Body mass and survival of bighorn sheep

1997 ◽  
Vol 75 (9) ◽  
pp. 1372-1379 ◽  
Author(s):  
Marco Festa-Bianchet ◽  
Jon T. Jorgenson ◽  
Céline H. Bérubé ◽  
Christine Portier ◽  
William D. Wishart
Keyword(s):  
Body Mass ◽  
Adult Life ◽  
Mass Gain ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Adult Males ◽  
Age Classes ◽  
River Population ◽  
Maternal Expenditure ◽  
Chest Girth

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.

The development of sexual dimorphism: seasonal and lifetime mass changes in bighorn sheep

1996 ◽  
Vol 74 (2) ◽  
pp. 330-342 ◽  
Author(s):  
Marco Festa-Bianchet ◽  
Wendy J. King ◽  
Jon T. Jorgenson ◽  
Kirby G. Smith ◽  
William D. Wishart
Keyword(s):  
Sexual Dimorphism ◽  
Mass Loss ◽  
Mass Gain ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Age Classes ◽  
Male And Female ◽  
Absolute Mass ◽  
June July ◽  
Mass Accumulation

Individually marked bighorn sheep (Ovis canadensis) were monitored to determine how seasonal and lifetime changes in mass affected the development of sexual dimorphism, and to what extent mass at a given age could predict mass of the same sheep at a later age. We trapped sheep from late May to early October each year from 1971 to 1985 in a population artificially kept at low density. Lambs and yearlings gained mass linearly from June to September, while absolute mass gain of older sheep was faster in June–July than in August–September. Males gained more mass than females each summer up to at least 3 years of age. Relative summer mass gain, calculated as a proportion of body mass at the beginning of June, was the same for male and female lambs but was greater for male than for female yearlings and 2-year-olds. With the exception of lambs, all age-classes lost mass during winter. Mass loss between September 15 and June 5 was greater for females than for males, possibly because ewes lost mass through parturition in late May. For both sexes, asymptotic mass was not reached until at least 7 years of age. Mass at 4 and 12 months of age was correlated with mass at 4 years. For all sex–age classes, mass on June 5 was negatively correlated with summer mass gain. For lambs and yearlings, winter mass loss was positively correlated with mass on September 15. Our results suggest that at low population density, sheep optimize rather than maximize summer mass accumulation. Most sexual dimorphism develops after weaning, through faster mass gain by males than by females at 1 and 2 years of age and possibly a longer season of mass gain each year for males than for females after females reach puberty.

Sexual size dimorphism in bighorn sheep (Ovis canadensis): effects of population density

2001 ◽  
Vol 79 (9) ◽  
pp. 1661-1670 ◽  
Author(s):  
Mylène LeBlanc ◽  
Marco Festa-Bianchet ◽  
Jon T Jorgenson
Keyword(s):  
Population Density ◽  
Body Mass ◽  
Phenotypic Expression ◽  
Mass Gain ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
The Body ◽  
Young Males ◽  
Negative Effect ◽  
Female Body Mass

Sexual dimorphism is an important characteristic of many mammals, but little is known about how environmental variables may affect its phenotypic expression. The relationships between population size, body mass, seasonal mass changes, and sexual mass dimorphism were investigated using 22 years of data on individually marked bighorn sheep (Ovis canadensis) on Ram Mountain, Alberta. The number of adult ewes was artificially maintained low from 1972 to 1981 and then allowed to increase. The body mass of males from 0 to 7 years of age was negatively affected by population density. Female body mass was negatively affected by population density up to 2 years of age. As the number of ewes increased, sexual mass dimorphism of sheep aged 2–7 years declined. Population density had a negative effect on seasonal mass changes of young males and females. Density also had a weak but significant positive effect on yearly mass gain of 2-year-old females, suggesting compensatory growth. Females appear to compensate for resource shortages early in life, while males show a lifelong negative effect. We suggest that these sexual differences are due to the greater flexibility of resource allocation to growth or reproduction by females than by males.

Maternal Thyroid Hormone Deficiency During Gestation and Lactation Alters Metabolic and Thyroid Programming of the Offspring in the Adult Stage

2019 ◽  
Vol 51 (06) ◽  
pp. 381-388 ◽  
Author(s):  
Jorge Tapia-Martínez ◽  
Alejandra Paola Torres-Manzo ◽  
Margarita Franco-Colín ◽  
Marisol Pineda-Reynoso ◽  
Edgar Cano-Europa
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Body Mass ◽  
Adult Life ◽  
Mass Gain ◽  
Hormone Deficiency ◽  
Body Mass Gain ◽  
Maternal Thyroid

