scholarly journals Social organization in a North African ground squirrel

2020 ◽  
Vol 101 (3) ◽  
pp. 670-683 ◽  
Author(s):  
Annemarie van der Marel ◽  
Jane M Waterman ◽  
Marta López-Darias
Keyword(s):  
Social Organization ◽  
Ground Squirrel ◽  
Genetic Relatedness ◽  
Size Composition ◽  
Ground Squirrels ◽  
Adult Males ◽  
Active Season ◽  
Trade Offs ◽  
The Social ◽  
Cape Ground Squirrel

Abstract Research on sociality in temperate ground-dwelling squirrels has focused on female philopatry and other life history trade-offs, which are influenced by constraints in the duration of the active growing season. Temperate ground-dwelling squirrels that experience high predation pressure, are large in body size, and have a short active season, show a more complex social organization. In contrast, African ground squirrels are active year-round, suggesting that instead of a short active season, distinct selective pressures influence their social organization. We examined the social organization of Barbary ground squirrels, Atlantoxerus getulus, and compared the social organization of temperate and African ground-dwelling sciurids. Anecdotal accounts on Barbary ground squirrels’ social organization suggested that they were either solitary or gregarious, or live in small family groups. We recorded the group size, composition, cohesion, and genetic relatedness, of the population on the arid island of Fuerteventura, Spain. Our data indicate that females live in small (1–8) all-female kin groups separate from adult males, and that unrelated adult males share sleeping burrows with immature individuals of either sex. We observed sex-biased dispersal with males primarily the dispersing sex and females primarily philopatric. Females sleep solitarily during gestation and lactation and nest either communally or singly after juvenile emergence. During the day, males and females can be active in the same area. Barbary ground squirrels are social because the squirrels share sleeping burrows and show spatiotemporal overlap. Barbary ground squirrels’ social organization resembles that of the closely related Cape ground squirrel rather than that of the temperate ground-dwelling sciurids, although the former are more temperate, seasonal breeders. In addition to describing the social organization of a previously unstudied species, this paper sheds light on the ecological drivers of sociality, and the evolution of distinct social organizations in ground-dwelling sciurids.

scholarly journals Mortality in relation to season, age, sex, and reproduction in Columbian ground squirrels (Spermophilus columbianus)

2001 ◽  
Vol 79 (3) ◽  
pp. 465-470 ◽  
Author(s):  
P Neuhaus ◽  
N Pelletier
Keyword(s):  
Ground Squirrels ◽  
Reproductive Status ◽  
Adult Males ◽  
Active Season ◽  
Life History Data ◽  
Spermophilus Columbianus ◽  
Trade Offs ◽  
Maternal Survival ◽  
Mortality Increase ◽  
Columbian Ground Squirrels

We investigated the timing of and age at mortality in Columbian ground squirrels (Spermophilus columbianus) in relation to sex and reproductive status. Life-history data were collected from 1994 to 1999 in the foothills of the Rocky Mountains, Alberta, Canada. We predicted increased mortality for males during mating and for females during lactation. Further, we expected reproductively successful females to have higher mortality than females that did not reproduce successfully. Finally we assumed that at some age reproductive success of females would decrease and mortality increase because of old age. For both sexes, survival over winter was high (ca. 90%) for adults. While there was a significant increase in mortality of adult males during the mating season, females did not have higher mortality during lactation than during the rest of the active season. Reproductive status influenced mortality in females: non-reproducing females had a higher chance of surviving than reproducing females. Females that weaned young were more likely to die after the weaning period than females that lost their litter during lactation. There was a positive correlation between maternal survival and survival of offspring to yearling age. Our results showed evidence of trade-offs between reproduction and survival of male and female Columbian ground squirrels.

scholarly journals Age of maturation and behavioral tactics in male yellow ground squirrel Spermophilus fulvus during mating season

2014 ◽  
Vol 60 (6) ◽  
pp. 700-711 ◽  
Author(s):  
Nina A. Vasilieva ◽  
Ekaterina V. Pavlova ◽  
Sergey V. Naidenko ◽  
Andrey V. Tchabovsky
Keyword(s):  
Body Size ◽  
Ground Squirrel ◽  
Life History Theory ◽  
Social Activity ◽  
Indirect Evidence ◽  
Adult Size ◽  
Adult Males ◽  
Mating Season ◽  
Active Season ◽  
Good Physical Condition

