Estimating age of immobilized elephants from teeth impressions using dental silicon

High precision condensation dental silicon, Zetalabor^TM, was used to create moulds of the lower jaw molars from 22 immobilized African elephants (Loxodonta africana Blumenback) during radio collaring operations. These moulds were used to determine the elephant's age using Laws and Jachmann's molar aging criteria. The technique proved easy and fast and produced useful imprints in 90% of the cases. We found our age estimates, based on physical appearance, made prior to immobilizations were relatively accurate, with 75% within ±3 years and 95% within ±5 years from the age indicated from molar evaluation. When re‐collaring the same individuals in 2–3 years, new moulds will be made to compare a known time period with the degree of tooth wear. This will provide verification of Laws age estimates from free‐ranging elephants.     

Considerations on the potential use of cliffs and caves by the extinct endemic late pleistocene hippopotami and elephants of Cyprus

Most of the fossil mammal sites on Cyprus, as well as on other Mediterranean islands, consist of large quantities of bones found in caves. Of 32 sites with Phanourios minutus and 21 with Elephas cypriotes on Cyprus, 19 were located in caves, two in rock-shelters, and 11 at open-air sites. Fifteen of them were littoral, four coastal, and 13 inland. The purpose of this paper is to examine possible reasons why Phanourios and Elephas remains accumulated mainly in littoral and coastal caves. Based on an analysis of the behavior exhibited by living hippopotami and elephants, we assume that the extinct large mammals of Cyprus entered these caves in search of fresh water and to protect themselves from the heat in the cool and moist cave environment. A further reason may have been that these mammals entered the caves seeking mineral licks to rectify possible mineral deficiencies, to bind secondary plant compounds such as tannins, or to counteract acidosis. By entering caves, or even passing along narrow paths through cliffs, they were at risk of becoming trapped in natural traps, such as caves with their openings facing upwards, sinkholes, and mire traps. There is no evidence that Phanourios and Elephas remains were accumulated by natural predators because on the island there were no predators large enough to carry such large mammals. The only exception are the remains in the Akrotiri Aetokremnos rock shelter on the Akrotiri peninsula, where there is evidence that the 218,459 Phanourios and 330 Elephas remains were accumulated by the first human settlers of Cyprus, about 10,000 years BP.     

The fast life of a dwarfed giant

In the first half of the 1960s, a rich paleontological site was discovered at Spinagallo caves (Eastern Sicily, Southern Italy). A very abundant fossil population (at least 104 specimens) of the dwarf elephant Elephas falconeri, the smallest elephant that ever lived, was recovered. We computed the survivorship curve for this fossil population in order to investigate both the great juvenile abundance and high calf mortality which it shows. Through the analysis of E. falconeri survivorship, of some reconstructed life-history traits, and of its ecology, and taking into account the Island rule (Foster, 1964), we concluded that E. falconeri moved somewhat toward the fast extreme of the slow-fast continuum in life-history traits in regards to its mainland ancestor E. antiquus, that is, it was somehow r-selected. In keeping with our findings, we propose a new explanation for the common occurrence of dwarfism in large mammals living on islands. We suggest the interplay of competition, resource allocation shift and feeding niche width could successfully explain this pattern.     

Phenotype matching and inbreeding avoidance in African elephants

Perhaps the most important 'decision' made by any animal (or plant) is whether to disperse--leave kith and kin, or remain with the familiar and related. The benefits of staying at home are obvious, so dispersal requires an explanation--and the most popular is that dispersal functions to avoid inbreeding depression. Strong support comes from the observation that dispersal is so often sex biased. Simply put, all else being equal members of both sexes should prefer to remain philopatric, but this would lead to inbreeding depression so members of one sex have to disperse. In principle, this link between inbreeding depression and sex-biased dispersal could be broken if individuals recognize close kin and avoid mating with them. Archie et al. (2007) provide one of the most compelling analyses to date of the interaction among inbreeding avoidance, kin recognition and mating strategies in any mammal, clearly showing that elephants recognize even close paternal kin and avoid mating with them. Their important results illuminate the subtleties of elephant inbreeding avoidance as well as illustrate the difficulty of arriving at definitive answers to questions about the evolution of dispersal behaviour.     

