Brain and Body Size Relations among Spotted Hyenas (Crocuta crocuta)

2018 ◽  
Vol 92 (1-2) ◽  
pp. 82-95
Author(s):  
Michael D. Mann ◽  
Lawrence G. Frank ◽  
Stephen E. Glickman ◽  
Arnold L. Towe
Keyword(s):  
Body Size ◽  
Brain Size ◽  
Negative Relationship ◽  
Crocuta Crocuta ◽  
Spotted Hyena ◽  
Spotted Hyenas ◽  
Body Weights ◽  
Vertebrate Zoology ◽  
Males And Females ◽  
The Relationship

The relationship between brain size and body size across species “from mouse to elephant” is described by a function of positive slope. Almost uniformly, the relationship between brain size and body size within a species has a positive slope, though this is less steep than across species. The spotted hyena, Crocuta crocuta, differs from most other mammals in a number of ways including the fact that, on average, adult females weigh more than adult males and occasionally display greater body lengths. Brains of 5 female and 4 male hyenas were weighed in the field near Moyale in Northern Kenya, and body weights and body lengths were obtained from the same animals. When our analyses of brain/body relationships in these animals revealed an unanticipated negative relationship between brain size and body length, we extended our measurements to include intracranial volume in 19 skulls (8 females and 11 males) from the collection at the Museum of Vertebrate Zoology, University of California Berkeley; body weights and lengths were also available. A third dataset was formed by measuring intracranial volumes in 60 spotted hyena skulls (27 females and 33 males) in the Natural History Museum, London, UK; body lengths and intracranial volumes were available. Brain/body size slopes, in general, were not significantly different from zero except in 3 cases: brain weight/body length for Moyale males alone and males and females together, and cranial volume/body weight for Museum of Vertebrate Zoology males and females together. Although most of the slopes were not significantly different from zero, they were all negative, and a statistical test which combined probabilities from the 3 datasets supports the conclusion that there is a negative relationship between brain size and body size in spotted hyenas. Possible explanations for the negative slopes are discussed, including costs and benefits of large brains and large bodies and physiological mechanisms.

Glacial/Interglacial Size Variation in Fossil Spotted Hyenas (Crocuta crocuta) from Britain

1989 ◽  
Vol 32 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Richard G. Klein ◽  
Katharine Scott
Keyword(s):  
Body Size ◽  
Temperature Variation ◽  
Late Pleistocene ◽  
Size Variation ◽  
Crocuta Crocuta ◽  
Bergmann’S Rule ◽  
Spotted Hyena ◽  
Bergmann's Rule ◽  
Spotted Hyenas ◽  
The Relationship

AbstractThe lower carnassial lengths of spotted hyenas (Crocuta crocuta) in 12 late Pleistocene samples from Britain indicate that, on average, local hyenas of the last (Devensian) glaciation were significantly larger than their last-interglaciation (Ipswichian) counterparts. Together with the tendency for spotted hyena carnassial length to increase with latitude in present-day Africa, this suggests that spotted hyena body size is inversely related to temperature, as predicted by Bergmann's rule. The implication is that spotted hyena carnassial length can be used as an independent gauge of Pleistocene temperature variation, though the combined African and British data imply that the relationship between carnassial length and temperature is curvilinear, such that as temperature declines, equal amounts of further decline produce progressively smaller increases in average carnassial length.

EEG-correlates of work efficiency level among young persons with stress-induced bruxism

2021 ◽  
pp. 25-29
Author(s):  
A. E. Barulin ◽  
S. V. Klauchek ◽  
A. E. Klauchek
Keyword(s):  
Regression Models ◽  
Alpha Rhythm ◽  
Negative Relationship ◽  
Maximum Amplitude ◽  
Dominant Frequency ◽  
Regression Equations ◽  
Microsoft Excel ◽  
The Subject ◽  
Males And Females ◽  
The Relationship

Purpose of the study. To establish the relationship between neurophysiological status and the level of efficiency in young people with bruxism.Materials and methods. Two groups of 64 and 53 subjects (males and females) aged 20–35 years old with bruxism and non-bruxers were formed according to questionnaire results and physical examination. The level of efficiency was assessed by the results of sensorimotor tracking of a moving object (the ‘Smile’ model). Spectral analysis was performed for evaluation of the baseline electroencephalograms. Microsoft Excel and Statistica 10.0 programs were used for statistical data processing.Results. The level of efficiency was statistically significantly lower in the hardest test of Smile model among the individuals with bruxism (p < 0.05). The bruxers also demonstrated a significantly lower dominant frequency and maximum amplitude of alpha-rhythm (p < 0.05), and significantly higher dominant frequency of beta2 rhythm (p < 0.05). The dominant frequency and the maximum amplitude of the alpha-rhythm are parameters corresponding to significant coefficients of the regression analysis. A negative relationship was found between the degree of error during sensorimotor tracking and the frequency and amplitude of alpha-rhythm.Conclusion. Regression models present the relationship between the level of efficiency and the alpha-rhythm severity. The regression equations make it possible to determine the functional state of the subject using an electroencephalogram.

