Variation in Condition Indexes Due to Climatic and Seasonal Factors in an Australian Desert Lizard, Amphibolurus-Nuchalis

1991 ◽  
Vol 39 (4) ◽  
pp. 373 ◽  
Author(s):  
SD Bradshaw ◽  
G Death
Keyword(s):  
Body Size ◽  
Analysis Of Covariance ◽  
Physiological Data ◽  
Allometric Relationships ◽  
Explanatory Variables ◽  
Shark Bay ◽  
General Utility ◽  
Seasonal Factors ◽  
Condition Indices ◽  
Free Ranging

The precise nature of the allometric relationships between body size and body mass, water content and solid matter was derived from a sample of over 700 lizards of the agamid species Amphibolurus nuchalis (= Ctenophorus inermis), collected during 1969-82 at Shark Bay in Western Australia. Three condition indices relating each variable to body size, as expressed by snout-vent length, were derived from these allometric relationships for male, female and juvenile lizards. The formation of condition indices was compared to analysis of covariance as a method of analysis of such data. Variation in these indices with weather and season over the period of the study were investigated by means of regression models. Variation between days within trips was relatively small, suggesting a time scale for physiological change of greater than 3-4 days. Ascribing cause to specific weather and seasonal factors was difficult, due to the high colinearity of the explanatory variables. The influence of temperature and rainfall on the condition indices was evident in the model, however, and accords well with physiological data for this species. The extent to which the condition indices could be predicted by a combination of weather and seasonal variables was encouraging, and suggests that the method may have general utility in the study of changes in body composition and condition of free-ranging animals.

scholarly journals WHATEVER YOU WANT: INCONSISTENT RESULTS IS THE RULE, NOT THE EXCEPTION, IN THE STUDY OF PRIMATE BRAIN EVOLUTION

2018 ◽  
Author(s):  
Andreas Wartel ◽  
Patrik Lindenfors ◽  
Johan Lind
Keyword(s):  
Body Size ◽  
Brain Evolution ◽  
Data Sets ◽  
Data Set ◽  
Scientific Rigor ◽  
Explanatory Variables ◽  
Primate Brain ◽  
Residual Variation ◽  
The Many ◽  
Brain Data

AbstractPrimate brains differ in size and architecture. Hypotheses to explain this variation are numerous and many tests have been carried out. However, after body size has been accounted for there is little left to explain. The proposed explanatory variables for the residual variation are many and covary, both with each other and with body size. Further, the data sets used in analyses have been small, especially in light of the many proposed predictors. Here we report the complete list of models that results from exhaustively combining six commonly used predictors of brain and neocortex size. This provides an overview of how the output from standard statistical analyses changes when the inclusion of different predictors is altered. By using both the most commonly tested brain data set and a new, larger data set, we show that the choice of included variables fundamentally changes the conclusions as to what drives primate brain evolution. Our analyses thus reveal why studies have had troubles replicating earlier results and instead have come to such different conclusions. Although our results are somewhat disheartening, they highlight the importance of scientific rigor when trying to answer difficult questions. It is our position that there is currently no empirical justification to highlight any particular hypotheses, of those adaptive hypotheses we have examined here, as the main determinant of primate brain evolution.

scholarly journals Body size development of captive and free-ranging Leopard tortoises (Geochelone pardalis)

Zoo Biology ◽  
2009 ◽  
pp. n/a-n/a ◽  
Author(s):  
Julia Ritz ◽  
Catrin Hammer ◽  
Marcus Clauss
Keyword(s):  
Body Size ◽  
Free Ranging

Brain size/body weight in the dingo (Canis dingo): comparisons with domestic and wild canids

2017 ◽  
Vol 65 (5) ◽  
pp. 292 ◽  
Author(s):  
Bradley P. Smith ◽  
Teghan A. Lucas ◽  
Rachel M. Norris ◽  
Maciej Henneberg
Keyword(s):  
Body Size ◽  
Brain Size ◽  
Cuon Alpinus ◽  
Size Relationship ◽  
Wild Canids ◽  
Free Ranging ◽  
The Impact ◽  
Endocranial Volume ◽  
The Brain

