Elephant Group Research Articles

Results of vaccination of Asian elephants (Elephas maximus) with monovalent inactivated rabies vaccine

To evaluate the humoral immune response of Asian elephants to a primary IM vaccination with either 1 or 2 doses of a commercially available inactivated rabies virus vaccine and evaluate the anamnestic response to a 1-dose booster vaccination. 16 captive Asian elephants. Elephants with no known prior rabies vaccinations were assigned into 2 treatment groups of 8 elephants; 1 group received 1 dose of vaccine, and the other group received 2 doses of vaccine 9 days apart. All elephants received one or two 4-mL IM injections of a monovalent inactivated rabies virus vaccine. Blood was collected prior to vaccination (day 0) and on days 9, 35, 112, and 344. All elephants received 1 booster dose of vaccine on day 344, and a final blood sample was taken 40 days later (day 384). Serum was tested for rabies virus-neutralizing antibodies by use of the rapid fluorescent focus inhibition test. All elephants were seronegative prior to vaccination. There were significant differences in the rabies geometric mean titers between the 2 elephant groups at days 35, 112, and 202. Both groups had a strong anamnestic response 40 days after the booster given at day 344. Results confirmed the ability of Asian elephants to develop a humoral immune response after vaccination with a commercially available monovalent inactivated rabies virus vaccine and the feasibility of instituting a rabies virus vaccination program for elephants that are in frequent contact with humans. A 2-dose series of rabies virus vaccine should provide an adequate antibody response in elephants, and annual boosters should maintain the antibody response in this species.

A review of injuries caused by elephants in captivity: an examination of predominant factors

Injuries to people caused by elephants in zoos can be lethal. Data on incidents of injury to keepers and visitors were collated from newspaper articles, personal communications with zoo directors and keepers, and published information from the European Elephant Group. Although the data were not of consistent quality and detail across the three sources, the causes and frequency of incidents were analysed to see whether analogies could be drawn about how and why accidents occur. The greater our understanding of these factors, the more likely it is that the number of elephant‐related injuries and deaths that happen in zoos can be reduced. Data are presented on a number of factors that relate to elephants, keeping staff, management practices and the circumstances surrounding known injuries and deaths.

African elephant home range and habitat selection in Pongola Game Reserve, South Africa

The ranging behaviour and habitat occupancy by three elephant groups (cow herd, bulls, and an orphan group) were studied over a two-year period in a small, fenced reserve. No summer dispersal was observed. Distinct seasonal home ranges were exhibited for all groups, with the summer (wet season) ranges being smaller than the winter (dry season) ranges. Home range size was much smaller than in other locations. The dam and surrounding high density of patches of vegetation of high nutritional quality are thought to be the reasons. Habitat selection was strongly evident with all of the elephant groups selecting River Line habitats in the dry season. In the wet season the cow herd and orphans selected the more open Acacia habitats and the bulls exhibited no significant habitat preference.

African elephant home range and habitat selection in Pongola Game Reserve, South Africa

The ranging behaviour and habitat occupancy by three elephant groups (cow herd, bulls, and an orphan group) were studied over a two-year period in a small, fenced reserve. No summer dispersal was observed. Distinct seasonal home ranges were exhibited for all groups, with the summer (wet season) ranges being smaller than the winter (dry season) ranges. Home range size was much smaller than in other locations. The dam and surrounding high density of patches of vegetation of high nutritional quality are thought to be the reasons. Habitat selection was strongly evident with all of the elephant groups selecting River Line habitats in the dry season. In the wet season the cow herd and orphans selected the more open Acacia habitats and the bulls exhibited no significant habitat preference.

Nocturnal behavior in a group of female African elephants

AbstractThe nocturnal behavior of a stable group of female, African elephants (Loxodonta africana africana) was studied to: (1) examine their behavior as a function of hour of night; (2) qualitatively compare the elephants' activity budgets to those reported in a previous study; and (3) document the presence of aggressive and stereotypic behaviors that might necessitate a change in their management. The elephants were systematically observed at least five times per week for 10 weeks between 17:00 and 08:00. Instantaneous focal samples of behavior, location, and proximity were taken every minute on a rotating basis, and all observed occurrences of social behavior were recorded. The hour of night affected elephant activity: significant relationships were found between hour of night and percent of time they spent feeding, lying, and standing. The overall activity budgets of the elephants were similar to the activity budgets reported in a previous study, although differences were evident in lying, stereotypic, and social behaviors. These differences might be a function of age. Affiliative behaviors accounted for 57% of the elephants' social behaviors, and agonistic behaviors among the elephants occurred infrequently and caused no injuries. Additionally, the elephants used all areas to which they had access. These findings provide compelling evidence that unrestricted social access during the night is the appropriate management strategy for these elephants. The results from the present study also highlight the importance of replicating existing studies and using multiple behavioral measures to make decisions regarding the welfare and management of stable groups of captive elephants. Zoo Biol 25:173–186, 2006. © 2006 Wiley‐Liss, Inc.

