Huemul (Hippocamelus bisulcus) sociality at a periglacial site: sexual aggregation and habitat effects on group size

1999 ◽  
Vol 77 (7) ◽  
pp. 1083-1091 ◽  
Author(s):  
Alejandro Frid
Keyword(s):  
Group Size ◽  
Food Distribution ◽  
Sexually Dimorphic ◽  
Valley Bottom ◽  
Felis Concolor ◽  
Hippocamelus Bisulcus ◽  
Risk Of Predation ◽  
The Social ◽  
Young Of The Year ◽  
Behavioural Diversity

I studied social organisation of the huemul (Hippocamelus bisulcus), an Andean deer, during spring in coastal Chile. Analyses are based on individually recognised adults without young of the year. Deer that were not alone generally joined groups containing both sexes, and the proportion of time individuals spent in mixed-sex groups increased with the individual's mean group size. The absence of sexual segregation during spring is unusual among sexually dimorphic ungulates, and possibly reflected little variability in food distribution and (or) sex-specific predation pressure. Group sizes of individuals observed on multiple days increased strongly with distance from rocky slopes, and this relationship appeared to be unaffected by food distribution. These results suggest that the risk of predation, probably from cougars (Felis concolor) and (or) human hunters with dogs (Canis familiaris), is lower on rocky slopes than in valley-bottom habitats. Group sizes of individuals seen only once, however, were independent of distance from rocky slopes, possibly because these individuals were transients that did not integrate into the social structure of resident deer. The effect of rocky slopes on group sizes of individuals observed on multiple days is more characteristic of mountain Caprinae than of deer. The huemul is endangered, and its extinction could represent a substantial loss in the behavioural diversity of the Cervidae.

scholarly journals Social environment influences the relationship between genotype and gene expression in wild baboons

2013 ◽  
Vol 368 (1618) ◽  
pp. 20120345 ◽  
Author(s):  
Daniel E. Runcie ◽  
Ralph T. Wiedmann ◽  
Elizabeth A. Archie ◽  
Jeanne Altmann ◽  
Gregory A. Wray ◽  
...  
Keyword(s):  
Gene Expression ◽  
Individual Differences ◽  
Social Environment ◽  
Group Size ◽  
Early Life ◽  
Social Connectedness ◽  
Dominance Rank ◽  
Social Stressors ◽  
The Social ◽  
Wild Baboons

Variation in the social environment can have profound effects on survival and reproduction in wild social mammals. However, we know little about the degree to which these effects are influenced by genetic differences among individuals, and conversely, the degree to which social environmental variation mediates genetic reaction norms. To better understand these relationships, we investigated the potential for dominance rank, social connectedness and group size to modify the effects of genetic variation on gene expression in the wild baboons of the Amboseli basin. We found evidence for a number of gene–environment interactions (GEIs) associated with variation in the social environment, encompassing social environments experienced in adulthood as well as persistent effects of early life social environment. Social connectedness, maternal dominance rank and group size all interacted with genotype to influence gene expression in at least one sex, and either in early life or in adulthood. These results suggest that social and behavioural variation, akin to other factors such as age and sex, can impact the genotype–phenotype relationship. We conclude that GEIs mediated by the social environment are important in the evolution and maintenance of individual differences in wild social mammals, including individual differences in responses to social stressors.

Seasonal Habitat Use by Nubian Ibex (Capra Nubiana) Evaluated with Behavioral Indicators

2011 ◽  
Vol 57 (3) ◽  
pp. 223-246 ◽  
Author(s):  
Solomon A. Tadesse ◽  
Burt P. Kotler
Keyword(s):  
Group Size ◽  
Age Structure ◽  
Time Allocation ◽  
Environmental Variables ◽  
Time Budget ◽  
Habitat Type ◽  
Time Budgets ◽  
Behavioral Models ◽  
Risk Of Predation ◽  
Focal Observation

Nubian ibex (Capra nubiana) prefer steep terrain in their landscape to reduce risks of predation and human nuisance disturbances. They also use vigilance and time allocation to manage risk of predation. We studied time budgets and habitat selection of Nubian ibex to: (1) identify the habitat variables to which Nubian ibex were behaviorally responsive; (2) investigate how time budget responses of Nubian ibex were related to season, slope condition, group size, and sex-age structure; and (3) develop behavioral-based models that account for the variations in the behaviors of Nubian ibex across the landscape and seasons.To quantify time budgets, we took regular field observations on focal individuals of Nubian ibex classified according to their habitat, group size, sex, and age. For each focal observation, we quantified environmental variables that were thought to influence the behavioral responses of ibex. Then, we developed behavioral models by correlating the proportion of behaviors measured in focal animal observations to the influential environmental variables. The behaviors of Nubian ibex significantly varied with sex and age structure, season, habitat type, and slope conditions. Adult females are more vigilant than adult male ibex, especially in the spring. This correlates with breeding and nursing activities. Based on the characteristics of the habitat, ibex behave to minimize risks of predation and human nuisance disturbances while maximizing their food intake.

