Seasonal patterns of activity and body mass in the plains vizcacha, Lagostomus maximus (family Chinchillidae)

1993 ◽  
Vol 71 (5) ◽  
pp. 1041-1045 ◽  
Author(s):  
Lyn C. Branch

Activity patterns of adult male, adult female, and immature plains vizcacha (Lagostomus maximus) were compared throughout the year, and seasonal changes in body mass were documented for adults. All sex–age classes spent more time feeding in winter and less time at the den site (vizcachera) than in other seasons. The pattern was reversed for summer. Seasonal changes in activity budgets for males were associated with an increase in male–male conflicts and territorial displays at the vizcachera. Body mass of males declined in summer, when they were competing for access to areas used by females, and reached a minimum during the fall breeding season. Females spent less time foraging and more time at the den site after parturition in spring. Body mass of females did not change significantly with season. Throughout the year, activity patterns were similar for females and immatures. During all seasons, adult males spent less time foraging and more time at the vizcachera than other sex–age classes did. From a variety of observations, I suggest that the costs of reproduction, including mass loss, shorter feeding time, and short tenure in a social group, are high for male vizcachas.

1995 ◽  
Vol 18 (1) ◽  
pp. 71
Author(s):  
J.L. Gardner ◽  
M. Serena

The Water Rat Hydromys chrysogaster is Australia's largest amphibious rodent, occupying freshwater rivers, lakes, and coastal and estuarine habitats throughout the continent (Watts and Aslin 1981). Little is known of the species' social organisation or use of space in the wild although Harris (1978) suggested that adults might be intrasexually aggressive. The home ranges of all sex and age classes overlap to some extent but home ranges of adults of the same sex appear to overlap less (Harris 1978). Adult males occupy the largest home ranges which overlap those of one or more females. In captivity individuals kept in groups form hierarchies in which only the dominant females usually breed successfully (Olsen 1982). Fighting occurs primarily among males, with the highest incidence of injuries observed at the beginning of the main September-March breeding season (Olsen 1980, 1982). The results of trapping studies indicate that population density may vary considerably, with the greatest numbers of animals typically occupying man-modified habitats such as irrigation channels or fish farms (McNally 1960, Watts and Aslin 1981, Smales 1984). Aggressive behaviour appears to be related to pelage colour (phenotype) and population density; the higher the density the greater the number of injured individuals (Olsen 1980).


1990 ◽  
Vol 68 (3) ◽  
pp. 470-475 ◽  
Author(s):  
Morten Ryg ◽  
Thomas G. Smith ◽  
Nils Are Øritsland

Seasonal changes in body mass and body composition of ringed seals (Phoca hispida) from the Svalbard Islands are described. The blubber content of adult females decreased from a high of about 50% at the beginning of the pupping season in March–April to a low of 31% during moulting in June. In adult males, the blubber content decreased from 41% in March to 29% in June. By estimating an individual seal's body mass by 1 April from its standard body length, we calculated an average daily loss of body mass of 160 g/day in adult females and 100 g/day in adult males from the start of lactation to the middle of moulting. The blubber content of sexually immature seals was less in June and July than in April, but the seasonal changes were smaller than in adult seals. We found no evidence of significant changes in core mass in adult seals, and suggest that the seasonal body mass changes are mostly due to changes in body fat content.


2010 ◽  
Vol 88 (2) ◽  
pp. 224-230 ◽  
Author(s):  
Daniel Esler ◽  
Jeanine C. Bond

Considerations of acquisition of energy for reproduction by waterfowl have disproportionately focused on females, although males also require energy for reproduction. We quantified variation in body mass of male Harlequin Ducks ( Histrionicus histrionicus (L., 1758)) on coastal wintering areas prior to spring migration, as well as on breeding grounds, to determine when and where nutrients were acquired to meet costs of reproduction. Male mass on wintering grounds increased, on average, by 45 g (7%) in the weeks prior to migration. On breeding streams, we inferred that body mass of paired males decreased with the length of time on breeding grounds. Also, on average, male mass was considerably lower on breeding streams than when they departed coastal wintering sites. We conclude that males store nutrients on marine wintering grounds for subsequent use during the breeding season. Male Harlequin Ducks are highly vigilant while on breeding streams and the associated reduction in feeding time presumably requires energy stores. We suggest that males have evolved a strategy that is at least partially “capital” for meeting costs of reproduction, in which they acquire an optimal amount of energy reserves prior to spring migration and subsequently invest them in behaviours that can enhance reproductive success.


