Captive African Elephants Research Articles

QUANTIFYING ACOUSTIC AND TEMPORAL CHARACTERISTICS OF VOCALIZATIONS FOR A GROUP OF CAPTIVE AFRICAN ELEPHANTS LOXODONTA AFRICANA

ABSTRACT In order to increase understanding of African elephant vocal communication and to standardise the terminology used to describe vocalisations, this study examined acoustic and temporal characteristics of 983 vocalisations from 2 male and 6 female captive African elephants. Recording collars were used to monitor vocalisations and videotape to simultaneously record behaviour, allowing for unambiguous attribution of sounds to individuals, even in close proximity. Eight acoustically distinct categories of calls were defined in terms of structural characteristics; two of these categories are described for the first time. Low-frequency vocalisations containing infrasonic components were predominant in this localised communication context and showed a gradation of variation in acoustic structure and duration. Most calls were part of temporally closed exchanges between individuals and coincided with short-distance interactions. In addition, male-female choruses and non-musth rumbles from males were documented, suggesting that the African elephant vocal repertoire may be more complex than previously reported.

Assessment of testicular endocrine function in captive African elephants by measurement of urinary and fecal androgens

AbstractAndrogen measurements in urine and/or feces represent a potentially important tool for monitoring testicular endocrine function in the African elephant. To assess the feasibility of this approach, the aims of the present study were to: 1) examine the presence and relative abundance of immunoreactive testosterone (iT) and its 5α‐reduced 17‐oxometabolite epiandrosterone (iEA) in African elephant excreta, and 2) compare urine and fecal androgen profiles in animals of different ages and during the musth and non‐musth condition. Urine and fecal samples were collected over periods of up to 3 years from five bulls (ages 7–24 years) living in three mixed social groups. In parallel, indications of musth were recorded by keeper staff as an independent marker of male androgen status. Measurements of iT and iEA were carried out by enzymeimmunoassay (EIA) following methanolic extraction of hydrolyzed urine and lyophilized fecal powder. High‐pressure liquid chromatography (HPLC) of musth phase samples confirmed the presence of substantial quantities of testosterone (T) and epiandrosterone (EA) in both urine and feces. EA was predominant in feces, whereas T was more abundant in urine. In each male, the two androgen measures were significantly correlated (feces, r = 0.71–0.93, P < 0.0001; urine, r = 0.86–0.91, P < 0.0001), as were fecal and urinary concentrations of each of the two androgens measured (r = 0.35–0.77, P < 0.0001). Moreover, in the two oldest males that showed clear signs of musth, levels of iEA and iT were markedly elevated during musth compared to non‐musth periods (differences were significant for feces in both animals, but in urine only for one). Collectively, the data show that measurement of urinary and fecal androgens generates useful information on gonadal status in male African elephants, and as such should provide new opportunities to improve the management and welfare of bulls maintained in captivity, as well as to examine physiological correlates of reproductive function in free‐ranging animals. Zoo Biol 21:27–36, 2002. © 2002 Wiley‐Liss, Inc.

The Elephant's Foot: Prevention and Care of Foot Conditions in Captive Asian and African Elephants

The Elephant's Foot: Prevention and Care of Foot Conditions in Captive Asian and African Elephants

The measurement of glucocorticoid concentrations in the serum and faeces of captive African elephants (Loxodonta africana) after ACTH stimulation.

Conventionally, the assessment of adrenal responses to stress relies on blood sample collection. However, blood collection from animals is impossible without restraint or immobilisation that influences results. This study was undertaken to validate recently established enzyme immunoassays that measure faecal glucocorticoid metabolites in elephants, and to perform a preliminary investigation into the biological relevance of this non-invasive method for use in assessing the degree of stress in this species. Four juvenile African elephants were injected i.m. with 2.15 mg synthetic adrenocorticotrophic hormone (Synacthen, Novartis, Switzerland). Blood and faecal samples were collected over 4 h and 7 d respectively. Concentrations of serum cortisol and faecal cortisol metabolites were determined using immunoassay. Variability of basal and peak values in blood and faeces was observed among the elephants. After ACTH injection, serum cortisol concentrations increased by 400-700%. An 11-oxoaetiocholanolone enzyme immunoassay (EIA) proved best suited to measure cortisol metabolites (11,17-dioxoandrostanes) when compared to a cortisol and corticosterone EIA in faecal samples. Concentrations of faecal 11,17-dioxoandrostanes increased by 570-1070%, reaching peak levels after 20.0-25.5 h. Greater levels of glucocorticoid metabolites were measured in faecal samples from elephants kept in small enclosures compared to levels in the faeces of animals ranging over a larger area. The results of this preliminary study suggest that non-invasive faecal monitoring of glucocorticoid metabolites is useful in investigating adrenal activity in African elephants.