scholarly journals Prenatal Risk for Autism Spectrum Disorder (ASD): Fetal Cortisol Exposure Predicts Child ASD Symptoms

2018 ◽  
Vol 7 (2) ◽  
pp. 349-361 ◽  
Author(s):  
Sheena Ram ◽  
Mariann A. Howland ◽  
Curt A. Sandman ◽  
Elysia Poggi Davis ◽  
Laura M. Glynn
Keyword(s):  
Autism Spectrum Disorder ◽  
Developmental Disorder ◽  
Maternal Plasma ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Sexually Dimorphic ◽  
Fetal Exposure ◽  
Prospective Longitudinal Study ◽  
The Social ◽  
Prospective Longitudinal

The etiology of autism spectrum disorder (ASD) is multifactorial, complex, and likely involves interactions among genetic, epigenetic, and environmental factors. With respect to environmental influences, a growing literature implicates intrauterine experiences in the origin of this pervasive developmental disorder. In this prospective longitudinal study, we examined the hypothesis that fetal exposure to maternal cortisol may confer ASD risk. In addition, because ASD is four times more prevalent in males than in females, and because sexually dimorphic responses to intrauterine experiences are commonly observed, we examined whether or not any associations differ by fetal sex. Maternal plasma cortisol was measured at 15, 19, 25, 31, and 37 weeks’ gestation in a sample of 84 pregnant women. ASD symptoms were assessed in their 5-year-old children with the Social Communication Questionnaire (SCQ). Fetal exposure to lower levels of maternal cortisol was associated with higher levels of ASD symptoms only among boys. The observed hypocortisolemic profile exhibited by these mothers may indicate a risk factor that precedes the stress of caregiving for a child with ASD and may not be solely a consequence of the stress of caregiving, as previously thought. These findings confirm the value of examining prenatal hormone exposures as predictors of ASD risk and support the premise that altered prenatal steroid exposures may play a role in the etiology of ASD.

scholarly journals Social Group Size and Shelter Availability Influence Individual Metabolic Traits in a Social Fish

2021 ◽  
Author(s):  
Emmanuelle Chrétien ◽  
Daniel Boisclair ◽  
Steven J Cooke ◽  
Shaun S Killen
Keyword(s):  
Metabolic Rate ◽  
Group Size ◽  
Social Group ◽  
Physiological Traits ◽  
Metabolic Rates ◽  
Night Time ◽  
The Social ◽  
Before And After ◽  
Social Treatment ◽  
Shelter Availability

Abstract Group living is widespread among animal species and yields both costs and benefits. Presence of conspecifics can restrict or enhance the expression of individual behaviour, and the recent social environment is thought to affect behavioural responses in later contexts, even when individuals are alone. However, little is known about how social group size influences the expression of individual physiological traits, including metabolic rates. There is some evidence that shoaling can reduce fish metabolic rates but this variable may be affected by habitat conditions such as shelter availability via density-dependent processes. We investigated how social group size and shelter availability influence Eurasian minnow Phoxinus phoxinus metabolic rates estimated by respirometry. Respirometry trials were conducted on fish in isolation before and after they were housed for three weeks in a social treatment consisting in a specific group size (n = 4 or 8) and shelter availability (presence or absence of plant shelter in the experimental tank). Plant shelter was placed over respirometers for half of the duration of the respirometry trials, allowing estimation of minimum day-time and night-time metabolic rates in both conditions (in the presence or absence of plant shelter). Standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope (AS) were also estimated over the entire trial. Minimum day-time and night-time metabolic rates estimated while in presence of plant shelter were lower than when estimated in absence of plant shelter, both before and after individuals were housed in their social treatment. After the social treatment, SMR were higher for fish that were held in groups of four as compared to that of fish held in groups of eight while MMR showed no difference. Plant shelter availability during the social treatments did not influence SMR or MMR. Our results suggest that social group size may directly influence energy demands of individuals, highlighting the importance of understanding the role of group size on variations in physiological traits associated with energy expenditure.

scholarly journals Social learning strategies regulate the wisdom and madness of interactive crowds

2018 ◽  
Author(s):  
Wataru Toyokawa ◽  
Andrew Whalen ◽  
Kevin N. Laland
Keyword(s):  
Social Learning ◽  
Learning Strategies ◽  
Group Size ◽  
Collective Intelligence ◽  
Collective Wisdom ◽  
The Social ◽  
Challenging Tasks ◽  
Task Uncertainty ◽  
The Individual ◽  
Social Learning Strategies

AbstractWhy groups of individuals sometimes exhibit collective ‘wisdom’ and other times maladaptive ‘herding’ is an enduring conundrum. Here we show that this apparent conflict is regulated by the social learning strategies deployed. We examined the patterns of human social learning through an interactive online experiment with 699 participants, varying both task uncertainty and group size, then used hierarchical Bayesian model-ftting to identify the individual learning strategies exhibited by participants. Challenging tasks elicit greater conformity amongst individuals, with rates of copying increasing with group size, leading to high probabilities of herding amongst large groups confronted with uncertainty. Conversely, the reduced social learning of small groups, and the greater probability that social information would be accurate for less-challenging tasks, generated ‘wisdom of the crowd’ effects in other circumstances. Our model-based approach provides evidence that the likelihood of collective intelligence versus herding can be predicted, resolving a longstanding puzzle in the literature.