1994 ◽  
Vol 72 (9) ◽  
pp. 1625-1632 ◽  
Author(s):  
Deane Renouf ◽  
Rosemary Gales

The metabolic rate of nine harp seals was measured chronically over a 12-month period using indirect calorimetry. The extent to which the seals' oxygen consumption was predicted by the allometric equation relating basal metabolic rate to body mass depended upon how the former was operationally defined and on the breeding status, sex, and age of the animal. There were large seasonal changes in the oxygen consumption of adult males and reproductive females when metabolic rate was defined as the lowest hourly mean [Formula: see text] in, typically, 23 h of measurement. From April until August, the males' metabolic rate averaged as much as 83% higher than the allometric prediction from body mass, but for the rest of the year their oxygen consumption was not different from the expected value for mammals. Pregnant and pseudopregnant females showed a brief spring elevation in metabolic rate, but otherwise their oxygen consumption was well below that predicted by allometry. In one female who spontaneously aborted some 7 months after insemination, [Formula: see text] increased to the value for mammals shortly thereafter, to a level resembling that of the only female who was not pregnant and who showed no seasonal variation in oxygen consumption. The immature seals' records are highly variable, showing no clear intra-annual pattern; however, their metabolic rates were lower than expected for young mammals. All seasonal shifts were in the opposite direction to the large changes in body mass exhibited by these seals. The effect of these findings in reducing the calculated impact of harp seals on the North West Atlantic fishery is discussed.


2003 ◽  
Vol 81 (5) ◽  
pp. 803-815 ◽  
Author(s):  
Jianbin Shi ◽  
R I.M Dunbar ◽  
David Buckland ◽  
David Miller

The activity budgets of feral goats (Capra hircus) on the Isle of Rum, northwest Scotland, were studied from January to December in 1981 and from May to November in 2000. We investigated differences in activity patterns in relation to season, time of day, and age–sex classes of goats, and their possible causes. Since the goats spent the night sleeping (or resting) in caves or other sheltered sites, only diurnal activity budgets were considered. Activity patterns were very similar between the two study periods (from May to November). All age–sex classes of feral goats spent most of the daytime feeding in both years, especially during autumn and winter. Feral goats increased the percentage of daytime that they spent feeding and decreased their resting time from summer to autumn–winter in response to the decrease in available day length and, possibly, the decrease in forage quality and biomass. Feral goats on Rum had two or three daily peaks of feeding in summer, but showed no obvious daily feeding peaks in winter, although their percentage of feeding time remained relatively high throughout the daytime in winter. No significant differences in general activity budgets between adult males and females were found, but yearlings were found to spend more time feeding than adults and kids. Adult males spent more time in social activities than did other age–sex classes, and adult males sharply decreased the percentage of daytime that they spent feeding during rutting periods, which may have contributed to their higher mortality over the subsequent autumn and winter.


1997 ◽  
Vol 75 (9) ◽  
pp. 1372-1379 ◽  
Author(s):  
Marco Festa-Bianchet ◽  
Jon T. Jorgenson ◽  
Céline H. Bérubé ◽  
Christine Portier ◽  
William D. Wishart

In ungulates, body mass is often positively correlated with juvenile survival, but little is known of whether body mass affects survival of other age-classes. We studied two marked populations of bighorn sheep (Ovis canadensis) in Alberta, Canada, to determine if body mass affected the survival of different sex –age classes. Chest girth at weaning was correlated (P < 0.0001) with survival of bighorn lambs in the Sheep River population. In the Ram Mountain population, body mass in mid-September had a stronger effect upon survival than mass in early June, mass gain in summer, or mass loss in winter. Body mass at weaning was correlated with lamb survival (P = 0.004). In both study areas, relationships between size and survival of lambs were similar for the two sexes. At Ram Mountain, survival of yearling and adult males seemed to be independent of body mass. Light yearling females were less likely to survive than heavy yearling females. Among females aged 3 – 6 years, body mass had no effect on survival. Among females 7 years of age and older, mass in mid-September had a weak but significant (P = 0.03) effect on survival. Females were slightly lighter in mid-September in their last year of life than in the rest of their adult life. Maternal expenditure is unlikely to affect the survival of prime-age ewes, but may have a detrimental effect on the survival of older ewes.


1999 ◽  
Vol 26 (3) ◽  
pp. 263 ◽  
Author(s):  
Jane Melville ◽  
Roy Swain

We studied the home ranges of the alpine skink, Niveoscincus microlepidotus, in an alpine transition zone on Mt Wellington, Tasmania, over a 5-month period to examine seasonal patterns in the home-range characteristics of four male, four female and two sub-adult juvenile lizards. Home-range sizes and activity patterns within these were quantified. Adult males had significantly larger home ranges with more activity centres than adult females; most activity centres were clearly synonymous with basking sites and were defended by overt aggressive behaviour. Home ranges of males showed little overlap and no seasonal variation while those of femals were unusual amongst reptiles in showing extensive overlap and seasonal change in size. Ranges were smallest in spring when all females were pregnant and were smallest in summer when only one female was pregnant. Range overlap ensured that all females studied had potential access to at least two males. Juveniles had no defined home ranges and appeared to be transients.