Endocrine and ultrasound evaluation of a non-cycling African elephant: Identification of an ovarian follicular cyst

The reproductive rate of captive African elephants is low because of logistical difficulties associated with transporting animals for breeding, the danger of maintaining bulls and medical or physiological problems. There also is growing evidence that a significant number of mature female elephants are not experiencing normal estrous cycles. The case described in this report involves the diagnosis and attempted treatment of an ovarian follicular cyst in an African elephant at the Pittsburgh Zoo. On the basis of serum progesterone analysis, the female exhibited regular ovarian cycles from July 1993 through March 1994, but from November 1994 to the present has not shown any evidence of reproductive cyclicity. In April 1996, a large follicular structure was identified on the right ovary using transrectal ultrasound. In an attempt to luteinize the cyst, 500 μg gonadotropin-releasing hormone (GnRH) was administered intravenously in October 1996, which stimulated a modest increase in serum luteinizing hormone (LH) (approximately twofold over baseline), but no resumption of ovarian activity. The elephant was treated again 5 months later with a higher dose of GnRH (5 mg, i.v.) with the same results. An ultrasound evaluation in July 1997 indicated the structure was still present. In October 1997, the female was given human chorionic gonadotropin (hCG; 10,000 IU, i.m.), which induced estrus and breeding, but no ovulation or luteinization of the cyst, and she remains acyclic. These results suggest that conventional methods developed in other species for treating ovarian follicular cysts may not necessarily be effective in the elephant. It is also important that reproductive age females be monitored via continuous progesterone analysis and occasional reproductive tract ultrasound evaluations to understand better the etiology of ovarian dysfunction so that effective treatments can be developed to induce consistent ovarian activity. Zoo Biol 18:223–232, 1999. © 1999 Wiley-Liss, Inc.

Tool use by wild and captive elephants

Abstract. This study describes the tool-use potentials of captive African and Asian elephants, Loxodonta africana and Elephus maximus, respectively, and wild African elephants and explores the ecological and evolutionary significance of this behaviour. Comparison of the types, diversity and frequency of tool use by captive and wild elephants with other known tool-using mammals is offered as a means for evaluating the evolutionary significance of tool-using behaviour. Several hypotheses concerning the origin and evolutionary significance of tool use are examined, and it is proposed that in elephants, tool use may serve as adaptations enabling these furless, large-bodied tropical land mammals to cope with ectoparasites and thermoregulation.

Responses of captive African elephants to playback of low-frequency calls

We conducted a series of playback trials with captive African elephants to identify behaviors that might indicate perception of calls by conspecifics. Our findings were as follows. (i) The elephants responded clearly to playbacks of prerecorded low-frequency elephant calls. Responses included, in rough sequence, lifting and stiffening of ears, vocalization, walking or running towards the concealed speaker, clustering in a tight group, and remaining motionless ("freezing"), with occasional scanning movements of the head. The occurrence of each of these behaviors increased substantially immediately after the playbacks. (ii) Elephants responded both to full-bandwidth playbacks and to playbacks of calls in which most of the energy above 25 Hz was filtered out, simulating the effect of frequency-dependent attenuation over distance. (iii) Elephants did not respond to a pure-tone control stimulus similar in frequency and intensity to the filtered elephant calls. Thus, the observed responses to elephant calls were not merely responses to an unexpected stimulus, but probably indicate recognition of a biologically meaningful signal.