兴隆山自然保护区麝场圈养马麝刻板行为的比较

于2001年3月—2002年1月,采用焦点取样法对甘肃兴隆山自然保护区麝场圈养马麝的刻板行为进行了研究。结果表明:该麝场的圈养马麝有刻板行为的发育,雌麝的刻板行为持续时间少于雄麝,但二者间的差异不显著。野捕马麝幼年期的人工哺乳经历使其刻板行为表达强度相对小于麝场圈养下繁殖马麝。年龄对雌雄麝的刻板行为表达强度的效应相似,亚成体马麝的刻板行为表达较多,成体马麝体的刻板行为表达相对较少,老年马麝刻板行为持续时间最长,2.5和4.5岁是圈养马麝刻板行为发育的关键时期。此外,能顺利繁殖的个体,其刻板行为表达的持续时间少于繁殖失败的个体。     

Development of a Chinese-Indian hybrid (Chindian) rhesus macaque colony at the California National Primate Research Center by introgression

Background  Fullbred Chinese and Indian rhesus macaques represent genetically distinct populations. The California National Primate Research Center introduced Chinese founders into its Indian-derived rhesus colony in response to the 1978 Indian embargo on exportation of animals for research and the concern that loss of genetic variation in the closed colony would hamper research efforts. The resulting hybrid rhesus now number well over a thousand animals and represent a growing proportion of the animals in the colony.
Methods  We characterized the population genetic structure of the hybrid colony and compared it with that of their pure Indian and Chinese progenitors.
Results  The hybrid population contains higher genetic diversity and linkage disequilibrium than their full Indian progenitors and represents a resource with unique research applications.
Conclusions  The genetic diversity of the hybrids indicates that the strategy to introduce novel genes into the colony by hybridizing Chinese founders and their hybrid offspring with Indian-derived animals was successful.     

Plasma cholesterol levels in free-ranging macaques compared with captive macaques and humans

Plasma total cholesterol in free-ranging Japanese macaques (Macaca fuscata) on Koshima islet and in free-ranging long-tailed macaques (Macaca fascicularis) at Pangandaran in Indonesia was found to occur at very low levels compared with captive macaques and humans. Although total cholesterol levels in captive macaques were lower than humans, differences in HDL cholesterol levels were only small. In both sexes of wild and captive Japanese macaques, total cholesterol levels decreased from birth through to young adulthood but then increased in adult females of the captive group. In contrast, the value for adult females of the wild troop remained at a low level. Low TCH levels in adult females of the wild Japanese macaque troop may be due to a low energy intake and may have caused a delay in the onset of sexual maturation. Plasma TCH levels increased with the addition of 0.1% dietary cholesterol over six weeks in captive long-tailed macaques. That the cholesterol value after six weeks was dependent on cholesterol levels prior to supplementation indicates that captive macaques are slightly saturated with cholesterol.     

Elephants caught in the middle: impacts of war, fences and people on elephant distribution and abundance in the Caprivi Strip, Namibia

We conducted wet [26 March–4 April 2003 (Apr03)] and dry [1–8 November 2005 (Nov05)] season aerial surveys of African elephants ( Loxodonta africana Blumenbach) in the Caprivi Strip, Namibia to provide an updated status report on elephant numbers and distribution and assist with a historical analysis of elephant distribution and abundance in the Caprivi Strip. During the wet season when water was available in seasonal pans, elephants were widely distributed throughout the survey area. In contrast, during the dry season, a majority of elephant herds occurred within 30 km of the perennial Kwando, Linyanti and Okavango rivers and few herds occurred within the West Caprivi Game Reserve where water in the seasonal pans was limited. We estimated 5318 elephants for the 7731-km² survey area (0.71 elephants km⁻²) for the Apr03 wet season survey and 6474 elephants for the 8597-km² survey area (0.75 elephants km⁻²) for the Nov05 dry season survey. Based on our aerial surveys and reports of elephant numbers and distribution from historical aerial surveys and telemetry studies, civil war, veterinary fences and human activities appear to have effected changes in African elephant abundance, distribution and movements in the Caprivi Strip, Namibia since 1988 when the first comprehensive aerial surveys were conducted.     

Mirror mediated object discrimination and self-directed behavior in a female gorilla

Mirror mediated object discrimination was investigated in a captive female, human-reared, western lowland gorilla (Gorilla gorilla gorilla) approximately 26 years of age. The gorilla was trained to find a stimulus that was only visible by use of the mirror. The gorilla could not reach the goal object except by observing it in the mirror and her hand movement was not visible through the mirror. Further, it was hypothesized that this mirror mediated object discrimination would enhance the probability of self-directed behavior.Gallup’s (1970) marking paradigm, excluding the use of general anesthesia, was utilized in assessing self-directed behavior. Mirror-gazing, face-directed, and mark-directed behavior with a mirror were compared before versus after discrimination mirror training. The results supported the hypotheses that gorillas are capable of mirror mediated object discrimination and that mirror training involving a discrimination task would facilitate self-directed behavior.