Social organization in the Egyptian mongoose: group size, spatial behaviour and inter-individual contacts in adults

1993 ◽  
Vol 45 (5) ◽  
pp. 917-925 ◽  
Author(s):  
F. Palomares ◽  
M. Delibes
1981 ◽  
Vol 59 (4) ◽  
pp. 639-652 ◽  
Author(s):  
W. Don Bowen

The foraging ecology and social organization of coyotes, Canis latrans, were studied in Jasper National Park, Alberta, from 1974 to 1977. Diet was determined from analysis of 1967 feces. In summer when rodents (43%) and neonatal cervids (19%) were the major foods, average group size in the population was 1.4 (n = 339 observations), whereas in winter when large ungulates dominated the diet (67%) average group size rose to 2.0 (n = 798). This pattern was also evident for two packs where mean group size rose from 1.5 in summer to 3.1 in winter with the incorporation of pups into the pack. The percentage of mule deer in the winter diet varied directly with group size. Packs were more successful than pairs or single coyotes in catching mule deer. In contrast, the percentage of elk in the winter diet was independent of group size. Since elk were scavenged, their occurrence in the winter diet was primarily a function of the number dying within each coyote territory. Pairs and packs defended ungulate carcasses and used these clumped resources more effectively than single coyotes. I conclude that group foraging increases the feeding efficiency of coyotes in Jasper. A comparison of the present findings with the results of the other coyote studies indicates that variation in the average size of prey eaten is an important factor determining group size and structure of coyote populations.


2015 ◽  
Vol 282 (1819) ◽  
pp. 20151971 ◽  
Author(s):  
Arne Jungwirth ◽  
Michael Taborsky

Cooperative breeders serve as a model to study the evolution of cooperation, where costs and benefits of helping are typically scrutinized at the level of group membership. However, cooperation is often observed in multi-level social organizations involving interactions among individuals at various levels. Here, we argue that a full understanding of the adaptive value of cooperation and the evolution of complex social organization requires identifying the effect of different levels of social organization on direct and indirect fitness components. Our long-term field data show that in the cooperatively breeding, colonial cichlid fish Neolamprologus pulcher , both large group size and high colony density significantly raised group persistence. Neither group size nor density affected survival at the individual level, but they had interactive effects on reproductive output; large group size raised productivity when local population density was low, whereas in contrast, small groups were more productive at high densities. Fitness estimates of individually marked fish revealed indirect fitness benefits associated with staying in large groups. Inclusive fitness, however, was not significantly affected by group size, because the direct fitness component was not increased in larger groups. Together, our findings highlight that the reproductive output of groups may be affected in opposite directions by different levels of sociality, and that complex forms of sociality and costly cooperation may evolve in the absence of large indirect fitness benefits and the influence of kin selection.


2020 ◽  
Vol 287 (1928) ◽  
pp. 20200693 ◽  
Author(s):  
Cedric Perret ◽  
Emma Hart ◽  
Simon T. Powers

A manifest trend is that larger and more productive human groups shift from distributed to centralized decision-making. Voluntary theories propose that human groups shift to hierarchy to limit scalar stress, i.e. the increase in cost of organization as a group grows. Yet, this hypothesis lacks a mechanistic model to investigate the organizational advantage of hierarchy and its role on its evolution. To fill this gap, we describe social organization by the distribution of individuals’ capacity to influence others. We then integrate this formalization into models of social dynamics and evolutionary dynamics. First, our results demonstrate that hierarchy strongly reduces scalar stress, and that this benefit can emerge solely because leaders and followers differ in their capacity to influence others. Second, the model demonstrates that this benefit can be sufficient to drive the evolution of leader and follower behaviours and ultimately, the transition from small egalitarian to large hierarchical groups.