Dominance rank relationships among wild female African elephants, Loxodonta africana

Socioecological models of the evolution of female-bonded societies predict a relation between resource distribution and the nature of female affiliative and dominance relationships. Species that mainly rely on abundant, widely distributed resources, like African savanna elephants, are predicted to have unresolved dominance hierarchies and poorly differentiated female social relationships. Contrary to this prediction, female elephants have well-differentiated social relationships; however, little is known about the nature of their dominance rank relationships. Here we present the first quantitative analysis of dominance relationships within ‘family’ groups of adult female elephants in two wild populations: one in Amboseli National Park, Kenya, and another in Tarangire National Park, Tanzania. We tested three possibilities, that female elephants: (1) are egalitarian, (2) have linear, nepotistic hierarchies, or (3) have linear age/size-ordered hierarchies. Our results best support the third outcome: dominance rank relationships were transitive within families and highly asymmetrical within dyads, such that older, larger females consistently dominated smaller, younger females. We discuss the implications of this result for understanding the evolution of female social relationships.

The Sevsk woolly mammoth ( Mammuthus primigenius) site in Russia: Taphonomic, biological and behavioral interpretations

Excavations at Sevsk, Bryansk Region, Russia, by the Paleontological Institute of the Russian Academy of Sciences in 1988–1991 recovered 3800 bones of woolly mammoth ( Mammuthus primigenius Blum.) representing a minimum of 33 individuals. The locality is one of the largest naturally occurring deposits of mammoth remains in Europe and is inferred to be a catastrophic death assemblage. The material includes five skeletons of juvenile mammoths, from 1 month to 6 or 7 years of age, as well as partial skeletons and isolated bones of adult individuals. A femur and humerus of an approximately 10–12-month-old fetus are also among the finds. Morphological features suggest that the Sevsk mammoths belonged to one family group; the age structure and sexual composition of the assemblage do not differ significantly from that of a family group of Modern African elephants. In contrast to other localities in Siberia and central Russia, relatively more (about 45% of individuals) prepubertal animals are preserved at Sevsk. Radiocarbon dates indicate that the mammoths died about 14,000 years ago. Data from diatoms, pollen and rodents, as well as archeological evidence, corroborate this age, and provide the basis for a paleoenvironmental reconstruction at the end of the Valdaian Glaciation in western Russia.

CLASSIFICATION OF AFRICAN ELEPHANT LOXODONTA AFRICANA RUMBLES USING ACOUSTIC PARAMETERS AND CLUSTER ANALYSIS

ABSTRACT It has been suggested that African savanna elephants Loxodonta africana produce 31 different call types (Langbauer 2000). Various researchers have described these calls by associating them with specific behavioural contexts. More recently Leong et al. (2003) have attempted to classify elephant call types based on their physical properties. They classified 8 acoustically distinct call types from a population of captive elephants. This study focuses on one of these call types, the rumble, in a wild population of elephants in Kruger National Park, South Africa. A single family group of elephants was followed to record group behaviours and vocalizations from January through August 2001. By measuring the physical properties of 663 rumbles and subjecting these to cluster analysis, we present evidence that shows that rumbles can be categorized by their physical properties and that the resulting rumble types are associated with specific group behaviours. We characterize three types of rumbles that differ significantly by ten acoustic parameters. Two rumble types were associated with the elephant group feeding and resting, while the third was associated with socializing and agitation.

Survey of the reproductive cyclicity status of Asian and African elephants in North America