Abstract Life-history theory predicts that in hibernators age of maturation is related positively to body size and negatively to the duration of active season aboveground. Yellow souslik is a large-sized ground squirrel with long hibernation, which suggests late maturation. We used four-year field observations of marked individuals to determine the age of maturation in males through analysis of age-dependent variation in body size, mass, androgen status, timing of spring emergence, ranging patterns and social behavior during the mating season. Yearling males were smaller, lighter, had lower level of fecal testosterone, emerged later and had smaller home ranges than older males. Social activity and the number of females encountered did not differ between age classes. After the second hibernation none of the studied parameters varied with age. Cluster analysis revealed two behavioral tactics: “active” males (adults only) emerged earlier, ranged more widely, initiated more contacts, encountered more females and were heavier than “passive” males (both yearling and adult). Thus, males of S. fulvus reached adult size and matured after two hibernations, which is relatively fast for such a big species with short active period. Indirect evidence for copulations and high variation among yearlings in all parameters suggest that some of them might successfully compete with adults. Active tactic of wandering and searching for females is energetically costly, and probably only adult males in good physical condition can afford it, whereas passive tactic of residing is energy saving and good for adults in poor condition and for yearlings that are continuing to grow.

To breed or not to breed: an analysis of the social and density-dependent constraints on the fecundity of female badgers ( Meles meles )

1992 ◽  
Vol 338 (1286) ◽  
pp. 393-407 ◽  
Keyword(s):  
Social Organization ◽  
Post Partum ◽  
Seasonal Pattern ◽  
Reproductive Failure ◽  
Late Winter ◽  
Breeding Cycle ◽  
Adult Males ◽  
Potential Productivity ◽  
The Social ◽  
Two Peaks

Data from post-mortem examinations, population density estimates and long term capture-mark-recapture studies have been combined to look at the pattern of reproductive behaviour and the social factors leading to reproductive failure in badgers in Britain. The results are used to evaluate whether the hypothesis that the defence of oestrous females (as opposed to defence of food resources) best explains territorial behaviour and the social organization of badgers. Badgers in Britain have two peaks of reproductive activity, one immediately post partum and one in the summer/autumn. These coincide with two peaks of ovulation, and in the late winter/spring there is a steep rise in the number of sows carrying blastocysts, to reach an asymptote in June for yearling sows and April in older sows. Measured by their contribution to overall productivity, winter/spring matings were much more important than summer/autumn matings, contributing 65% of total autumn blastocysts in yearling sows and 71% of autumn blastocysts in older sows. The relative importance of the two mating periods is reflected in the seasonal pattern of bite wounding in adult male badgers; minor bite wounding in January-March was 2.3 times as frequent as in August-October, and moderate-extensive bite wounding was 3.1 times more frequent. In the populations studied, pre- and post-natal losses were high, with reproductive failure occurring at all stages of the breeding cycle, so that less than 30% of potential productivity was achieved. Indeed 22% of sows failed to develop blastocysts; these had a lower body mass, less body fat, larger adrenal glands, poorer health and higher bite wound scores than sows with blastocysts. Only 44% of adult sows implanted their blastocysts and proceeded to the end of pregnancy. However, it was less easy to identify features characteristic of sows that did or did not go on to implant their blastocysts. Finally, 35% of sows that produced cubs ceased lactation early, and this loss of entire litters was thought to be due to infanticide by dominant sows. The presence of annexe setts correlates with increased productivity in younger sows, and this is thought to be because annexe setts enable younger sows and their cubs to avoid the aggression of older, more dominant sows. Living in large social groups has no net reproductive gain for adult males or females, and there was a decline in productivity (per adult) with increasing group size. Although paternity measures were not available to assess the individual gains from group living, the absence of mate guarding and the frequency of cuckoldry and of mixed-paternity litters suggests that mating is not the sole, or probably even the major, prerogative of a dominant boar. The data so far question the hypothesis that the social organization of badgers evolved to monopolize access to oestrous females.