Taphonomic and zooarchaeological implications of spotted hyena (Crocuta crocuta) bone accumulations in Kenya: a modern behavioral ecological approach

Paleobiology ◽  
2009 ◽  
Vol 35 (2) ◽  
pp. 289-309 ◽  
Author(s):  
Sarah W. Lansing ◽  
Susan M. Cooper ◽  
Erin E. Boydston ◽  
Kay E. Holekamp
Keyword(s):  
Behavioral Ecology ◽  
Prey Species ◽  
Species Abundance ◽  
Crocuta Crocuta ◽  
Site Formation ◽  
Behavioral Variability ◽  
Spotted Hyena ◽  
Site Formation Processes ◽  
Spotted Hyenas ◽  
Bone Accumulation

The significant impact of extant carnivores, particularly spotted hyenas, on the depositional history and physical characteristics of archaeofaunal and paleontological assemblages is well recognized. We focus on the behavioral ecology of extant spotted hyenas (Crocuta crocuta) in relation to bone accumulations produced by one East African clan at communal dens. Limbs and skulls of prey animals more frequently appear at dens than do other carcass portions. These items reflect the relative abundance of prey species near dens; carnivore remains are poorly represented. Comparative analysis reveals that bones are deposited far more slowly (<7 carcass portions per month) and accumulations tend to be smaller at Crocuta dens than at dens of either brown (Parahyaena brunnea) or striped (Hyaena hyaena) hyenas. We propose that extant Crocuta bone accumulation rates and sizes are likely affected by prey species abundance, clan size, social interactions within the clan, and the type and availability of den sites. We also suggest that the potential for intraspecific behavioral variability in bone accumulation patterns is important when comparisons are made among spotted hyena populations and across hyena species. For example, accumulation patterns may be dramatically influenced by the temporal span, potentially ranging from days to hundreds or thousands of years, in which bones are collected, depending on the species-specific history of occupation at a given site. Understanding the behavioral and ecological variability likely to influence bone accumulation patterns at dens used by different hyaenids will allow taphonomists and zooarchaeologists to refine their knowledge of mechanisms underlying site formation processes and potential causes of variability in deeper-time den assemblages.

scholarly journals Post-weaning maternal effects and the evolution of female dominance in the spotted hyena

2009 ◽  
Vol 276 (1665) ◽  
pp. 2291-2298 ◽  
Author(s):  
Heather E. Watts ◽  
Jaime B. Tanner ◽  
Barbara L. Lundrigan ◽  
Kay E. Holekamp
Keyword(s):  
Crocuta Crocuta ◽  
Female Dominance ◽  
Spotted Hyena ◽  
Compensatory Mechanism ◽  
Feeding Apparatus ◽  
Skull Development ◽  
Spotted Hyenas ◽  
Selection For ◽  
Maternal Presence ◽  
New Hypothesis

Mammalian societies in which females dominate males are rare, and the factors favouring the evolution of female dominance have yet to be clearly identified. We propose a new hypothesis for the evolution of female dominance and test its predictions with empirical data from the spotted hyena ( Crocuta crocuta ), a well-studied species characterized by female dominance. We suggest that constraints imposed by the development of a feeding apparatus specialized for bone cracking, in combination with the intensive feeding competition characteristic of spotted hyenas, led to the evolution of female dominance. Specifically, we propose that protracted development of the feeding apparatus in young hyenas led to selection for increased aggressiveness in females as a compensatory mechanism for mothers to secure food access for their young after weaning. Our analyses yielded results consistent with this hypothesis. Morphological and behavioural measurements indicate that skull development is indeed protracted in this species; spotted hyenas do not achieve adult skull size or feeding performance capabilities until after sexual maturity. The period between weaning and completed skull development is particularly challenging, as indicated by high mortality. Finally, maternal presence between weaning and full skull maturity, as well as the relative ability of females to aggressively displace conspecifics from food, are important determinants of offspring survival.