Sports ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 30
Author(s):  
Jenny M. Mahoney ◽  
Brett R. Baughman ◽  
Ailish C. Sheard ◽  
Brandon J. Sawyer

The aim of the present study was to assess the validity of verification phase (VP) testing and a 3 min all-out test to determine critical power (CP) in males with obesity. Nine young adult males with a body mass index (BMI) ≥ 30 kg·m−2 completed a cycle ergometer ramp-style VO2max test, four randomized VP tests at 80, 90, 100, and 105% of maximum wattage attained during the ramp test, and a 3 min all-out test. There was a significant main effect for VO2max across all five tests (p = 0.049). Individually, 8 of 9 participants attained a higher VO2max (L/min) during a VP test compared to the ramp test. A trend (p = 0.06) was observed for VO2max during the 90% VP test (3.61 ± 0.54 L/min) when compared to the ramp test (3.37 ± 0.39 L/min). A significantly higher VO2max (p = 0.016) was found in the VP tests that occurred below 130% of CP wattage (N = 15, VO2max = 3.76 ± 0.52 L/min) compared to those that were above (N = 21, VO2max = 3.36 ± 0.41 L/min). Our findings suggest submaximal VP tests at 90% may elicit the highest VO2max in males with obesity and there may be merit in using % of CP wattage to determine optimal VP intensity.


2021 ◽  
Author(s):  
Kenta Uchida ◽  
Rachel Ng ◽  
Samuel A Vydro ◽  
Jennifer E Smith ◽  
Daniel T Blumstein

Abstract The benefits of dominance may not come without costs, particularly for males. For example, the “immunocompetence handicap hypothesis” states that males with enhanced mating success allocate resources to enhance reproductive output at a cost to their current health, whereas the “resource quality hypothesis” predicts that high-ranking males may benefit from increased reproduction and good health. While the predictions from each have been well tested in captive animals and in a variety of highly social primates, fewer studies have been carried out in free-living, facultatively social animals. Using adult male yellow-bellied marmots (Marmota flaviventer), we evaluated predictions of these hypotheses by examining the relationship between social rank and two health indicators–fecal corticosterone metabolite (FCM) levels, and neutrophil/lymphocyte (N/L) ratios–after accounting for variation explained by age, body mass, and seasonality. We found that higher-ranking males tended to have a lower N/L ratio (reflecting good health) than lower-ranking individuals, whereas FCM levels were not significantly related to rank. In addition, heavier male marmots had lower N/L ratios, while body mass was not associated with FCM levels. We also found that older adult males had lower FCM levels (reflecting less physiological stress) but higher N/L ratios than younger adults. Finally, we found that FCM levels decreased as the active season progressed and FCM levels were associated with the time of the day. Overall, our results suggest that socially-dominant male marmots enjoyed better, not worse health in terms of lower N/L ratios.


2019 ◽  
Vol 66 (4) ◽  
pp. 417-424
Author(s):  
Gregorio Moreno-Rueda ◽  
Abelardo Requena-Blanco ◽  
Francisco J Zamora-Camacho ◽  
Mar Comas ◽  
Guillem Pascual

Abstract Predation is one of the main selective forces in nature, frequently selecting potential prey for developing escape strategies. Escape ability is typically influenced by several morphological parameters, such as morphology of the locomotor appendices, muscular capacity, body mass, or fluctuating asymmetry, and may differ between sexes and age classes. In this study, we tested the relationship among these variables and jumping performance in 712 Iberian green frogs Pelophylax perezi from an urban population. The results suggest that the main determinant of jumping capacity was body size (explaining 48% of variance). Larger frogs jumped farther, but jumping performance reached an asymptote for the largest frogs. Once controlled by structural body size, the heaviest frogs jumped shorter distances, suggesting a trade-off between fat storage and jumping performance. Relative hind limb length also determined a small but significant percentage of variance (2.4%) in jumping performance—that is, the longer the hind limbs, the greater the jumping capacity. Juveniles had relatively shorter and less muscular hind limbs than adults (for a given body size), and their jumping performance was poorer. In our study population, the hind limbs of the frogs were very symmetrical, and we found no effect of fluctuating asymmetry on jumping performance. Therefore, our study provides evidence that jumping performance in frogs is not only affected by body size, but also by body mass and hind limb length, and differ between age classes.


Sign in / Sign up

Export Citation Format

Share Document