2019 ◽  
Vol 6 (5) ◽  
pp. 182160
Author(s):  
Beke Graw ◽  
Bart Kranstauber ◽  
Marta B. Manser

The majority of carnivore species are described as solitary, but little is known about their social organization and interactions with conspecifics. We investigated the spatial organization and social interactions as well as relatedness of slender mongooses ( Galerella sanguinea ) living in the southern Kalahari. This is a little studied small carnivore previously described as solitary with anecdotal evidence for male associations. In our study population, mongooses arranged in spatial groups consisting of one to three males and up to four females. Male ranges, based on sleeping sites, were large and overlapping, encompassing the smaller and more exclusive female ranges. Spatial groups could be distinguished by their behaviour, communal denning and home range. Within spatial groups animals communally denned in up to 33% of nights, mainly during winter months, presumably to gain thermoregulatory benefits. Associations of related males gained reproductive benefits likely through increased territorial and female defence. Our study supports slender mongooses to be better described as solitary foragers living in a complex system of spatial groups with amicable social interactions between specific individuals. We suggest that the recognition of underlying ‘hidden' complexities in these apparently ‘solitary' organizations needs to be accounted for when investigating group living and social behaviour.


2019 ◽  
Vol 18 ◽  
pp. e00618
Author(s):  
Aye Myat Thu ◽  
Guo-Gang Li ◽  
Mingxia Zhang ◽  
Tluang Hmung Thang ◽  
Aung Myat Soe ◽  
...  

2019 ◽  
Vol 11 (9) ◽  
pp. 14194-14203
Author(s):  
Deepak Rai ◽  
Jyoti

To understand the population growth dynamics and life history parameters of the Blackbuck, 24 fortnightly visits were made in and around Lalpur Jheel, Dobhi Village of district Hisar (Haryana) from March 2017 to February 2018.  Scan sampling method was used to record the Blackbuck population.  In the present study, a total of 68 sightings of Blackbuck were made including a minimum of one sighting per visit to a maximum of seven sightings per visit with group size varying from one individual to a maximum of 58 individuals per sighting.  The overall mean group size and crowding of the Blackbuck population were 13.84 ± 1.89 S.E. and 31.31 (N=941 individuals), respectively.  The population structure of Blackbuck revealed six different age and sex classes, namely, adult male, adult female, sub-adult male, sub-adult female, yearling male, and fawn.  As far as the social organization of the Blackbuck is concerned, six different types of social grouping were recorded, namely lone territorial male (adult male), unimale-unifemale (adult male and adult female), bachelor herd (adult male(s)/ sub-adult male(s)/ yearling male(s)), mixed herd (adult male(s)/ sub-adult male(s)/ yearling male(s)/ adult female(s)/ sub-adult female(s)/ fawn(s)), harem herd (1 adult male/ adult female(s)/ sub-adult female(s)/ fawn(s)), and female herd (adult female(s)/ sub-adult female(s)/ fawn(s)).  It was concluded that Blackbuck shows partial social organization as both the solitary and herd were observed during the present study.


1992 ◽  
Vol 52 (1) ◽  
pp. 17-20 ◽  
Author(s):  
F Thullier ◽  
D Desor ◽  
J Mos ◽  
B Krafft

The Auk ◽  
1984 ◽  
Vol 101 (4) ◽  
pp. 804-811 ◽  
Author(s):  
Richard A. Kiltie ◽  
John W. Fitzpatrick

Abstract A color-banded population of Black-capped Donacobius (Donacobius atricapillus) on a Peruvian oxbow lake was studied during one breeding season and censused for 3 yr thereafter. Eighteen territories along a marshy shoreline were occupied by groups of 2-4 donacobius. Each group contained a mated pair and 0-2 helpers, apparently offspring produced during 1-2 preceding breeding seasons. Helpers participated in nest surveillance, territorial displays, and feeding nestlings. Displays occurred at territory boundaries and consisted of loud duetting by the pair or group. Breeding coincided with the rainy months, October through April, and peaked in November-January. Clutch size was always two. Egg and nestling periods each lasted 17-18 days. No correlation was demonstrable between group size and overall fledging success. Trios, however, accounted for all cases in which both young successfully fledged, whereas pairs never fledged more than one young. Annual survivorship of breeding adults averaged 71%. Cooperative breeding in donacobius is associated with limited opportunities for acquiring breeding territories, as in many other cooperative breeders. The relatively short period during which young serve as helpers (and the resulting small family sizes), however, suggests that at other times or places breeding territories are more readily available to young.


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