Endocranial volume was measured in a large sample (n = 128) of free-ranging dingoes (Canis dingo) where body size was known. The brain/body size relationship in the dingoes was compared with populations of wild (Family Canidae) and domestic canids (Canis familiaris). Despite a great deal of variation among wild and domestic canids, the brain/body size of dingoes forms a tight cluster within the variation of domestic dogs. Like dogs, free-ranging dingoes have paedomorphic crania; however, dingoes have a larger brain and are more encephalised than most domestic breeds of dog. The dingo’s brain/body size relationship was similar to those of other mesopredators (medium-sized predators that typically prey on smaller animals), including the dhole (Cuon alpinus) and the coyote (Canis latrans). These findings have implications for the antiquity and classification of the dingo, as well as the impact of feralisation on brain size. At the same time, it highlights the difficulty in using brain/body size to distinguish wild and domestic canids.

Comparing three body condition indices in amphibians: a case study of yellow-bellied toad Bombina variegata

2010 ◽  
Vol 31 (4) ◽  
pp. 558-562 ◽  
Author(s):  
Rodica Plăiaşu ◽  
Tibor Hartel ◽  
Raluca Ioana Băncilă ◽  
Dan Cogălniceanu ◽  
Joost Smets
Keyword(s):  
Body Size ◽  
Body Condition ◽  
Condition Index ◽  
Quality Parameters ◽  
Direct Measurements ◽  
Wide Range ◽  
Bombina Variegata ◽  
Condition Indices ◽  
Three Body

AbstractBody condition is important because it is correlated with population and habitat quality parameters. Since the direct measurements are either lethal or unreliable, a wide range of non-lethal body condition indices has been proposed. The aim of our study was to apply and compare three body condition indices (Fulton's index, relative body condition mass index and residual index) using body size indicator – body mass data for 24 populations of the yellow bellied toad (Bombina variegata). The condition index should be independent of body size indicator, in this case snout vent length (SVL). Therefore we tested all three indices for the statistical independence of SVL and for the normality of distribution. Fulton's index violated the independence assumption, whereas the relative body condition mass index did not have a normal distribution. Residual index was found both independent of SVL and normally distributed. Moreover, the residual index highlighted biological significant differences on the basis of altitude and season. Our results recommend the residual index as a useful tool in amphibian monitoring and conservation.

The effects of age, sex, reproductive status and temporal factors on the time-use of free-ranging red kangaroos

1993 ◽  
Vol 20 (6) ◽  
pp. 785 ◽  
Author(s):  
DM Watson ◽  
TJ Dawson
Keyword(s):  
Body Size ◽  
Group Size ◽  
Time Use ◽  
New South ◽  
New South Wales ◽  
Time Of Day ◽  
Adult Males ◽  
South Wales ◽  
Free Ranging ◽  
Foraging Time

The effects of temporal (time of day and season) factors and size, sex, female reproductive state and group size on the diel time-use of free-ranging red kangaroos (Macropus rufus) was examined. Particular emphasis was given to the effects on their foraging behaviour, with foraging divided into cropping, chewing and searching components. The study was conducted in semi-arid western New South Wales from July 1991 to March 1992, a time of deepening drought conditions in New South Wales. Group size had very little influence on the time-use of M. rufus. It was negatively but only weakly correlated with the proportion of foraging time spent chewing (chewing intensity). No significant differences in time-use were found between size classes of adult males (large and medium-sized males), females with or without pouch young, or females with different-sized pouch young (no visible young, small pouch young or large pouch young). Differences occurred between adult males, adult females and subadult kangaroos. These differences were mainly associated with their chewing and searching behaviour and were related to body size; as body size increased the proportion of time spent chewing and the intensity of chewing increased while the proportion of time searching and the proportion of foraging time spent searching (searching intensity) decreased. Neither the proportion of time spent cropping or foraging nor the proportion of foraging time spent cropping (cropping intensity) or the proportion of active time spent foraging (foraging intensity) differed between any size/sex/reproductive class. Temporal effects had a considerable influence on time-use. M. rufus were most active at night and in the few hours after sunrise and sunset. Seasonal changes in time-use were largely a result of changes in daytime behaviour. M. rufus foraged less and rested more during the day in winter than in spring or summer. There was no increase in the intensity or proportion of time spent foraging or cropping at night to compensate for the reduction in diurnal foraging. It is hypothesised that temporal variations in time-use were related to variations in weather and vegetation conditions.