AbstractThe Asian and African elephant populations in North America are not self‐sustaining, and reproductive rates remain low. One problem identified from routine progestagen analyses is that some elephant females do not exhibit normal ovarian cycles. To better understand the extent of this problem, the Elephant TAG/SSP conducted a survey to determine the reproductive status of the captive population based on hormone and ultrasound evaluations. The survey response rates for facilities with Asian and African elephants were 81% and 71%, respectively, for the studbook populations, and nearly 100% for the SSP facilities. Of the elephants surveyed, 49% of Asian and 62% of African elephant females were being monitored for ovarian cyclicity via serum or urinary progestagen analyses on a weekly basis. Of these, 14% of Asian and 29% of African elephants either were not cycling at all or exhibited irregular cycles. For both species, ovarian inactivity was more prevalent in the older age categories (>30 years); however, acyclicity was found in all age groups of African elephants. Fewer elephant females (∼30%) had been examined by transrectal ultrasound to assess reproductive‐tract integrity, and corresponding hormonal data were available for about three‐quarters of these females. Within this subset, most (∼75%) cycling females had normal reproductive‐tract morphologies, whereas at least 70% of noncycling females exhibited some type of ovarian or uterine pathology. In summary, the survey results suggest that ovarian inactivity is a significant reproductive problem for elephants held in zoos, especially African elephants. To increase the fecundity of captive elephants, females should be bred at a young age, before reproductive pathologies occur. However, a significant number of older Asian elephants are still not being reproductively monitored. More significantly, many prime reproductive‐age (10–30 years) African females are not being monitored. This lack of information makes it difficult to determine what factors affect the reproductive health of elephants, and to develop mitigating treatments to reinitiate reproductive cyclicity. Zoo Biol 23:309–321, 2004. © 2004 Wiley‐Liss, Inc.

Physiological and haematological fundings in immobilized free-ranging African elephants

Reviews results found during the monitoring of physiology and haematology attributes of 56 elephant (26 adults, 14 subadults and 16 juveniles) captured in Ol Pejeta Ranch in Laikipia and transferred about 250 kms to Meru NP in July 2002. 9 bulls and 7 family groups were involved, and 51 of the 56 animals survived the transfer. The elephant were anaesthesized with a mixture of etorphine HCI (M99) and hyaluronidase. Drug monitoring records were assessed according to three age groups adults, subadults, and juveniles. Darting of the adults and subadults was done from a helicopter while the calves were darted from ground level. 'Results of this study show that most physiologic parameters are different in the 3 age groups of elephants. Respiratory rate and pulse rate was significantly different between adults and juvenile and between juveniles and subadults with the juveniles having the highest and the adults the lowest as is also the case in body temperature. 'This is attributed to the high metabolic rate in young animals'. Mean corpuscular value and haemoglobin were highest in adults and lowest in juveniles while white blood cells count was significantly higher in juveniles than in adults. 'The range for haematological parameters compared well with those reported by other authors except for the white blood cell counts', but actual data is difficult to compare because other authors rarely recorded the age groups separately.

Predicting spatial aspects of human–elephant conflict

Summary Human–elephant conflict (HEC) in Africa occurs wherever these two species coincide, and poses serious challenges to wildlife managers, local communities and elephants alike. Mitigation requires a detailed understanding of underlying patterns and processes. Although temporal patterns of HEC are relatively predictable, spatial variation has shown few universal trends, making it difficult to predict where conflict will take place. While this may be due to unpredictability in male elephant foraging behaviour (the male behaviour hypothesis) it may also be due to variations in the data resolution of earlier studies. This study tested the male behaviour and data resolution hypotheses using HEC data from a 1000‐km2 unprotected elephant range adjacent to the Masai Mara National Reserve in Kenya. HEC incidents were divided into crop raiding and human deaths or injuries. Crop raiding was further subdivided into incidents involving only male elephants or family groups. A relatively fine‐resolution, systematic, grid‐based method was used to assign the locations of conflict incidents, and spatial relations with underlying variables were explored using correlation analysis and logistic regression. Crop raiding was clustered into distinct conflict zones. Both occurrence and intensity could be predicted on the basis of the area under cultivation and, for male elephant groups, proximity to major settlements. Conversely, incidents of elephant‐induced human injury and death were less predictable but were correlated with proximity to roads. A grid‐based geographical information system (GIS) with a 25‐km2 resolution utilizing cost‐effective data sources, combined with simple statistical tools, was capable of identifying spatial predictors of HEC. At finer resolutions spatial autocorrelation compromised the analyses. Synthesis and applications. These results suggest that spatial correlates of HEC can be identified, regardless of the sex of the elephants involved. Moreover, the method described here is fully transferable to other sites for comparative analysis of HEC. Using these results to map vulnerability will enable the development and deployment of appropriate conflict mitigation strategies, such as guarding, early warning systems, barriers and deterrents. The utility of such methods and their strategic deployment should be assessed alongside alternative land‐use and livelihood strategies that limit cultivation within the elephant range.