Growth and its relationship to the initial annual cycle of the golden-mantled ground squirrel, Spermophilus lateralis

1981 ◽  
Vol 59 (6) ◽  
pp. 865-871 ◽  
Author(s):  
John A. Phillips
Keyword(s):  
Litter Size ◽  
Annual Cycle ◽  
Ground Squirrel ◽  
Growth And Development ◽  
Reproductive Effort ◽  
Ground Squirrels ◽  
Active Season ◽  
Spermophilus Lateralis ◽  
Significant Difference ◽  
Two Populations

Thirty-eight litters of golden-mantled ground squirrels (Spermophilus lateralis), from two populations that experienced different lengths of active season, were born and raised in the laboratory. Growth and development in young were inversely related to litter size. Offspring from smaller litters were both able to attain their prehibernation peak of body mass sooner and hibernate after fewer days of homeothermy than squirrels from larger litters. Young that remained homeothermic throughout the initial overwintering period were always from large litters and among the slowest growing littermates. Fecundity was lower in females from the temporally compressed environment. There was no significant difference between populations in the nutrition provided by mothers to their litters. The results suggest that reproductive effort is more conservative in populations of ground squirrels that experience short seasons of activity, yet this conservatism allows the offspring of those populations to reach independence and attain the prehibernation state of preparedness at an earlier age than their counterparts from populations of more moderate climates.

Spatial relationships and social organization of adult Richardson's ground squirrels

1979 ◽  
Vol 57 (1) ◽  
pp. 125-139 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Nearest Neighbor ◽  
Average Distance ◽  
Ground Squirrels ◽  
Core Area ◽  
Adult Males ◽  
Active Season ◽  
The Core ◽  
Uniform Dispersion ◽  
Usual Concept ◽  
Core Areas

The spacing patterns among a group of adult Spermophilus richardsonii were studied in 1975 and 1976. Major features of the social structure were as follows: relatively uniform dispersion of the Squirrels, overlap of ranges with overlap reaching a maximum after weaning of young and before hibernation, and dominance within the core area (defined as the area in which a squirrel concentrated 50% of its aboveground time). Although there was greater proximity among kin than among nonkin, each adult maintained a separate core area. Adult males played no role in assisting females to rear young, and males were dominant to females only when within their own core areas. Throughout the active season the size of the core area remained relatively constant at about 225 m2 and the average distance between a squirrel and its nearest neighbor remained at about 20–25 m. The core area differed from the usual concept of a territory in that it was characterized by reduced submission rather than increased aggression by the resident toward intruders.

scholarly journals A multi-level society comprised of one-male and multi-male core units in an African colobine (Colobus angolensis ruwenzorii)

2019 ◽  
Author(s):  
Samantha M. Stead ◽  
Julie A. Teichroeb
Keyword(s):  
Social Organization ◽  
Mammalian Species ◽  
Hierarchical Cluster ◽  
Adult Males ◽  
Hamadryas Baboons ◽  
The Social ◽  
Multi Level ◽  
Using Data ◽  
Hierarchical Cluster Analyses ◽  
Insight Into

AbstractA few mammalian species exhibit complex, nested social organizations, termed multi-level societies. Among nonhuman primates, multi-level societies have been confirmed in several African papionin and Asian colobine species. Using data on individually-recognized Rwenzori Angolan colobus at Lake Nabugabo, Uganda, we document the first multi-level society in an African colobine. The study band comprised up to 135 individuals living in 12 socially and spatially distinct core units that ranged in size from 4 to 23 individuals. These core units shared a home range, and fissioned and fused throughout the day. Using the association indices between core units, we employed hierarchical cluster analyses and permutation tests to show that some core units clustered into clans. Thus, we confirm three tiers of social organization for Rwenzori Angolan colobus: core unit, clan, and band. The social organization of this subspecies is unlike any reported previously in a nonhuman primate, with about half the core units containing a single adult male and the others containing multiple reproductive adult males. Preliminary data show males to transfer within the band and female to transfer outside of the band, which suggests that, like Hamadryas baboons, this subspecies could provide insight into the selective pressures underlying hominin social organization.

scholarly journals Determination of an optimal dose of medetomidine-ketamine-buprenorphine for anaesthesia in the Cape ground squirrel (Xerus inauris)