Comparison of vocalisations of introduced European red deer stags (Cervus elaphus) in north-western Patagonia (Argentina) with native European populations

2012 ◽  
Vol 52 (8) ◽  
pp. 714 ◽  
Author(s):  
A. M. Hurtado ◽  
J. M. Smith-Flueck ◽  
P. Black-Decima
Keyword(s):  
Body Size ◽  
Cervus Elaphus ◽  
Red Deer ◽  
Vocal Tract ◽  
Acoustical Properties ◽  
Andean Cordillera ◽  
Northern European ◽  
Acoustic Study ◽  
Free Ranging ◽  
European Populations

Polygynous deer are very vocal species, producing calls in various contexts. Male rutting calls in red deer (Cervus elaphus) have been most studied in captive and/or free-ranging European populations. The recent application of ‘source-filter theory’ has identified the independent roles of fundamental frequency (F0) and formants in the production of deer calls and demonstrated the relation between formant spacing and anatomical characteristics such as body size. The present paper describes and characterises the acoustical properties of male rutting vocalisations for a free-ranging red deer population located in the ecotone of the eastern Andean cordillera within the Nahuel Huapi National Reserve (Neuquén, Argentina), and is the first acoustic study of free-ranging red deer stags outside their historic distribution. Recordings were made of seven identified and several unidentified stags at the peak of the rut in 2007. Calculated F0 was found to be higher for these identified stags than for Scottish red deer on the island of Rhum. The analysis of formant spacing was used to calculate the length of the vocal tract (VTL) for the seven males studied; values were comparable to those found in stags from Rhum. The longest calculated VTLs within these males corresponded to those of the four stags with the largest antler racks and the only stags holding harems. Previous studies have shown that VTL correlates with body size, age and reproductive success and that these deer have the ability to lower their larynx and extend their vocal tracts to a maximum, which is probably under sexual selection. Our data fit with this explanation. The higher F0s recorded in this population may result from the influence of wapiti genes, known to be present in these deer, because wapiti have a much higher-frequency rutting call, namely, the bugle. Alternatively, they may be related to the mating strategy, which differs substantially from the northern European populations.

scholarly journals Brain Changes during Phyletic Dwarfing in Elephants and Hippos

2018 ◽  
Vol 92 (3-4) ◽  
pp. 167-181 ◽  
Author(s):  
George A. Lyras
Keyword(s):  
Body Size ◽  
Brain Size ◽  
Size Increase ◽  
Allometric Relationships ◽  
Scaling Models ◽  
Brain Changes ◽  
Relative Brain Size

Of all known insular mammals, hippos and elephants present the extremes of body size decrease, reducing to 4 and a mere 2% of their ancestral mainland size, respectively. Despite the numerous studies on these taxa, what happens to their relative brain size during phyletic dwarfing is not well known, and results are sometimes conflicting. For example, relative brain size increase has been noted in the Sicilian dwarf elephant, Palaeoloxodon falconeri, whereas relative brain size decrease has been postulated for Malagasy dwarf hippos. Here, I perform an analysis of brain, skull, and body size of 3 insular elephants (Palaeoloxodon “mnaidriensis,” P. tiliensis, and P. falconeri) and 3 insular hippos (Hippopotamus madagascariensis, H. lemerlei, and H. minor) to address this issue and to test whether relative brain size in phyletic dwarf species can be predicted. The results presented here show that the encephalization of all insular elephants and hippos is higher than that of their continental relatives. P. falconeri in particular has an enormous encephalization increase, which has so far not been reported in any other insular mammal. Insular brain size cannot be reliably predicted using either static allometric or ontogenetic scaling models. The results of this study indicate that insular dwarf species follow brain-body allometric relationships different from the expected patterns seen for their mainland relatives.

scholarly journals Modeling Longitudinal Changes in Maximal-Intensity Exercise Performance in Young Male Rowing Athletes

2012 ◽  
Vol 24 (2) ◽  
pp. 187-198 ◽  
Author(s):  
Pavle Mikulic ◽  
Tomislav Blazina ◽  
Alan M. Nevill ◽  
Goran Markovic
Keyword(s):  
Body Size ◽  
Exercise Performance ◽  
Power Output ◽  
Young Male ◽  
Maximal Power ◽  
Mean Power ◽  
Maximal Power Output ◽  
Explanatory Variables ◽  
Maximal Intensity ◽  
Performance Development

