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

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 27 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.

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Effects of body size, population density, and maternal characteristics on age at first reproduction in bighorn ewes

Canadian Journal of Zoology ◽

10.1139/z93-344 ◽

1993 ◽

Vol 71 (12) ◽

pp. 2509-2517 ◽

Cited By ~ 110

Author(s):

Jon T. Jorgenson ◽

Marco Festa-Bianchet ◽

Mauro Lucherini ◽

William D. Wishart

Keyword(s):

Population Density ◽

Body Mass ◽

Age Distribution ◽

Ovis Canadensis ◽

The Body ◽

The Other ◽

Significant Interaction Effect ◽

Age At First Reproduction ◽

Maternal Characteristics ◽

First Reproduction

The factors affecting variation in age at first reproduction of bighorn ewes (Ovis canadensis) were investigated in two marked populations in Alberta. One population was studied for 20 years, the other for 11 years. As yearlings, females that lactated at 2 years of age were on average heavier and larger, and had longer horns than females that did not lactate at 2 years. However, there was wide overlap in body mass between early and late producers, and increases in body mass over the threshold for reproduction had little effect on the probability of early lambing. The body mass of females at 4 months of age explained less than half of the variance in female body mass at 1 year or at 15 months. In one population, the proportion of 2-year-old ewes lactating was not correlated with density and declined after a pneumonia epizootic. In the other population, the proportion of 2-year-old ewes lactating was higher during an experimental reduction of density, and dropped to near zero as density increased. There was a significant interaction effect of body mass and population density upon the probability that a ewe would lactate at 2 years of age. Independently of body mass, yearlings were less likely to lactate at 2 years of age at high population density than at low density. The number and age distribution of rams did not affect the proportion of 2-year-old ewes lactating. The mothers of lactating 2-year-olds were not older or heavier than the mothers of ewes that did not lactate at 2 years. Although some of the variation in age at first reproduction was due to differences in mass and population density, much of it remained unexplained and could be due to genetic factors.

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Body mass and survival of bighorn sheep

Canadian Journal of Zoology ◽

10.1139/z97-763 ◽

1997 ◽

Vol 75 (9) ◽

pp. 1372-1379 ◽

Cited By ~ 105

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.

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Sexual dimorphism in a marsupial: seasonal and lifetime differences in sex-specific mass

Australian Journal of Zoology ◽

10.1071/zo05060 ◽

2006 ◽

Vol 54 (1) ◽

pp. 45 ◽

Cited By ~ 6

Author(s):

J. L. Isaac

Keyword(s):

Sexual Dimorphism ◽

Body Mass ◽

Mass Gain ◽

Growth Patterns ◽

The Body ◽

Brushtail Possum ◽

Specific Mass ◽

Young Males ◽

The Common ◽

Common Brushtail Possum

Whereas sexual dimorphism in body mass is common in many vertebrates, the developmental mechanisms leading to diverging growth patterns between the sexes are poorly understood in mammals. In the present study, I investigate seasonal and lifetime differences in sex-specific mass in a marsupial, the common brushtail possum (Trichosurus vulpecula). From the age of 2 years, males were heavier than females, but significant dimorphism was evident only at the age of 4 years. Annual mass gain was greater in males than in females from 2 to 4 years of age. The body mass of both sexes fluctuated throughout the year, although patterns differed: females lost mass during lactation in winter, whereas males lost mass during the breeding season in later summer and autumn. The mass of a juvenile predicted its mass as an adult for males, but not females. Male-biased sexual dimorphism in mass of possums appears to arise through a combination of a greater rate and duration of mass gain in young males, and the diversion of somatic reserves away from growth and into reproduction in females.

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Using Astragalus to Model Body Mass, Habitat Preference, and Population Density of Prehistoric Bovid Duboisia santeng (Dubois, 1891) in Eastern Java island in The Early Pleistocene

10.20944/preprints202009.0522.v1 ◽

2020 ◽

Author(s):

Andri Wibowo

Keyword(s):

Population Density ◽

Body Mass ◽

Habitat Preference ◽

Regression Models ◽

The Body ◽

Early Pleistocene ◽

Large Herbivores ◽

Length Width ◽

Fossil Records ◽

The Relationship

Astragalus bone is one of the most important fossil records as it can reconstruct the prehistoric life. Respectively, this study aims to model the body mass, habitat preference, and population density of prehistoric bovid Duboisia santeng (Dubois 1891) in eastern Java island in the early Pleistocene. The astragali from 9 specimens were used to estimate the body mass and population density. Likewise regression models are used to analyze the relationship between astragalus lateral length, width, and body mass compared to the astragalus of extant Bovid species. The result revealed the body mass average was 60.3 kg (95%CI: 58.9-61.7) and this indicates the D. santeng belongs to large herbivores. While the population density was estimated at about 5.39 individuals per km2 (95% CI: 3.18-7.6).

