Modelling sexual segregation in ungulates: effects of group size, activity budgets and synchrony

2002 ◽  
Vol 64 (6) ◽  
pp. 909-914 ◽  
Author(s):  
K.E Ruckstuhl ◽  
H Kokko
Keyword(s):  
Group Size ◽  
Sexual Segregation ◽  
Activity Budgets

scholarly journals Male group size, female distribution and changes in sexual segregation by Roosevelt elk

PLoS ONE ◽  
2017 ◽  
Vol 12 (11) ◽  
pp. e0187829 ◽  
Author(s):  
Leah M. Peterson ◽  
Floyd W. Weckerly
Keyword(s):  
Group Size ◽  
Sexual Segregation ◽  
Male Group

Sexual segregation in bison: a test of multiple hypotheses

Behaviour ◽  
2005 ◽  
Vol 142 (7) ◽  
pp. 897-927 ◽  
Author(s):  
Eric W. Schaad ◽  
David S. Wiseman ◽  
Royce R. Huber ◽  
Michael S. Mooring ◽  
Dominic D. Reisig ◽  
...  
Keyword(s):  
Body Size ◽  
Predation Risk ◽  
Sexual Segregation ◽  
Bison Bison ◽  
Sexually Dimorphic ◽  
Activity Budgets ◽  
Single Sex ◽  
Multiple Hypotheses ◽  
Mixed Groups ◽  
Large Groups

AbstractSexual segregation, in which males and females form separate groups for most of the year, is common in sexually dimorphic ungulates. We tested multiple hypotheses to explain sexual segregation in bison (Bison bison) at National Bison Range, Montana and Fort Niobrara National Wildlife Refuge, Nebraska during June-August of 2002-2003. Fieldwork involved use of GPS to record space use by segregated groups, vegetation transects to measure forage availability, fecal analyses to document diet composition and quality, and behavioural observations to characterize activity budgets. During sexual segregation, males in bull groups used areas with greater per capita abundance of forage, higher proportion of weeds, and less nutritious grasses (as indicated by lower % fecal nitrogen) compared with females in cow or mixed groups. However, there was no difference between the sexes in activity budgets, predation risk factors, or distance to water. Single-sex bull groups were no more synchronized in activity than mixed groups. These results support the 'sexual dimorphism-body size hypothesis', which proposes that males segregate from females because their larger body size requires more abundant forage, while longer ruminal retention permits efficient use of lower-quality forage. The gastrocentric model, based on the digestive physiology and foraging requirements of dimorphic ungulates, supplies the most likely proximate mechanism for bison sexual segregation. Our results would also partly support the 'reproductive strategy-predation risk hypothesis' if females form large groups to reduce predation risk. The predictions of the 'activity budget hypothesis' were not supported for bison.

scholarly journals Sexual segregation in human conversations

Behaviour ◽  
2016 ◽  
Vol 153 (1) ◽  
pp. 1-14 ◽  
Author(s):  
R.I.M. Dunbar
Keyword(s):  
Sex Differences ◽  
Group Size ◽  
Social Group ◽  
Census Data ◽  
Social Groups ◽  
Characteristic Size ◽  
Sexual Segregation ◽  
Fractal Pattern ◽  
Single Sex ◽  
Conversational Style

Human conversation groups have a characteristic size limit at around four individuals. Although mixed-sex social groups can be significantly larger than this, census data on casual social groups suggest that there is a fractal pattern of fission in conversations when social group size is a multiple of this value. This study suggests that, as social group size increases beyond four, there is a tendency for sexual segregation to occur resulting in an increasing frequency of single-sex conversational subgroups. It is not clear why conversations fragment in this way, but a likely explanation is that sex differences in conversational style result in women (in particular) preferring to join all-female conversations when a social group is large enough to allow this.

Activity budgets and group size of caribou during spring migration

1987 ◽  
Vol 65 (1) ◽  
pp. 164-168 ◽  
Author(s):  
Laurel S. Duquette ◽  
David R. Klein
Keyword(s):  
Group Size ◽  
Social Facilitation ◽  
Early Spring ◽  
Spring Migration ◽  
Activity Budgets ◽  
Average Proportion ◽  
Study Sites ◽  
Migratory Movements ◽  
Dominant Activity ◽  
Walking Time

Activity budgets and group size of caribou were described throughout the early spring migration in 1982 and 1983. Pregnant cows were the predominant cohort under observation. Activity budgets and group size of migrating caribou are compared with data from nonmigrating caribou and reindeer to test the hypothesis that the spring migration of pregnant cow caribou will occur with minimal disruption of the normal grazing pattern to ensure maintenance of body condition. The average proportion of time migrating caribou spent feeding, lying, standing, and walking was 61, 28, 1, and 9%, respectively, in 1982 and 64, 24, 1, and 11%, respectively, in 1983. Grazing was consistently the dominant activity throughout migration while lying time was negatively correlated with walking time. Migrating caribou spent more time grazing and walking and less time standing and lying than nonmigrating caribou and reindeer during this season. Discrete caribou groups were difficult to identify because mixing of caribou between groups was common. Groups were identifiable at four study sites and group size ranged from 8 to 393 caribou. At three study sites, caribou were associated with aggregations of 500+ animals. Large social aggregations may be important for stimulating migratory movements through the process of social facilitation.

scholarly journals Activity Budgets and Sexual Segregation in African Elephants (Loxodonta africana)

2008 ◽  
Vol 89 (2) ◽  
pp. 467-476 ◽  
Author(s):  
Graeme Shannon ◽  
Bruce R. Page ◽  
Robin L. Mackey ◽  
Kevin J. Duffy ◽  
Rob Slotow
Keyword(s):  
Loxodonta Africana ◽  
Sexual Segregation ◽  
African Elephants ◽  
Activity Budgets

An ecological basis for large group size in Colobus angolensis in the Nyungwe Forest, Rwanda

2001 ◽  
Vol 39 (1) ◽  
pp. 83-92 ◽  
Author(s):  
Cheryl Fimbel ◽  
Amy Vedder ◽  
Ellen Dierenfeld ◽  
Felix Mulindahabi
Keyword(s):  
Group Size ◽  
Large Group ◽  
Colobus Angolensis ◽  
Ecological Basis
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