AbstractEnvironmental stimuli during critical developmental stages establish long-term physiological and structural patterns that “program” health during adult life. Little is known about how alterations in hormonal supply might have consequences in metabolic and thyroid programming. This work aims to prove that alterations in the supply of thyroid hormones during gestation and lactation have long-term consequences in the metabolic and thyroid programming of the offspring. Female Wistar rats were divided into euthyroid, hypothyroid, and hypothyroid with 20 μg/day of s.c. thyroxine (T4), replacement wet nurses. Rats were mating, and after birth, pups were grouped according to their wet nurses group. Milk quality of wet nurses was assessed on days 7, 14, and 21. Body mass gain and energy intake of the offspring were monitored for 28 weeks after weaning. At sacrifice, we extracted and weighed their thyroid gland and adipose reserves, and collected blood to measure its metabolic and thyroid profiles. Hypothyroid wet nurses presented a persistent low quality of milk, while both male and female hypothyroid offspring presented lower body mass gain, higher blood glucose, dyslipidemia, hyperinsulinemia, and hyperleptinemia, as well as lower total adipose reserves, but higher visceral reserve, diminished T3 and T4 concentrations, and lower weight of thyroid gland. Thyroxine replacement prevented all changes in both wet nurses and pups. We conclude that maternal thyroid hormone deficiency during congenital and lactation stages alters the metabolic and thyroid programming of the offspring, while the reestablishment of maternal thyroid status during critical periods of development can prevent these alterations.

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
Keyword(s):  
Body Mass ◽  
Seasonal Changes ◽  
Activity Patterns ◽  
Seasonal Patterns ◽  
Feeding Time ◽  
Adult Males ◽  
Costs Of Reproduction ◽  
Age Classes ◽  
Male Adult ◽  
Lagostomus Maximus

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.

Bighorn sheep in winter: do rams maximize reproductive fitness by spatial and habitat segregation from ewes?

1977 ◽  
Vol 55 (11) ◽  
pp. 1802-1810 ◽  
Author(s):  
Valerius Geist ◽  
R. G. Petocz
Keyword(s):  
Habitat Selection ◽  
Social Behaviour ◽  
Habitat Preference ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Habitat Segregation ◽  
Adult Males ◽  
Behavioural Types ◽  
Wintering Area ◽  
Continuous Range

In bighorn sheep (Ovis canadensis canadensis) the segregation of adult males from females is explained by two hypotheses: first, males exhausted by the rut must avoid females to escape culling predators; second, males ought to segregate from females in such a fashion as to minimize competition and disturbance for the mothers of their prospective offspring. Only the second hypothesis coincides closely with previously known facts about sheep. It predicts that on common winter ranges adult males ought to minimize competition for females by segregating spatially and by habitat selection. This was verified. Although both sexes may occupy a continuous range, they concentrate in different areas; rams have a greater preference for open slopes and ewes for cliffs. This segregation held true even in a winter with exceptional snow depths. Sheep occupied the wintering area in a similar manner in successive years; females were found to be more affected by snow than males. In their habitat preference, rams and ewes acted in accordance with their behavioural types, much as was found to be true for their social behaviour.

Roads, routes and rams: does sexual segregation contribute to anthropogenic risk in a desert-dwelling ungulate?

2016 ◽  
Vol 43 (5) ◽  
pp. 380 ◽  
Author(s):  
Vernon C. Bleich ◽  
Jericho C. Whiting ◽  
John G. Kie ◽  
R. Terry Bowyer
Keyword(s):  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Sexual Segregation ◽  
Adult Males ◽  
Large Mammals ◽  
Male And Female ◽  
Use Of Resources ◽  
Core Areas ◽  
Males And Females ◽  
Time Of Year

Context Little is known about the consequences of sexual segregation (differential use of resources by the sexes outside of the mating season) for the conservation of large mammals. Roadways (i.e. the strip of land over which a road or route passes) are ubiquitous around the world, and are a major cause of wildlife mortality, as well as habitat loss and fragmentation. Many populations of bighorn sheep (Ovis canadensis) occur at low densities and in a metapopulation structure. Roadways could affect movements of males and females differentially, an outcome that has not been considered previously. Aims We investigated the propensity of the sexes to cross a paved two-lane road and a single-lane, maintained dirt route and predicted that adult males, because of their life-history characteristics, would cross those roadways more often than females. Methods We investigated movements of male and female bighorn sheep from 1986 to 1990. We used a fixed-wing aircraft with an H-antenna on each wing strut to locate individuals each week from October 1986 to December 1990. We estimated the degree of overlap among 50% core areas of use by males and females with the utilisation distribution overlap index (UDOI). Key results We relocated male and female bighorn sheep on 948 occasions during sexual aggregation and on 1951 occasions during sexual segregation. More males than females were likely to cross both types of roadways during segregation, and the dirt route during aggregation. Propensity of males and females to cross roadways was strongly influenced by time of year (i.e. whether the period of sexual aggregation or sexual segregation). The lowest overlap in 50% core areas was between females and males during periods of segregation (UDOI = 0.1447). Conclusions More males than females crossed Kelbaker Road and the unnamed dirt route during segregation, as well as the unnamed route during aggregation. Both of those features could affect males more than females, and could result in reductions in the use of habitat or increased mortality of bighorn sheep from vehicle collisions as a result of spatial segregation of the sexes. Implications During environmental review, biologists should consider sexual segregation when assessing potential anthropogenic effects on movements of bighorn sheep. Biologists also should consider sexual segregation and how roadways, even lightly traveled routes, affect movements of male and female ungulates differently before manipulating habitat, translocating animals, or constructing or modifying roadways.