Status of the so-called African pygmy elephant ( Loxodonta pumilio ( Noack 1906)): phylogeny of cytochrome b and mitochondrial control region sequences

Among the African elephants, it has been unanimously acknowledged that the forest elephants ( cyclotis form) are peculiar, so that they have been elevated to the specific rank. The development of molecular analyses of extant Loxodonta has only focused on two forms yet: the savannah form ( africana) and the forest form ( cyclotis), disregarding the so-called pygmy elephants ( pumilio or fransseni) the systematic status of which has been debated since their discovery. Therefore, we have sampled nine dwarfed-labelled specimens in collection and eight specimens of typical forest elephants that we compared to three savannah elephants and two Asian elephants. Because of the degraded nature of the nuclear DNA content in bone samples of old specimens, we assayed mitochondrial markers; 1961 bp of the mitochondrial genome were sequenced (over a continuous range spanning the cytochrome b gene, tRNA Thr, tRNA Pro, hypervariable region 1 and central conserved region of the control region). Pumilio and cyclotis are not sister-taxa: the phylogenetic analyses rather account for the inclusion of the so-called pygmy elephants within a monophyletic group of forest elephants sensu lato. The internal structure of this clade reveals to depend on isolation and remoteness between populations, characteristics that may have been extensively influenced by climatic variations during the Quaternary period. We conclude that the specific taxon Loxodonta pumilio (or Loxodonta fransseni) should be abandoned. To cite this article: R. Debruyne et al., C. R. Biologies 326 (2003).

Medetomidine a novel immobilizing agent for the elephant ( Elephas maximus)

Medetomidine was injected by the intramuscular route at the rates of 3 and 5 μg/kg body weight into two groups of Indian elephants ( Elephas maximus). Sedation was induced at 6.20 (0.81) and 5.90 (0.60) min respectively after injection. The duration of anaesthesia was 66.20 (10.4) and 134.20 (24.12) min, respectively and recovery occurred at 125.80 (25.23) and 205.89 (29.3) min. The notable signs of sedation exhibited by the elephants were protrusion of penis, complete relaxation of trunk, flaccidity of tail and drooping of the ears with a head down position. During sedation, physiological parameters recorded were bradycardia, decreased respiration and hypothermia.

Sexual segregation in habitat use by elephants in Chobe National Park, Botswana

AbstractWe report on a study conducted on free‐ranging African elephants in the woodlands of northern Botswana. We compared bull groups and family units with regard to (1) their patterns of habitat use and (2) their ranging distances from perennial water sources. During the dry season, adult males frequented more habitat types than family units, whereas family units used a wider diversity of habitats than bulls during the wet season. Bulls roamed widely (>10 km) from perennial drinking water in the dry season, when family units congregated within 3.5 km of the rivers. During the wet season, when ephemeral pans were abundant, all elephant groups were found at intermediate distances (5 km) from the rivers. The spacing of elephants in the dry season is consistent with sexual segregation but we reject the hypothesis that this is an outcome of indirect competition for food, because our concurrent studies on elephant feeding ecology found no evidence for intraspecific competition. Instead, we propose that most adult male elephants space themselves to avoid conflict with musth bulls and roam widely in the dry season between discretely distributed feeding ‘hotspots’. The small proportion of males that are in musth remain close to family units to maximize mating opportunities, and family units are unable to range far from water in the dry season. This is due to (1) comparatively high rates of water turn‐over among juveniles and lactating cows and (2) the reduced mobility of neonates.

Results of four years' satellite tracking of elephants in northern Cameroon

Three elephant subpopulations are found in Waza NP: one occupying the northern part of during the wet seasonand migrating northwards to Kalamaloue at the beginning of the dry season; one residing year within Waza NP year; and a third using the central and southern part of the Park in the dry season and migrating to the south at the beginning of the rainy season. Animals from the third group cause extensive damage to crops in the Mindif region during the wet season. In order to find more of about the movements and home ranges of these animals 2 cows were radio collared and monitored using satellite and VHF telemetry during 1994-1997. The Maga Dam and irrigated rice scheme developed in the late 1970s had changed the ecology of the Chari-Logone floodplain and hence the lives of the southern elephant group. Artifical reflooding begun in 1994 changed the ecology again. This monitoring programme saw a change in habitat, but the increased forage in the Park did not decrease the migration of elephants to the south. More work on this conflict situation is needed.