2011 ◽  
Vol 82 (2) ◽  
Author(s):  
K. E. Joubert ◽  
T. Serfontein ◽  
M. Scantlebury ◽  
M B Manjerovic ◽  
P. W. Bateman ◽  
...  
Keyword(s):  
Ground Squirrel ◽  
Abdominal Cavity ◽  
Optimal Dose ◽  
Ground Squirrels ◽  
Temperature Logger ◽  
Xerus Inauris ◽  
Cape Ground Squirrel ◽  
The Mean ◽  
Surgical Implantation

The optimal dose of medetomidine-ketamine-buprenorphine was determined in 25 Cape ground squirrels (Xerus inauris) undergoing surgical implantation of a temperature logger into the abdominal cavity. At the end of anaesthesia, the squirrels were given atipamezole intramuscularly to reverse the effects of medetomidine. The mean dose of medetomidine was 67.6±9.2 μg/kg, ketamine 13.6±1.9 mg/kg and buprenorphine 0.5±0.06 μg/kg. Induction time was 3.1 ± 1.4 min. This produced surgical anaesthesia for 21± 4.2 min. Atipamezole 232±92 μg/kg produced a rapid recovery. Squirrels were sternally recumbent in 3.5 ± 2.2 min.

Seasonal changes in body composition of the arctic ground squirrel, Citellus undulatus

1976 ◽  
Vol 54 (1) ◽  
pp. 74-78 ◽  
Author(s):  
William Galster ◽  
Peter Morrison
Keyword(s):  
Seasonal Changes ◽  
Ground Squirrel ◽  
Significant Loss ◽  
Ground Squirrels ◽  
The Arctic ◽  
Average Weight ◽  
Active Season ◽  
Loss Of Weight ◽  
Glucose Synthesis ◽  
Arctic Ground Squirrels

The depletion or accumulation of body reserves is followed in terms of the weight and proportion of lipid, protein, water, and minerals in arctic ground squirrels during the entry, deep, and emergent phases of the hibernation season and after the reproductive phase of the active season. Average weight increased slowly through the summer, from a minimum of 346 g, until mid-August when 190 g accumulated in 3 weeks to be used subsequently during the 220-day hibernation season beginning in mid-September. During hibernation, the 325-g loss in weight represents 62% lipid, 26% water, 9% protein, and 2% mineral. Fat in lipid provides most of the energy but insufficient amounts of carbon for glucose synthesis during hibernation. However, protein provides an adequate gluconeogenic reserve. Significant loss of mineral indicates that skeletal reserves of calcium are important during hibernation. After hibernation, continued loss of weight by females indicates further utilization of reserves during gestation and nursing.

Food and space: resources defended by territorial parous female Columbian ground squirrels

1994 ◽  
Vol 72 (11) ◽  
pp. 1908-1914 ◽  
Author(s):  
David A. Boag ◽  
Darwin R. Wiggett
Keyword(s):  
Body Mass ◽  
Significant Role ◽  
Ground Squirrel ◽  
Ground Squirrels ◽  
Differential Treatment ◽  
Adult Males ◽  
Spermophilus Columbianus ◽  
Columbian Ground Squirrels ◽  
Experimental Plots

The importance of food and space, as resources defended by parous female Columbian ground squirrels (Spermophilus columbianus), was studied by manipulating one of these resources, that is increasing the quality of forage (through urine fertilization) on small plots within territories. Use of these fertilized plots by ground squirrels increased more than 100-fold when averaged over 2 years after manipulation. This increase, however, was not equal for each sex and age class: parous females used the fertilized plots relatively more, and nonparous females less, than either yearling or adult males. The number of parous females with territories overlapping the experimental plots also increased after fertilization, but the size of their territories declined only slightly, by less than 10%. Parous females with access to the fertilized plots, relative to those without such access, had greater body mass and larger litters that both weighed more at birth and gained body mass subsequently more rapidly. Parous females on territories with fertilized plots showed higher levels of agonism than those on territories lacking such plots. Most of the agonism was centered on the experimental plots and more of it was directed at young of other females than at their own young. Such differential treatment of kin, however, did not extend to their offspring of the previous year. We suggest that for parous females of this ground squirrel, both food and space (at least that normally needed to supply sufficient forage) are important resources to defend, and both may have played a significant role in the evolution of territoriality in females of this species.

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