Does testosterone or coloration affect growth rates of adult males of the lizard Psammodromus algirus?

2000 ◽  
Vol 78 (8) ◽  
pp. 1463-1467 ◽  
Author(s):  
Alfredo Salvador ◽  
José P Veiga
Keyword(s):  
Body Mass ◽  
Breeding Season ◽  
Mass Gain ◽  
Reproductive Period ◽  
The Body ◽  
Adult Males ◽  
Psammodromus Algirus ◽  
Ornamental Traits ◽  
Breeding Coloration

Elevation of circulating testosterone levels during the breeding season stimulates the development of breeding coloration and favors traits that maximize reproductive success, but it may have several costs. Retardation of growth by testosterone has been proposed as one of these costs to males of long-lived species. We examine the results of a field experiment on the short-term (within the breeding season) and long-term (1 year) effects of heightening levels of testosterone on the growth of males of the lacertid lizard Psammodromus algirus. Testosterone did not affect the mass gain of males during the reproductive period or between years. The between-years increase in snout-vent length in testosterone-supplemented males tended to be less than in control individuals. Within-season individual mass gain was mainly determined by body mass at emergence: the lower the body mass the higher the mass gain. Our results do not support the idea that the production of ornamental traits limits growth, as the negative correlation between degree of head coloration and mass gain disappeared when body mass was controlled for.

scholarly journals Genomic analysis of morphometric traits in bighorn sheep using the Ovine Infinium® HD SNP BeadChip

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4364 ◽  
Author(s):  
Joshua M. Miller ◽  
Marco Festa-Bianchet ◽  
David W. Coltman
Keyword(s):  
Sexual Selection ◽  
Body Mass ◽  
Genetic Basis ◽  
Genome Wide Association Study ◽  
Molecular Ecology ◽  
Genomic Analysis ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Morphometric Traits ◽  
A Genome

Elucidating the genetic basis of fitness-related traits is a major goal of molecular ecology. Traits subject to sexual selection are particularly interesting, as non-random mate choice should deplete genetic variation and thereby their evolutionary benefits. We examined the genetic basis of three sexually selected morphometric traits in bighorn sheep (Ovis canadensis): horn length, horn base circumference, and body mass. These traits are of specific concern in bighorn sheep as artificial selection through trophy hunting opposes sexual selection. Specifically, horn size determines trophy status and, in most North American jurisdictions, if an individual can be legally harvested. Using between 7,994–9,552 phenotypic measures from the long-term individual-based study at Ram Mountain (Alberta, Canada), we first showed that all three traits are heritable (h2 = 0.15–0.23). We then conducted a genome-wide association study (GWAS) utilizing a set of 3,777 SNPs typed in 76 individuals using the Ovine Infinium® HD SNP BeadChip. We found suggestive association for body mass at a single locus (OAR9_91647990). The absence of strong associations with SNPs suggests that the traits are likely polygenic. These results represent a step forward for characterizing the genetic architecture of fitness related traits in sexually dimorphic ungulates.

scholarly journals Nestling Development of Ring-necked Parakeets (Psittacula krameri) in a Nest Box Population

2013 ◽  
Vol 6 (1) ◽  
pp. 9-24 ◽  
Author(s):  
Michael P. Braun ◽  
Michael Wink
Keyword(s):  
Natural Selection ◽  
Body Mass ◽  
Tail Length ◽  
Mass Gain ◽  
Hatching Asynchrony ◽  
Adult Males ◽  
Psittacula Krameri ◽  
Body Mass Gain ◽  
Nestling Development ◽  
Chick Development

Chick development of a population of non-native Ring-necked Parakeets (Psittacula krameri) (RNP) has been investigated between 2006 and 2008 in Heidelberg, Germany. In parrots hatching asynchrony is common. RNP chicks are under natural selection to fledge synchronously with their siblings, as parents return less often to the nest after the first chick has fledged and remaining chicks may starve. Female nestlings apparently outperform the males by about one d in body mass gain, but also had higher measurements in tarsus, wing and tail growth. This was unexpected as adult males are generally larger than females. First-hatched chicks showed lowest biometrical values as compared to their younger siblings in several characters like body mass gain, bill, wing, and tail length. This feature may contribute to a synchronization of fledging in an otherwise asynchronous brood.

scholarly journals Determining the Optimal Workrate for Cycle Ergometer Verification Phase Testing in Males with Obesity

Sports ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 30
Author(s):  
Jenny M. Mahoney ◽  
Brett R. Baughman ◽  
Ailish C. Sheard ◽  
Brandon J. Sawyer
Keyword(s):  
Body Mass Index ◽  
Young Adult ◽  
Body Mass ◽  
Critical Power ◽  
Cycle Ergometer ◽  
Adult Males ◽  
Ramp Test ◽  
Young Adult Males ◽  
Main Effect ◽  
Vo2max Test

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.

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