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School bags and associated back pain

Journal of Health Sciences ◽

10.17532/jhsci.2017.510 ◽

2018 ◽

Vol 8 (1) ◽

pp. 10-19

Author(s):

Amra Mačak Hadžiomerović ◽

Amila Jaganjac ◽

Dijana Avdic ◽

Emira švraka ◽

Arzija Pašalić ◽

...

Keyword(s):

Back Pain ◽

Body Mass ◽

Sixth Grade ◽

Total Sample ◽

Cross Sectional Study ◽

The Body ◽

Fifth Grade ◽

Cross Sectional ◽

Negative Effect ◽

Type Of School

Introduction: The most common health problem associated with the negative effect of heavy school bags is back pain, and non-specific back pain is frequently observed in childhood. The prevalence of back pain in schoolchildren varies from 12% to 92%, depending on the age and affected region of the back. To prevent the occurrence of back pain in schoolchildren, the weight of school bag should not exceed 10% of the child’s body mass.Methods: This was a descriptive, cross-sectional study conducted in April 2017. We included 79 students of the fifth and sixth grade from the elementary school in Sarajevo. Information on the weight and type of school bag, method of carrying a school bag, and feelings of pain and tiredness due to school bag were obtained by questionnaire.Results: In the total sample, the majority of the students (64.6%) reported occasional back pain while carrying the bag, 20.3% of students reported no back pain, and 11.4% of students experienced frequent back pain. The mean school bag weight in the fifth grade was 4.01 ± 0.57 kg, and it was significantly higher (4.61 ± 0.86 kg) in the sixth grade. About 48.5% of the students in the fifth and 50% in the sixth grade carried school bags weighing more than 10% of the body mass. A higher mean weight of school bag was significantly more frequent in students who reported always feeling tired (11.03 ± 2.74%) compared to those who did not feel tired while carrying the school bag (8.41 ± 2%).Conclusions: Overall, more frequent occurrence of back pain and tiredness in schoolchildren was associated with heavier school bags (>10% of the body mass), and the occurrence of back pain due to school bag was related to gender (i.e., back pain was more common in girls compared to boys).

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Effect of Body Mass Index on Auricular Morphology and Auditory Functions

Ear Nose & Throat Journal ◽

10.1177/0145561319840579 ◽

2019 ◽

Vol 98 (7) ◽

pp. E81-E86 ◽

Cited By ~ 1

Author(s):

Mehmet Surmeli ◽

Ildem Deveci ◽

Hasan Canakci ◽

Mustafa Salih Canpolat ◽

Burak Karabulut ◽

...

Keyword(s):

Body Mass Index ◽

Soft Tissue ◽

Body Mass ◽

Significant Negative Correlation ◽

The Body ◽

Sulcus Angle ◽

Soft Tissue Thickness ◽

Negative Effect ◽

The Mean ◽

Auditory Functions

In this study, we aimed to investigate the relationship between the body mass index (BMI) and the morphometric properties of auricula and its acoustic gain characteristics. A total of 45 participants between 18 and 45 years of age were enrolled into the study. Participants’ height and weight measurements were recorded for the BMI calculation. On both sides, the morphometric properties of the auricula were measured and recorded. Additionally, the participants were subjected to multidirectional dynamic real ear measurements (REMs) to specify the intensity and frequency values of the maximum hearing gain. Participants consisted of 24 women and 21 men. The mean BMI was 23.42. The mean auricular area was 22.70 cm2. Statistically significant positive correlation was found between the auricular area and BMI ( r = 0.427, P = .03). The mean postauricular sulcus angle was 20.99°. The mastoid-helix distance was 16.07 mm. There was no statistically significant correlation between BMI level and postauricular sulcus angle and mastoid-helix distance ( P > .05). The mean dynamic REM measurement was evaluated. The maximum acoustic gain at anterior, lateral, and posterior vectorial stimulation was calculated as 20.9, 24.2, and 20.7 dB Sound Presure Level (SPL), respectively. Statistically significant negative correlation was found between the three directions acoustic gain level and BMI in the statistical examination ( r = −0.365, r = −0.386, r = −0.453, respectively, and P < .05 for all). The results of acoustic gain frequency were 2967.4, 2963, and 2934 Hz, respectively. There was no statistically significant correlation between acoustic gain frequency and BMI ( P > .05). When participants were grouped according to their BMI, participants with a BMI >25 had a statistically significantly bigger auricular area and lower maximum acoustic gain when compared with those with BMI <25 ( P < .05). We found that the auricular area increased with BMI. We think that this is related to soft tissue thickening of the auricula related to high BMI. In addition, we found that the acoustic gain level decreased inversely with BMI. We believe that the decrease in acoustic gain is due to the increase of acoustic resistance after the increase of soft tissue thickness. In conclusion, we think that BMI has a negative effect on auditory function according to findings in our study.

