scholarly journals Co‐occurrence of high densities of brown hyena and spotted hyena in central Tuli, Botswana

2021 ◽  
Author(s):  
S. Vissia ◽  
R. Wadhwa ◽  
F. Langevelde
Keyword(s):  
Spotted Hyena ◽  
Brown Hyena

scholarly journals Phylogenetic Comparisons Implicate Sex Hormone-Binding Globulin in “Masculinization” of the Female Spotted Hyena (Crocuta crocuta)

Endocrinology ◽  
2012 ◽  
Vol 153 (3) ◽  
pp. 1435-1443 ◽  
Author(s):  
Geoffrey L. Hammond ◽  
Solange Miguel-Queralt ◽  
Tamer M. Yalcinkaya ◽  
Caroline Underhill ◽  
Ned J. Place ◽  
...  
Keyword(s):  
Social Dominance ◽  
External Genitalia ◽  
Biologically Active ◽  
Sex Hormone Binding Globulin ◽  
Spotted Hyena ◽  
Secretion Signal ◽  
High Affinity ◽  
Spotted Hyenas ◽  
Steroid Binding ◽  
Brown Hyena

Exposures to sex steroids during fetal development are thought to contribute to the unique urogenital anatomy and social dominance of the female spotted hyena: overt phenotypes not shared by other hyenids (i.e. striped hyena, brown hyena, and aardwolf). Because both androgens and estrogens influence development of genitalia and behavior, and because plasma SHBG regulates their access to tissues, we compared the Shbg gene sequences, structures, and steroid-binding properties in the four extant hyenids. We found the hyenid Shbg genes (>95% identical) and mature protein sequences (98% identical) are highly conserved. As in other mammals, the hyenid SHBG all bind 5α-dihydrotestosterone with high affinity (Kd = 0.62–1.47 nm), but they also bind estrone and dehydroepiandrosterone with similarly high affinity, and this unusual property was attributed to specific amino acids within their SHBG steroid-binding sites. Phylogenetic comparisons also indicated that the spotted hyena SHBG precursor uniquely lacks two leucine residues and has a L15W substitution within its secretion signal polypeptide, the reduced size and hydrophobicity of which markedly decreases the production of SHBG and may therefore explain why serum SHBG concentrations in male and female spotted hyenas are approximately five times lower than in other hyenids. This is important because low plasma SHBG concentrations in spotted hyenas will increase exposure to biologically active androgens and estrogen as well as to their precursors (dehydroepiandrosterone and estrone), which may contribute to the masculinized external genitalia of female spotted hyenas and to female social dominance over males.

Contribution of enhanced DWT and non-negative structured sparse representation for image super resolution: A performance analysis

2020 ◽  
Vol 18 (06) ◽  
pp. 2050049
Author(s):  
A. Valli Bhasha ◽  
B. D. Venkatramana Reddy
Keyword(s):  
Sparse Representation ◽  
Hyperspectral Image ◽  
Super Resolution ◽  
Image Resolution ◽  
Discrete Wavelet ◽  
Spotted Hyena ◽  
Resolution Model ◽  
Deep Cnn ◽  
Image Super Resolution ◽  
Two Phases

The image super-resolution methods with deep learning using Convolutional Neural Network (CNN) have been producing admirable advancements. The proposed image resolution model involves the following two main analyses: (i) analysis using Adaptive Discrete Wavelet Transform (ADWT) with Deep CNN and (ii) analysis using Non-negative Structured Sparse Representation (NSSR). The technique termed as NSSR is used to recover the high-resolution (HR) images from the low-resolution (LR) images. The experimental evaluation involves two phases: Training and Testing. In the training phase, the information regarding the residual images of the dataset are trained using the optimized Deep CNN. On the other hand, the testing phase helps to generate the super resolution image using the HR wavelet subbands (HRSB) and residual images. As the main novelty, the filter coefficients of DWT are optimized by the hybrid Fire Fly-based Spotted Hyena Optimization (FF-SHO) to develop ADWT. Finally, a valuable performance evaluation on the two benchmark hyperspectral image datasets confirms the effectiveness of the proposed model over the existing algorithms.