scholarly journals Some Remarks on Bird's Brain and Behavior under the Constraints of Domestication

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Julia Mehlhorn ◽  
Gerd Rehkämper
Keyword(s):  
New Species ◽  
Body Size ◽  
Brain Size ◽  
Evolutionary Process ◽  
Brain Morphology ◽  
Domestic Poultry ◽  
Brain And Behavior ◽  
And Behavior ◽  
The Relationship

The relationship between domestication and evolution is still a matter of discussion. In this review, we present some arguments for the assumption that domestication could be seen as an evolutionary process including the possibility that new species might evolve. In course of domestication, many breeds have been developed which show numerous alterations in different parameters such as body size, coloring, habitat, behavior, and brain size and composition. Here, we would like to give an overview particularly about alterations and varieties in (brain) morphology and behavior in domestic poultry and argue that these alterations could be seen as adaptations to the man-made environment.

scholarly journals Exceptional body sizes but typical trophic structure in a Pleistocene food web

2016 ◽  
Vol 12 (5) ◽  
pp. 20160228 ◽  
Author(s):  
Angel M. Segura ◽  
Richard A. Fariña ◽  
Matías Arim
Keyword(s):  
Body Size ◽  
Trophic Position ◽  
Negative Relationship ◽  
Additional Energy ◽  
Quaternary Period ◽  
Species Vulnerability ◽  
Body Sizes ◽  
Energetic Constraints ◽  
The Relationship

In this study, we focused on the exceptionally large mammals inhabiting the Americas during the Quaternary period and the paramount role of body size in species ecology. We evaluated two main features of Pleistocene food webs: the relationship between body size and (i) trophic position and (ii) vulnerability to predation. Despite the large range of species sizes, we found a hump-shaped relationship between trophic position and body size. We also found a negative trend in species vulnerability similar to that observed in modern faunas. The largest species lived near the boundary of energetic constraints, such that any shift in resource availability could drive these species to extinction. Our results reinforce several features of megafauna ecology: (i) the negative relationship between trophic position and body size implies that large-sized species were particularly vulnerable to changes in energetic support; (ii) living close to energetic imbalance could favour the incorporation of additional energy sources, for example, a transition from a herbivorous to a scavenging diet in the largest species (e.g. Megatherium ) and (iii) the interactions and structure of Quaternary megafauna communities were shaped by similar forces to those shaping modern fauna communities.

Size Matters: Body Size is Correlated with Longevity in Speckled Cockroaches (Nauphoeta cineria).

2021 ◽  
Vol 14 ◽  
Author(s):  
Sami Badwan ◽  
James Harper
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Body Length ◽  
Individual Species ◽  
Time Of Death ◽  
Large Size ◽  
The Status ◽  
Males And Females ◽  
The Relationship ◽  
Individual Body

Background: A relationship between body size and longevity has long been appreciated within eukaryotes, especially vertebrates. Introduction: In general, large size is associated with increased longevity among species of mammals and birds but is associated with decreased longevity within individual species such as dogs and mice. In this study, we examined the relationship between measures of individual body size and longevity in a captive population of speckled cockroaches (Nauphoeta cineria). Method: Newly molted adults of both sexes were removed from a mass colony housed in multiple terraria and housed individually with food and water provided ad libitum for the duration of their lifespan. Thrice weekly, the status (i.e. live/dead) of individual cockroaches was noted for the duration of the study. Individuals found dead were weighed and measured to obtain body mass and morphometric measures and the age at the time of death was recorded. The relationship between body size and lifespan was assessed. Result: Contrary to what is commonly seen within vertebrates, large cockroaches were longer-lived than their smaller counterparts. Specifically, body mass, body length and pronotum width were all significantly correlated with the age at death in a mixed population of males and females (n = 94). In addition, we found that the longevity of a historically larger population in terms of both body mass and body length were significantly longer-lived than the population used in this study. Conclusion: These data indicate there is a significant interaction between body size and aging in this species and that increased size results in a survival advantage. There is evidence in the literature indicating that a positive relationship between size and longevity may be common in insects.

