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PubMed2004

Long-distance, low-frequency elephant communication.

The production, transmission, and reception of and the behavioral response to long-distance, low-frequency sound by elephants is reviewed. The structure of low-frequency calls generated by elephants is separated into the "source" and the "filter" roles played by the lungs, larynx and vocal track, the composition of the expired air and the ambient air temperature. Implications regarding the size, age, sex, sexual and physical status follow from the call structure and detection. Reception of the signal is discussed in terms of the characteristics of the elephant's ear with particular attention to the determination of the threshold of hearing and the ability to locate the source of low-frequency sounds. Factors which influence the transmission of near infrasound are related to atmospheric structure. The critical role played by the thermal stratification and vertical gradient and magnitude of the wind in determining both the range and the detection of a signal are discussed for open and closed elephant habitats. Infrasound plays a pervasive role in reproduction, resource utilization, avoidance of predation and other social interactions. Current and future technology can be expected to contribute to the detection and interpretation of elephant communication. This will aid in the understanding of behavior and in efforts to sustain the species.

Animal Communication↗
PubMed2006

Using morphometric and analytical techniques to characterize elephant ivory.

There is a need to characterize Asian elephant ivory and compare with African ivory for controlling illegal trade and implementation of national and international laws. In this paper, we characterize ivory of Asian and African elephants using Schreger angle measurements, elemental analysis {X-ray fluorescence (XRF), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and inductively coupled plasma-mass spectroscopy (ICP-MS)} and isotopic analysis. We recorded Schreger angle characteristics of elephant ivory at three different zones in ivory samples of African (n=12) and Asian (n=28) elephants. The Schreger angle ranged from 32 degrees to 145 degrees and 30 degrees to 153 degrees in Asian and African ivory, respectively. Elemental analysis (for Asian and African ivory) by XRF, ICP-AES and ICP-MS provided preliminary data. We attempted to ascertain source of origin of Asian elephant ivory similarly as in African ivory based on isotopes of carbon, nitrogen and strontium. We determined isotopic ratios of carbon (n=31) and nitrogen (n=31) corresponding to diet and rainfall, respectively. Reference ivory samples from five areas within India were analyzed using collagen and powder sample and the latter was found more suitable for forensic analysis. During our preliminary analysis, the range of delta13C values (-13.6+/-0.15 per thousand and -25.6+/-0.15 per thousand) and delta15N values (10.2+/-0.15 per thousand and 3.5+/-0.15 per thousand) were noted.

Africa↗
PubMed2005

Genomic inferences from Afrotheria and the evolution of elephants.

Recent genetic studies have established that African forest and savanna elephants are distinct species with dissociated cytonuclear genomic patterns, and have identified Asian elephants from Borneo and Sumatra as conservation priorities. Representative of Afrotheria, a superordinal clade encompassing six eutherian orders, the African savanna elephant was among the first mammals chosen for whole-genome sequencing to provide a comparative understanding of the human genome. Elephants have large and complex brains and display advanced levels of social structure, communication, learning and intelligence. The elephant genome sequence might prove useful for comparative genomic studies of these advanced traits, which have appeared independently in only three mammalian orders: primates, cetaceans and proboscideans.

Africa↗
PubMed2006

Dystocia following prolonged retention of a dead fetus in an Asian elephant (Elephas maximus).

A 32-year-old nulliparous female Asian elephant (Elephas maximus) showed signs of parturition 8 months later than predicted from the breeding records. However, while serosanguineous fluid, necrotic tissue and pieces of amnion were expelled, second-stage labor did not progress. Since the fetus was not found during an endoscopic examination of the vestibule, it was assumed that the elephant had calved unseen and she was returned to the forest to recuperate. Twelve months later, the elephant showed clear signs of second-stage labor accompanied by a bulge in the perineum and passage of keratinized nail through the vulva. A 35 cm episiotomy incision was made in the perineum just below the anus, via which chains were attached to the forelimbs of the fetus. Traction on the forelimbs alone proved insufficient to achieve delivery because the fetal head kept rotating and impacting in the pelvis. However, traction applied via a hook inserted behind the mandibular symphysis allowed the head to be elevated and extended, and the fetus to be delivered. The episiotomy wound was sutured in two layers and although the skin did not heal during primary closure it subsequently healed uneventfully by second intention. Retrospective evaluation of the elephant's serum progestagens profile demonstrated a fall to baseline at the suspected onset of parturition, supporting the supposition that the fetus was retained in the uterus for 12 months after parturition began. It is suggested that serum progestagens concentrations should be monitored regularly in mated elephant cows to verify the establishment of pregnancy and to better estimate the expected timing, and the onset of calving.

