoology↗

bioRxiv2024

Random subsamples of animal populations can reveal intrinsic differences in sociality with key implications in ecology, conservation and disease transmission

Animal populations are under mounting stress from the dual threats of climate change and rapid global human population growth, raising significant concerns about declining wildlife and the rising risk of zoonotic diseases. In many species, social interactions can be a highly plastic suite of behaviours that are responsive to these disturbances and are consequential to other processes like disease transmission and population dynamics. Studying social interactions can be challenging in that researchers often rely on wildlife population subsamples due to practical constraints and costs, which can introduce biases in the reliability of social network metrics. We investigated the extent to which subsamples can depict intrinsic characteristics of wildlife populations using data from three distinct species: peri-urban fallow deer, Alpine ibex and Angolan giraffe. We showed that random subsamples of these populations could still reveal differences in their social behaviour, indicating that, as long as researchers have a reliable estimate of population size, subsampling animal populations can be an effective and precise method to infer their sociality and offer valuable empirical data for management, conservation and zoonotic disease ecology. Furthermore, we demonstrate that non-random sampling, influenced for instance by animal personality and related trappability, can introduce significant biases in social network estimates. These findings underscore the importance of accounting for sampling biases in social network analysis and offer a robust framework for using partial networks in ecological studies and conservation management.

ecology↗

bioRxiv2023

Genomic analysis reveals limited hybridization among three giraffe species in Kenya

BackgroundIn the speciation continuum the strength of reproductive isolation varies, and species boundaries are blurred by gene flow. Interbreeding among giraffe (Giraffa spp.) in captivity is known and anecdotal reports of natural hybrids exist. In Kenya, Nubian (G. camelopardalis camelopardalis), reticulated (G. reticulata), and Masai giraffe sensu stricto (G. tippelskirchi tippelskirchi) are parapatric, and thus the country might be a melting pot for these taxa. We analyzed 128 genomes of wild giraffe, 113 newly sequenced, representing these three taxa. ResultsWe found varying levels of Nubian ancestry in 13 reticulated giraffe sampled across the Laikipia Plateau most likely reflecting historical gene flow between these two lineages. Although comparatively weaker signs of ancestral gene flow and potential mitochondrial introgression from reticulated into Masai giraffe were also detected, estimated admixture levels between these two lineages are minimal. Importantly, contemporary gene flow between East African giraffe lineages was not statistically significant. Effective population sizes have declined since the Late Pleistocene, more severely for Nubian and reticulated giraffe. ConclusionsDespite historically hybridizing, these three giraffe lineages have maintained their overall genomic integrity suggesting effective reproductive isolation, consistent with the previous classification of giraffe into four species.

evolutionary biology↗

bioRxiv2023

The search behavior of terrestrial mammals

Animals moving through landscapes need to strike a balance between finding sufficient resources to grow and reproduce while minimizing encounters with predators 1,2. Because encounter rates are determined by the average distance over which directed motion persists 1,3-5, this trade-off should be apparent in individuals movement. Using GPS data from 1,396 individuals across 62 species of terrestrial mammals, we show how predators maintained directed motion ~7 times longer than for similarly-sized prey, revealing how prey species must trade off search efficiency against predator encounter rates. Individual search strategies were also modulated by resource abundance, with prey species forced to risk higher predator encounter rates when resources were scarce. These findings highlight the interplay between encounter rates and resource availability in shaping broad patterns mammalian movement strategies.

ecology↗

bioRxiv2018

Limited Introgression Supports Division of Giraffe into Four Species

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.

ecology↗