The purpose of the current study was to examine the effect of age and body size upon maximal-intensity exercise performance in young rowing athletes. Male participants n = 171) aged 12–18 years were assessed using an “all-out” 30-s rowing ergometer test, and reassessed after 12 months. The highest rate of performance development, which amounts to [mean(SD)] +34%(23%) and +32%(23%) for mean and maximal power output, respectively, is observed between the ages of 12 and 13, while this rate of development gradually declines as the athletes mature through adolescence. Performance increases with body size, and mass, stature and chronological age all proved to be significant (all p < .05) explanatory variables of mean power output, with respective exponents [mean(SE)] of 0.56(0.08), 1.84(0.30) and 0.07(0.01), and of maximal power output, with respective exponents of 0.54(0.09), 1.76(0.32) and 0.06(0.01). These findings may help coaches better understand the progression of rowing performance during adolescence.

Escargots through time: an energetic comparison of marine gastropod assemblages before and after the Mesozoic Marine Revolution

Paleobiology ◽  
2011 ◽  
Vol 37 (2) ◽  
pp. 252-269 ◽  
Author(s):  
Seth Finnegan ◽  
Craig M. McClain ◽  
Matthew A. Kosnik ◽  
Jonathan L. Payne
Keyword(s):  
Body Size ◽  
Metabolic Rate ◽  
Net Primary Production ◽  
Average Energy ◽  
Late Triassic ◽  
Physiological Data ◽  
Marine Animal ◽  
Before And After ◽  
Per Capita ◽  
Mesozoic Marine Revolution

The modern structure of marine benthic ecosystems was largely established during the Jurassic and Early Cretaceous (200–100 Ma), a transition that has been termed the Mesozoic Marine Revolution (MMR). Although it has been suggested that the MMR marks an increase in the average energy consumption of marine animal ecosystems, this hypothesis has not been evaluated quantitatively. In this study, we integrate body size and abundance data from the fossil record with physiological data from living representatives to estimate mean per capita metabolic rates of tropical to subtropical assemblages of shallow-marine gastropods—a major component of marine ecosystems throughout the Meso-Cenozoic—both before and after the MMR. We find that mean per capita metabolic rate rose by ∼150% between the Late Triassic and Late Cretaceous and remained relatively stable thereafter. The most important factor governing the increase in metabolic rate was an increase in mean body size. In principle, this size increase could result from secular changes in sampling and taphonomic biases, but these biases are suggested to yield decreases rather than increases in mean size. Considering that post-MMR gastropod diversity is dominated by predators, the net primary production required to supply the energetic needs of the average individual increased by substantially more than 150%. These data support the hypothesis that benthic energy budgets increased during the MMR, possibly in response to rising primary productivity.

scholarly journals Deriving condition indices from standard fisheries databases and evaluating their sensitivity to variation in stored energy reserves

2004 ◽  
Vol 61 (10) ◽  
pp. 1900-1917 ◽  
Author(s):  
C Tara Marshall ◽  
Coby L Needle ◽  
Nathalia A Yaragina ◽  
Adnan M Ajiad ◽  
Evgeny Gusev
Keyword(s):  
Body Size ◽  
Gadus Morhua ◽  
Barents Sea ◽  
Condition Index ◽  
Energy Reserves ◽  
Stored Energy ◽  
Stock Level ◽  
Length Relationship ◽  
Condition Indices

To evaluate interstock differences in condition, it would be advantageous to develop stock-level condition indices from standardized databases on weight and length. This study describes a method for estimating stock-level condition when individual-level observations on length and weight are not easily accessible. For each year in a 56-year time series (1946–2001) for Northeast Arctic cod (Gadus morhua), pseudo-observations of weight and length were generated by pairing the Norwegian and Russian values for weight-at-age provided annually to the assessment working group with estimates of length-at-age derived from the same databases. A weight–length relationship fit to each year was then used to predict weight-at-length, i.e., girth, for a range of standard lengths (30–120 cm). This index was uncorrelated with both the liver condition index and the abundance of Barents Sea capelin (Mallotus villosus), suggesting that at the stock level, the girth of cod is not necessarily indicative of the magnitude of stored energy reserves. Partitioning body size into length-at-age and girth revealed long-term trends in body size. In particular, large/old cod showed substantially higher values of both length-at-age and girth that could be the result of long-term increases in fishing mortality.

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