Urogenital system of the spotted hyena (Crocuta crocuta Erxleben): A functional histological study

2003 ◽  
Vol 256 (2) ◽  
pp. 205-218 ◽  
Author(s):  
Gerald R. Cunha ◽  
Yuzhuo Wang ◽  
Ned J. Place ◽  
Wenhui Liu ◽  
Larry Baskin ◽  
...  
Keyword(s):  
Histological Study ◽  
Crocuta Crocuta ◽  
Spotted Hyena ◽  
Urogenital System

scholarly journals Ecological specialisation and evolutionary reticulation in extant Hyaenidae

2020 ◽  
Author(s):  
M V Westbury ◽  
Diana Le Duc ◽  
David A. Duchêne ◽  
Arunkumar Krishnan ◽  
Stefan Prost ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Single Species ◽  
Spotted Hyena ◽  
Genetic Changes ◽  
Slow Decline ◽  
Extant Species ◽  
Phylogenetic Discordance ◽  
Population Sizes ◽  
Olfactory Receptor Genes ◽  
Striped Hyena

AbstractDuring the Miocene, Hyaenidae was a highly diverse family of Carnivora that has since been severely reduced to four extant genera, each of which contains only a single species. These species include the bone-cracking spotted, striped, and brown hyenas, and the specialised insectivorous aardwolf. Previous genome studies have analysed the evolutionary histories of the spotted and brown hyenas, but little is known about the remaining two species. Moreover, the genomic underpinnings of scavenging and insectivory, defining traits of the extant species, remain elusive. To tackle these questions, we generated an aardwolf genome and analysed it together with those from the other three species. We provide new insights into the evolutionary relationships between the species, the genomic underpinnings of their scavenging and insectivorous lifestyles, and their respective genetic diversities and demographic histories. High levels of phylogenetic discordance within the family suggest gene flow between the aardwolf lineage and the ancestral brown/striped hyena lineage. Genes related to immunity and digestion in the bone-cracking hyenas and craniofacial development in the aardwolf showed the strongest signals of selection in their respective lineages, suggesting putative key adaptations to carrion or termite feeding. We also found a family-wide expansion in olfactory receptor genes suggesting that an acute sense of smell was a key early adaptation for the Hyaenidae family. Finally, we report very low levels of genetic diversity within the brown and striped hyenas despite no signs of inbreeding, which we putatively link to their similarly slow decline in Neover the last ∼2 million years. We found much higher levels of genetic diversity in both the spotted hyena and aardwolf and more stable population sizes through time. Taken together, these findings highlight how ecological specialisation can impact the evolutionary history, demographics, and adaptive genetic changes of a lineage.

scholarly journals Lion and spotted hyena distributions within a buffer area of the Serengeti-Mara ecosystem

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stanslaus B. Mwampeta ◽  
Clay M. Wilton ◽  
Imani J. Mkasanga ◽  
Lusato M. Masinde ◽  
Peter S. Ranke ◽  
...  
Keyword(s):  
Anthropogenic Activities ◽  
Spotted Hyena ◽  
The South ◽  
Large Carnivore ◽  
Serengeti Ecosystem ◽  
Northern Tanzania ◽  
Spotted Hyenas ◽  
Western Border ◽  
Eastern Border ◽  
June July

AbstractMost large carnivore populations are declining due to anthropogenic activities including direct persecution, prey depletion, habitat loss and degradation. protected areas (PAs) can help maintain viable large carnivore populations; however, anthropogenic activities occurring near and within PA borders or edges can reduce their effectiveness. We investigated the influence of edge effects on abundance of lions (Panthera leo) and spotted hyenas (Crocuta crocuta) in Maswa Game Reserve (MGR), a part of the Serengeti ecosystem in northern Tanzania. We conducted repeated call-ins to attract and enumerate lions and hyenas at 20 stations in MGR during June–July 2017. We used N-mixture models to estimate hyena and lion abundance in relation to land cover and distance from the south-western MGR borders which are adjacent to villages. We found lowest lion and hyena abundances by the south-western border, with abundance of both species increasing toward the eastern border adjacent to Serengeti National Park. Lions were uniformly distributed among land covers whereas hyenas were more abundant in woodlands. We suggest that reduced lion and hyena abundance near human settlements was in response to depleted prey, due to human actions. We recommend ecologically compatible land uses and effective border patrols to mitigate these adverse effects.

scholarly journals Society, demography and genetic structure in the spotted hyena

2011 ◽  
Vol 21 (3) ◽  
pp. 613-632 ◽  
Author(s):  
KAY E. HOLEKAMP ◽  
JENNIFER E. SMITH ◽  
CHRISTOPHER C. STRELIOFF ◽  
RUSSELL C. VAN HORN ◽  
HEATHER E. WATTS
Keyword(s):  
Genetic Structure ◽  
Spotted Hyena
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