A keystone predator at risk? Density and distribution of the spotted hyena (Crocuta crocuta) in the Etosha National Park, Namibia

2009 ◽  
Vol 87 (10) ◽  
pp. 941-947 ◽  
Author(s):  
Martina Trinkel
Keyword(s):  
National Park ◽  
Spatial Relationship ◽  
Crocuta Crocuta ◽  
Spotted Hyena ◽  
Migratory Species ◽  
Mathematical Correlation ◽  
Equus Burchelli ◽  
Spotted Hyenas ◽  
The Status ◽  
Connochaetes Taurinus

For wildlife management and conservation biology, it is important to be able to estimate the status and distribution of animals and to monitor their population trends. In the Etosha National Park, Namibia, there is a lack of knowledge about numbers and distribution of spotted hyenas ( Crocuta crocuta (Erxleben, 1777)) and factors regulating their population. To estimate hyena density and distribution, tape-recorded vocalizations (call-ups) were performed to attract hyenas in the central and eastern parts of Etosha. Eighty-five adult and subadult hyenas responded to the calls, with most of them responding in an area with high density of migratory ungulates, principally springbok ( Antidorcas marsupialis (Zimmermann, 1780)), wildebeest ( Connochaetes taurinus (Burchell, 1823)), and Burchell’s zebra ( Equus burchelli (Gray, 1824)). These migratory species are the main prey of spotted hyenas in Etosha. There was a strong spatial relationship between hyena density and migratory prey biomass. Based on this mathematical correlation, I estimated 203 ± 79 hyenas, i.e., 2.7 ± 1.1 hyenas/100 km2, in the central and eastern parts of Etosha. Applying this correlation to the western part of the park, it was possible to estimate 339 ± 176 spotted hyenas, corresponding to an overall density of 2.1 ± 1.0 hyenas/100 km2, in the whole Etosha National Park.

Androgenic influences on body size and composition of adult rhesus monkeys

1988 ◽  
Vol 255 (6) ◽  
pp. E857-E864 ◽  
Author(s):  
J. W. Kemnitz ◽  
K. K. Sladky ◽  
T. J. Flitsch ◽  
S. M. Pomerantz ◽  
R. W. Goy
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Rhesus Monkeys ◽  
Testosterone Propionate ◽  
Base Line ◽  
Lean Tissue ◽  
Anabolic Hormones ◽  
Crown Rump Length ◽  
Body Weights ◽  
Males And Females

The effects of daily treatment with testosterone propionate (TP, 2 mg/kg) and dihydrotestosterone propionate (DHTP, 2 mg/kg) were examined in rhesus monkeys in three experiments. In experiments 1 and 2, males and females gonadectomized in infancy, and female pseudohermaphrodites produced by prenatal exposure to TP or DHTP and gonadectomized postpubertally, were studied in conjunction with intact males (IM). The IM group was heavier in adulthood than the three gonadectomized groups, which did not differ in body weight from each other. Genetic males had greater crown-rump length than genetic females. Treatment of the gonadectomized groups with TP produced large increases in body mass (averaging approximately 50%) that were attributable to accretion of lean tissue. This effect did not differ significantly between males and females. In experiment 3, additional groups of males that had been castrated as infants were given daily injections with DHTP or oil. The DHTP treatment resulted in increases in body size that were not different from those seen following TP treatment. When TP and DHPT treatments were discontinued, body weights and dimensions reverted to base-line values. Increased body size induced by TP and DHTP was accomplished without reliable increases in food intake. Because testosterone (T) is metabolized to dihydrotestosterone (DHT), while DHT cannot be converted to T, these results show that both T and DHT are effective anabolic hormones in rhesus.

scholarly journals A Review of Effects of Environment on Brain Size in Insects

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 461
Author(s):  
Thomas Carle
Keyword(s):  
Body Size ◽  
Social Behaviour ◽  
Brain Size ◽  
Social Brain ◽  
Encephalization Quotient ◽  
The Social ◽  
Relative Brain Size ◽  
The Relationship ◽  
Development And Evolution

Brain size fascinates society as well as researchers since it is a measure often associated with intelligence and was used to define species with high “intellectual capabilities”. In general, brain size is correlated with body size. However, there are disparities in terms of relative brain size between species that may be explained by several factors such as the complexity of social behaviour, the ‘social brain hypothesis’, or learning and memory capabilities. These disparities are used to classify species according to an ‘encephalization quotient’. However, environment also has an important role on the development and evolution of brain size. In this review, I summarise the recent studies looking at the effects of environment on brain size in insects, and introduce the idea that the role of environment might be mediated through the relationship between olfaction and vision. I also discussed this idea with studies that contradict this way of thinking.

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