Group Size in Elephants of Tsavo National Park and Possible Factors Influencing it

10.2307/3883 ◽  
1976 ◽  
Vol 45 (2) ◽  
pp. 425 ◽  
Author(s):  
Walter Leuthold
Parasitology ◽  
2018 ◽  
Vol 146 (5) ◽  
pp. 670-677
Author(s):  
Fernando Aguilar Montiel ◽  
Arturo Estrada-Torres ◽  
Roxana Acosta ◽  
Miguel Rubio-Godoy ◽  
Jorge Vázquez

AbstractStudies of abundance and distribution of organisms are fundamental to ecology. The identity of host species is known to be one of the major factors influencing ectoparasitic flea abundance, but explanations are still needed regarding how host taxa influence abundance parameters of different flea species. This study was carried out at La Malinche National Park (LMNP), Tlaxcala, Mexico, where previously 11 flea species had been recorded on 8 host species. Our aims were to list micromammal flea species, to determine flea infection parameters [flea prevalence (FP) and flea mean abundance (FMA)] and to analyse the influence of host species on these parameters. A total of 16 species of fleas were identified from 1178 fleas collected from 14 species of 1274 micromammals captured with Sherman®traps from March 2014 to December 2015 in 18 sites at LMNP. Some host species influence FP and FMA, in particular,Microtus mexicanusandPeromyscus melanotisshowed particularly higher infection values than other host species.Plusaetis aztecusandPlusaetis sibynuswere identified as the most abundant flea species.


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.


Behaviour ◽  
2014 ◽  
Vol 151 (7) ◽  
pp. 1045-1066 ◽  
Author(s):  
Julie A. Teichroeb ◽  
Eva C. Wikberg ◽  
Nelson Ting ◽  
Pascale Sicotte

Male Colobus vellerosus compete intensely for access to females, which sometimes leads to mortal wounding. Yet, males often form cooperative relationships to overtake prime-aged males and immigrate into bisexual groups. We investigated the factors that predicted the presence of coalitions and affiliative relationships among males in this species. Interactions among males in 292 dyads from six groups were examined from 2004 to 2010 at Boabeng-Fiema, Ghana. Affiliation rates among males were higher and aggression rates lower when one or both males in the dyad were subadult, compared to adult male dyads. Affiliation rates tended to be higher among males that were kin but no other aspect of male relationships predicted affiliation. Coalitions among males were rarely observed and primarily occurred in the context of joint defense against extra-group males (93.5% of events). Adult males were more likely to provide coalitionary support than subadults and coalitions occurred significantly more often when both males were high ranking, since these males probably benefited most in terms of reproductive success from excluding extra-group males. Rank-changing and leveling coalitions among low-ranking males appear to be quite rare or absent in C. vellerosus. The costs of these types of coalitions may be too high or male group size too small on average for these types of coalitions to have been selected for. The overall low rates of affiliation and coalitions among male C. vellerosus are likely influenced by male-biased dispersal and the high level of male–male competition.


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