Spatial variability in the social organisation of the yellow-bellied glider (Petaurus australis) near Ravenshoe, north Queensland

2001 ◽  
Vol 49 (4) ◽  
pp. 397 ◽  
Author(s):  
Ross L. Goldingay ◽  
Darren G. Quin ◽  
Sue Churchill
Keyword(s):  
Adult Female ◽  
Social System ◽  
Dominant Male ◽  
Female Group ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Adult Females ◽  
The Social ◽  
Natal Home ◽  
Petaurus Australis

A detailed study was conducted over a 12-month period of 10 yellow-bellied glider groups at Nitchaga Creek in north Queensland. Adult gliders were sexually dimorphic in body size and were characterised by yellow ventral fur, which is consistent with southern populations. Gliders lived in groups of 3–6 individuals that occupied exclusive areas of about 50 ha. The structure of glider groups varied enormously: five contained one adult pair, three contained one adult male and 2–3 adult females, and two initially contained 2–3 adult males and one adult female but then persisted as bachelor groups after the death or disappearance of the adult female. Group size changed during the year as offspring matured and as individuals died. One male glider dispersed about 1 km from its natal home-range and became the dominant male in a nearby group. Young were born throughout the year, with a peak in the number of pouch-young in June. This study has confirmed the highly variable social system of the yellow-bellied glider, which appears to be mediated by local resource abundance.

The Social Organisation of the Dusky Moorhen, Gallinula tenebrosa Gould (Aves : Rallidae)

1980 ◽  
Vol 7 (1) ◽  
pp. 103 ◽  
Author(s):  
ST Garnett
Keyword(s):  
Group Size ◽  
Sexual Behaviour ◽  
Social Organisation ◽  
Nest Sites ◽  
The Social ◽  
Free Ranging

A population of dusky moorhens was studied between October 1974 and December 1976. Moorhens were present in the study area throughout the year, existing predominantly in free-ranging flocks in May and June and tending to form territorial groups of from two to seven birds from July to April. In a group there were from one to three males per female; all males copulated with all females. Groups formed in July were predominantly of experienced adults and did not cease territoriality until April; those formed later, in September, were predominantly of immatures and tended to cease territoriality in March. The former had larger territories with more reeds, less sexual behaviour although more frequent successful coition, and a higher productivity than the latter. Productivity did not increase with group size although those with more than four birds lost twice as many eggs as smaller groups. It is unlikely that members of a group are related. The most frequent group size was four and it is postulated that groups of this size produce the most young. The skewed ratio in groups may result from the scarcity of nest sites, which limits the number of females per group.

scholarly journals Vigilance behavior of pyrenean chamois Rupicapra pyrenaica pyrenaica: Effect of sex and position in the herd

2010 ◽  
Vol 56 (2) ◽  
pp. 232-237 ◽  
Author(s):  
Antoni Dalmau ◽  
Alfred Ferret ◽  
Xavier Manteca
Keyword(s):  
Social Interactions ◽  
Group Size ◽  
Group Living ◽  
Advantages And Disadvantages ◽  
Rupicapra Pyrenaica ◽  
Vigilance Behavior ◽  
Focal Animal ◽  
Risk Of Predation ◽  
Pyrenean Chamois ◽  
Optimal Group Size

Abstract The Pyrenean chamois Rupicapra pyrenaica pyrenaica is a mountain-dwelling ungulate with an extensive presence in open areas. Optimal group size results from the trade off between advantages (a reduction in the risk of predation) and disadvantages (competition between members of the herd) of group living. In addition, advantages and disadvantages of group living may vary depending on the position of each individual within the herd. Our objective was to study the effect of central vs. peripheral position in the herd on feeding and vigilance behavior in male and female Pyrenean chamois and to ascertain if a group size effect existed. We used focal animal sampling and recorded social interactions when a focal animal was involved. With males, vigilance rate was higher in the central part of the group than at the periphery, probably due to a higher density of animals in the central part of the herd and a higher probability of being disturbed by conspecifics. With females, vigilance rate did not differ according to position in the herd. Females spent more time feeding than males, and males showed a higher frequency of the vigilance behavior than females. We did not observe a clear relationship between group size and vigilance behavior. The differences in vigilance behavior might be due to social interactions.

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