Urinary androstenedione and luteinizing hormone concentrations during musth in a mature African elephant

AbstractMusth has not been well documented in captive African elephants. A 37‐year‐old African bull elephant in the Kansas City Zoological Park was observed during periods of behavioral musth and non‐musth. Androstenedione and luteinizing hormone (LH) concentrations in urine were measured by radioimmunoassay. Urinary androstenedione and LH levels were significantly higher in musth urine than in non‐musth samples. A positive correlation (P > 0.001) existed between urinary LH and androstenedione concentrations. These results indicate that musth can occur in a zoo‐maintained African elephant and that urinary androgen levels are elevated during musth, possibly as the result of LH stimulation of testicular steroidogenesis.

Synchronization of defaecation in the African elephant ( Loxodonta africana )

The ecological significance of defaecation in African elephants (Loxodonta africana) has been discussed from a number of points of view. Dropping counts have been used to investigate population size and movements (Wing & Buss, 1970; Laws, Parker & Johnstone, 1975); the chemical composition of dung has been examined (Dougall, 1963; Weir, 1972); and dung decomposition and its role in nutrient cycles have been described (Anderson & Coe, 1974). Defaecation in captive African elephants has been examined (Coe, 1972) and food consumption of wild elephant herds has been calculated from data on gross assimilation efficiency and dung production (Coe, 1972; Rees, 1982). This paper presents evidence of a synchronization of defaecation in elephants and discusses its possible ecological significance.

Gross assimilation efficiency and food passage time in the African elephant

SummaryThe amount of food consumed and dung voided by two captive African elephants was measured over a period of 7 days. The mean gross assimilation efficiency of the two elephants was calculated to be 22.4%. The food passage time was between 21.4 and 46 h for one elephant. Previous estimates of food consumption by wild elephants, based on an earlier, higher estimate of assimilation efficiency, are considered to be too high and have been recalculated.RésuméLa quantité de nourriture consommée et de féces rejetées par deux éléphants captifs d'Afrique a été mesurée durant sept jours. On a calculé que l'efficience moyenne d'assimilation par les deux animaux est de 22.4%. La durée du transit de la nourriture est comprise entre 21.4 et 46 h pour un éléphant. Des estimations de la consommation chez les élephants sauvages basée sur une estimation antérieure bien plus élevée de l'efficience d'assimilation ont été considérées comme étant trop élevées et ont été recalculées.

An Unusual Method of Feeding Behavior in Captive African Elephants

An unusual feeding behavior was observed in a small herd of African elephants at the Safari Park, Ramat Gan, Israel. An elephant was observed to insert her trunk into the rectum of other elephants in order to obtain undigested food. This behavior was studied in relation to the hierarchy of the elephants within the herd. Half a year of observation led us to conclude that the elephant higher in hierarchical level would insert her trunk into the rectum of elephants lower in the hierarchy. The reverse was not observed.

Behavior Associated with Feeding in Captive African and Asian Elephants

Elephants' use of their trunks during feeding in captivity is described. African and Asian elephants differ not only in trunk morphology but also in trunk behavior. African elephants pick up objects using a "pinch" while Asians rely mostly on a "grasp." Asians normally use their feet to secure objects while Africans use their tusks. The first documented case of Africans using their feet is reported. Laterality or "handedness" is also reported for the first time in elephants. A survey of several zoos and circuses showed this phenomenon to be widespread in captivity. A female African elephant who was intensively studied showed lateral preferences for many different components of her feeding behavior.

Salmonella infection in the African elephant and the black rhinoceros.

Salmonellosis in two captive African elephants and a black rhinoceros is described. Necropsy findings and characters of the salmonellae isolated are outlined. Possible sources of infection are discussed and on the basis of their findings, the authors make recommendations for the care of newly captured wild animals.

Notes on the teeth and ovaries of an African elephant (Loxodonta africana) of known age

A captive female African elephant, known to be 27 years old, died as a result of trauma. Her growth rate was similar to that of other captive African elephants, and slightly greater than that of wild animals. The 5th molar was in full wear, and the 6th was just coming into wear. There was extensive dental caries of the labial, lingual and occlusal surfaces of the 5th molars, presumably due to the unnatural diet. The ovaries contained a number of large cystic follicles, and at least 50 regressing corpora lutea. These abnormalities are probably related to the fact that the elephant had never been mated.