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.

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.

Apparent source level of free-ranging humpback dolphin, Sousa chinensis, in the South China Sea

2014 ◽  
Vol 96 (4) ◽  
pp. 845-851 ◽  
Author(s):  
Satoko Kimura ◽  
Tomonari Akamatsu ◽  
Liang Fang ◽  
Zhitao Wang ◽  
Kexiong Wang ◽  
...  
Keyword(s):  
Body Size ◽  
Bimodal Distribution ◽  
Anthropogenic Activity ◽  
Train Duration ◽  
Apparent Source ◽  
Click Train ◽  
Similar Body ◽  
Passive Acoustic ◽  
Hydrophone Array ◽  
Free Ranging

The acoustic performance and behaviour of free-ranging cetaceans requires investigation under natural conditions to understand how wild animals use sound. This is also useful to develop quantitative evaluation techniques for passive acoustic monitoring. There have been limited studies on the acoustics of the Indo-Pacific humpback dolphin; nevertheless, this species is of particular concern because of the anthropogenic activity in the coastal habitats. In the present study, we used a four-hydrophone array to estimate the apparent source levels (ASLs) of biosonar sequences (click trains), of this species in San-Niang Bay, China. As the dolphins approached the array, 173 click trains were found to meet the criteria of on-axis sounds produced within 60 m of the equipment. In total, 121 unclipped click trains were used for the ASL estimation. The qualified click trains contained 36.3 ± 32.5 clicks, lasting for 1.5 ± 1.5 s, with average inter-click intervals (ICIs) of 51.2 ± 38.3 ms. Average ICIs showed a bimodal distribution, with a cut-off at 20 ms. Short-range click trains, with short ICIs of <20 ms on average, were characterized by smaller ASLs, relatively stable ICIs and a shorter click train duration. The mean back-calculated ASL for humpback dolphins with an approximately maximum body size of 2.5 m was 181.7 ± 7.0 dB re 1 μPa at a distance of 1.6–57.2 m. This value was comparable to that recorded for other dolphins of similar body size, although the ASL estimates obtained in this study might be conservative.

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 Stroke frequency, but not swimming speed, is related to body size in free-ranging seabirds, pinnipeds and cetaceans

2006 ◽  
Vol 274 (1609) ◽  
pp. 471-477 ◽  
Author(s):  
Katsufumi Sato ◽  
Yutaka Watanuki ◽  
Akinori Takahashi ◽  
Patrick J.O Miller ◽  
Hideji Tanaka ◽  
...  
Keyword(s):  
Body Size ◽  
Marine Mammals ◽  
Breath Hold ◽  
Sperm Whales ◽  
Stroke Frequency ◽  
Scaling Relationship ◽  
Theoretical Predictions ◽  
Large Animals ◽  
Free Ranging ◽  
Stroke Cycle

It is obvious, at least qualitatively, that small animals move their locomotory apparatus faster than large animals: small insects move their wings invisibly fast, while large birds flap their wings slowly. However, quantitative observations have been difficult to obtain from free-ranging swimming animals. We surveyed the swimming behaviour of animals ranging from 0.5 kg seabirds to 30 000 kg sperm whales using animal-borne accelerometers. Dominant stroke cycle frequencies of swimming specialist seabirds and marine mammals were proportional to mass −0.29 ( R 2 =0.99, n =17 groups), while propulsive swimming speeds of 1–2 m s −1 were independent of body size. This scaling relationship, obtained from breath-hold divers expected to swim optimally to conserve oxygen, does not agree with recent theoretical predictions for optimal swimming. Seabirds that use their wings for both swimming and flying stroked at a lower frequency than other swimming specialists of the same size, suggesting a morphological trade-off with wing size and stroke frequency representing a compromise. In contrast, foot-propelled diving birds such as shags had similar stroke frequencies as other swimming specialists. These results suggest that muscle characteristics may constrain swimming during cruising travel, with convergence among diving specialists in the proportions and contraction rates of propulsive muscles.

Niche partitioning within a population of sea snakes is constrained by ambient thermal homogeneity and small prey size

2020 ◽  
Vol 129 (3) ◽  
pp. 644-651 ◽  
Author(s):  
Claire Goiran ◽  
Gregory P Brown ◽  
Richard Shine
Keyword(s):  
Body Size ◽  
Habitat Use ◽  
New Caledonia ◽  
Niche Partitioning ◽  
Thermal Conditions ◽  
The Body ◽  
Small Prey ◽  
Sea Snakes ◽  
Local Extirpation ◽  
Free Ranging

Abstract In many populations of terrestrial snakes, the phenotype of an individual (e.g. body size, sex, colour) affects its habitat use. One cause for that link is gape limitation, which can result in larger snakes eating prey that are found in different habitats. A second factor involves thermoregulatory opportunities, whereby individuals select habitats based upon thermal conditions. These ideas predict minimal intraspecific variation in habitat use in a species that eats small prey and lives in a thermally uniform habitat, such as the sea snake Emydocephalus annulatus, which feeds on tiny fish eggs and lives in inshore coral reefs. To test that prediction, we gathered data on water depths and substrate attributes for 1475 sightings of 128 free-ranging E. annulatus in a bay near Noumea, New Caledonia. Habitat selection varied among individuals, but with a preference for coral-dominated substrates. The body size and reproductive state of a snake affected its detectability in deep water, but overall habitat use was not linked to snake body size, colour morph, sex or pregnancy. A lack of ontogenetic shifts in habitat use allows extreme philopatry in E. annulatus, thereby reducing gene flow among populations and, potentially, delaying recolonization after local extirpation events.

Thermal performance responses in free-ranging elasmobranchs depend on habitat use and body size

Oecologia ◽  
2019 ◽  
Vol 191 (4) ◽  
pp. 829-842 ◽  
Author(s):  
Karissa O. Lear ◽  
Nicholas M. Whitney ◽  
David L. Morgan ◽  
Lauran R. Brewster ◽  
Jeff M. Whitty ◽  
...  
Keyword(s):  
Body Size ◽  
Habitat Use ◽  
Thermal Performance ◽  
Free Ranging
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