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Hydration status of Greco-Roman wrestlers in an authentic precompetition situation

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2012-0334 ◽

2013 ◽

Vol 38 (6) ◽

pp. 621-625 ◽

Cited By ~ 9

Author(s):

Vahur Ööpik ◽

Saima Timpmann ◽

Andres Burk ◽

Innar Hannus

Keyword(s):

Specific Gravity ◽

Body Mass ◽

Urine Osmolality ◽

Mass Gain ◽

The Body ◽

Urine Specific Gravity ◽

Hydration Status ◽

Greco Roman ◽

Reduced Body ◽

Body Mass Gain

We assessed the urinary indexes of hydration status of Greco-Roman wrestlers in an authentic precompetition situation at the time of official weigh-in (OWI). A total of 51 of 89 wrestlers competing in the Estonian Championship in 2009 donated a urine sample. Questionnaire responses revealed that 27 wrestlers (body mass losers (BMLs)) reduced body mass before the competition, whereas 24 wrestlers (those who do not lose body mass (n-BMLs)) did not. In 42 wrestlers, values of urine specific gravity ≥1.020 and urine osmolality ≥700 mOsmol·kg−1 revealed a hypohydrated status. The prevalence of hypohydration in the BMLs (96%) was higher than in the n-BMLs (67%) (χ2 = 7.68; p < 0.05). The prevalence of serious hypohydration (urine specific gravity >1.030) was 5.3 times greater (χ2 = 8.32; p < 0.05) in the BMLs than in the n-BMLs. In the BMLs, the extent of body mass gain during the 16-h recovery (2.5 ± 1.2 kg) was associated (r = 0.764; p < 0.05) with self-reported precompetition body mass loss (4.3 ± 2.0 kg) and exceeded the body mass gain observed in the n-BMLs (0.7 ± 1.2 kg; p < 0.05). We conclude that hypohydration is prevalent among Greco-Roman wrestlers at the time of OWI. The prevalence of hypohydration and serious hypohydration is especially high among wrestlers who are accustomed to reducing body mass before competition. These results suggest that an effective rehydration strategy is needed for Olympic-style wrestlers, and that changes in wrestling rules should be considered to reduce the prevalence of harmful body mass management behaviours.

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

Canadian Journal of Zoology ◽

10.1139/cjz-79-9-1661 ◽

2001 ◽

Vol 79 (9) ◽

pp. 1661-1670 ◽

Cited By ~ 27

Author(s):

Mylène LeBlanc ◽

Marco Festa-Bianchet ◽

Jon T. Jorgenson

Keyword(s):

Population Density ◽

Sexual Size Dimorphism ◽

Bighorn Sheep ◽

Ovis Canadensis ◽

Size Dimorphism

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Effect of High Intensity Interval and Continuous Swimming Training on Body Mass Adiposity Level and Serum Parameters in High-Fat Diet Fed Rats

The Scientific World JOURNAL ◽

10.1155/2016/2194120 ◽

2016 ◽

Vol 2016 ◽

pp. 1-8 ◽

Cited By ~ 7

Author(s):

Guilherme L. da Rocha ◽

Alex H. Crisp ◽

Maria R. M. de Oliveira ◽

Carlos A. da Silva ◽

Jadson O. Silva ◽

...

Keyword(s):

Body Mass ◽

High Fat Diet ◽

Interval Training ◽

Mass Gain ◽

The Body ◽

Standard Diet ◽

High Fat ◽

Continuous Training ◽

Body Mass Gain ◽

Training Standard

This study aimed to investigate the effects of interval and continuous training on the body mass gain and adiposity levels of rats fed a high-fat diet. Forty-eight male Sprague-Dawley rats were randomly divided into two groups, standard diet and high-fat diet, and received their respective diets for a period of four weeks without exercise stimuli. After this period, the animals were randomly divided into six groups (n=8): control standard diet (CS), control high-fat diet (CH), continuous training standard diet (CTS), continuous training high-fat diet (CTH), interval training standard diet (ITS), and interval training high-fat diet (ITH). The interval and continuous training consisted of a swimming exercise performed over eight weeks. CH rats had greater body mass gain, sum of adipose tissues mass, and lower serum high density lipoprotein values than CS. The trained groups showed lower values of feed intake, caloric intake, body mass gain, and adiposity levels compared with the CH group. No significant differences were observed between the trained groups (CTS versus ITS and CTH versus ITH) on body mass gains and adiposity levels. In conclusion, both training methodologies were shown to be effective in controlling body mass gain and adiposity levels in high-fat diet fed rats.

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