Nocturnal behavior in a group of unchained female African elephants

Nocturnal behavior in a group of unchained female African elephants

Nocturnal behavior in a group of unchained female African elephants

The chaining of elephants at night is a common management strategy in zoos, yet the costs and benefits of such a strategy are relatively unknown. A study of three unchained female African elephants was undertaken to document their nocturnal behavior. The subjects were observed between the hours of 1800 and 0800 for 10 weeks in the summer of 1992 (total of 172 hr) and 14 weeks in the summer of 1994 (total of 153 hr). Scan data were collected every 5 min to gather information on activity budgets, social proximity, and space utilization. All-occurrence data were collected on social and non-social behaviors. In each year of the study, the subjects spent equivalent amounts of time eating, lying, standing, and walking. Additionally, subjects spent half of their time within one body length of another animal and utilized all three available enclosures. Social and non-social behaviors were frequent, and these data plus the activity profiles reveal the animals generally were most active between the hours of 1800 and 2400 and 0600 and 0700. The findings suggest that the use of no restraints is currently an effective strategy for this elephant group. The high activity levels observed during many of the early evening hours suggest that zoos could permit increased activity and social interactions by extending the hours when the elephants are unchained. Zoo Biol 18:101–109, 1999. © 1999 Wiley-Liss, Inc.

Food hiding and enrichment in captive Asian elephants

Asian elephants ( Elephas maximus) kept in zoos usually spend less time foraging than their wild conspecifics. In order to increase foraging in a group of captive Asian elephants, peanuts were hidden above a distinctive outdoor enclosure structure, the stone border. It was expected that the elephants would learn this association and increase food searching in the outdoor enclosure. After training, the elephants searched more above the stone borders than during baseline, which indicates that they learned the relationship between stone borders and peanuts. But hiding food did not enhance searching behaviour. Therefore, this method of food hiding did not represent an environmental enrichment.

Social behaviour and breeding physiology of a group of Asian elephants Elephas maximus at the Pinnawala Elephant Orphanage, Sri Lanka

In 1986 at the Pinnawala Elephant Orphanage, Sri Lanka, a study of 4.4 Asian elephants Elephas maximus was carried out to establish the physical and behavioural changes associated with the ♀ oestrous cycle and the ♂ must cycle. At Pinnawala the elephants are maintained in mixed‐sex groups which has resulted in successful breeding. This paper describes the management of elephants at the orphanage and details their social and reproductive behaviour. It is suggested that successive matings throughout the oestrous cycle and on multiple cycles may be required to ensure successful breeding.

Elephant decline in Lake Manyara National Park, Tanzania

SummaryThe population of African elephant (Loxodonta africana (Blumenbach)) in Lake Manyara National Park, northern Tanzania, declined from about 500 individuals in 1984, to about 150 in 1988 due to poaching (mortality rate about 60% p.a.). In 1991 the population had declined further to about 60 individuals (mortality rate about 30% p.a.). In 1984 and 1991 road counts in the park were conducted. In 1984 a total distance of 2705 km was covered which yielded sightings of 777 elephant groups. In 1991 this distance was 5486 km and only 53 groups were observed. In both years an average elephant was seen in a group of seven individuals. Poaching pressure, apparently, had no effect on average group sizes. Group size changes with season, both in 1984 and 1991. The smallest groups were observed during the dry season when Acacia tortilis pods provided a defendable resource.In 1984, elephant occurred significantly more than expected in groups of five‐nine individuals and less than expected in groups of one or two individuals or in groups larger than 16. This has been interprétéd as a confirmation of the family structure of elephant as reported in other studies. In 1991, elephant group sizes were distributed according to a model of random association of individuals, indicative of destruction of the social framework by poaching.RésuméLa population d'éléphants africains {Loxodonta africana Blumenbach) au Pare National du lac Manyara, au nord de la Tanzanie, a baissé de près de 5000 individus en 1984 à près de 150 en 1988, à cause du braconnage (taux de mortalité de près de 60% p.a.). En 1991, la population avait encore baissé jusqu'à environ 60 individus (taux de mortalité de prés de 30% p.a.). En 1984 et 1991, on a fait des comptages dans le pare par la route. En 1984, on a parcouru une distance totale de 2705 km et repéré 777 groupes d'éléphants. En 1991, cette distance a été portée a 5486 km, et on n'a observé que 53 groups. Les deux années, le groupe moyen comptait sept individus. La pression du braconnage ne semblait pas avoir d'effet sur la taille des groupes, mais celle‐ci changeait avec les saisons, tant en 1984 qu'en 1991. On observait les plus petits groupes en saison sèche, lorsque les gousses d'Acacia tortilis représented une ressource à défendre.En 1984, on rencontrait significativement plus de groupes de cinq à neuf éléphants qu'on ne l'aurait prévu, et moins de groupes de un ou deux et de plus de seize. On a interprété ceci comme une confirmation de la structure familiale des groupes d'éléphants dont parlent d'autres recherches. En 1991, la taille des groupes d'éléphants se répartissait selon un modéle aléatoire d'association d'individus, indiquant une destruction par le braconnage de la structure sociale.