Abortion, Missed↗
PubMed2006

Fatal enterocolitis in Asian elephants (Elephas maximus) caused by Clostridium difficile.

Two cases of fatal enteritis caused by Clostridium difficile in captive Asian elephants are reported from an outbreak affecting five females in the same zoo. Post mortem examination including histopathology demonstrated fibrinonecrotic enterocolitis. C. difficile was isolated by selective cultivation from two dead and a third severely affected elephant. Four isolates were obtained and found positive for toxin A and B by PCR. All isolates were positive in a toxigenic culture assay and toxin was demonstrated in the intestinal content from one of the fatal cases and in a surviving but severely affected elephant. PCR ribotyping demonstrated that the C. difficile isolates shared an identical profile, which was different from an epidemiologically unrelated strain, indicating that the outbreak was caused by the same C. difficile clone. It is speculated that the feeding of large quantities of broccoli, a rich source of sulforaphane, which has been shown to inhibit the growth of many intestinal microorganisms may have triggered a subsequent overgrowth by C. difficile. This is the first report of C. difficile as the main cause of fatal enterocolitis in elephants. The findings emphasize the need to regard this organism as potentially dangerous for elephants and caution is recommended concerning antibiotic treatment and feeding with diets containing antimicrobials, which may trigger an expansion of a C. difficile population in the gut.

Animals↗
PubMed1993

Structure-dynamics-function relationships in Asian elephant (Elephas maximus) myoglobin. An optical spectroscopy and flash photolysis study on functionally important motions.

In this work we report the thermal behavior (10-300 K) of the Soret band lineshape of deoxy and carbonmonoxy derivatives of Asian elephant (Elephas maximus) and horse myoglobins together with their carbon monoxide recombination kinetics after flash photolysis; the results are compared to analogous data relative to sperm whale myoglobin. The Soret band profile is modeled as a Voigt function that accounts for the coupling with high and low frequency vibrational modes, while inhomogeneous broadening is taken into account with suitable distributions of purely electronic transition frequencies. This analysis makes it possible to isolate the various contributions to the overall lineshape that; in turn, give information on structural and dynamic properties of the systems studied. The optical spectroscopy data point out sizable differences between elephant myoglobin on one hand and horse and sperm whale myoglobins on the other. These differences, more pronounced in deoxy derivatives, involve both the structure and dynamics of the heme pocket; in particular, elephant myoglobin appears to be characterized by larger anharmonic contributions to soft modes than the other two proteins. Flash photolysis data are analyzed as sums of kinetic processes with temperature-dependent fractional amplitudes, characterized by discrete pre-exponentials and either discrete or distributed activation enthalpies. In the whole temperature range investigated the behavior of elephant myoglobin appears to be more complex than that of horse and sperm whale myoglobins, which is in agreement with the increased anharmonic contributions to soft modes found in the former protein. Thus, to satisfactorily fit the time courses for CO recombination to elephant myoglobin five distinct processes are needed, only one of which is populated over the whole temperature range investigated. The remarkable convergence and complementarity between optical spectroscopy and flash photolysis data confirms the utility of combining these two experimental techniques in order to gain new and deeper insights into the functional relevance of protein fluctuations.

Animals↗
PubMed2001

An overview of the central nervous system of the elephant through a critical appraisal of the literature published in the XIX and XX centuries.

The two species of elephants (Indian: Elephas maximus and African: Loxodonta africana) possess the largest brain among land mammals. Due to its size, the elephant brain is discussed in virtually every paper dealing with the evolution of the central nervous system of mammals and comparative brain size. Studies on the social habits of elephants also deal with the skills and the "intelligence" and brain size of these species. Yet most of the descriptions and conclusions reported in comparative studies rely on second-hand data derived from investigations performed several decades before, often dating as far back as the XIX century. Furthermore, many of the original papers actually describing gross and detailed features of the brain of elephants are either no longer available, are written in languages other than English, or are difficult to trace. The present study gives a short description of the anatomy of the central nervous system of elephants, with special attention to its distinctive features, reports all available literature on the subject, and briefly discusses its origins and rationale.

Animals↗
PubMed1998

Manual collection and characterization of semen from Asian elephants (Elephas maximus).

The implications of collecting semen from elephants for use in artificial insemination programs are profound in the context of propagating captive elephants. Using a manual manipulation technique, semen was collected and characterized from five adult Asian elephants (Elephas maximus) and ejaculate fluid was obtained from one castrated elephant bull. The penis was stimulated to protrusion and erection by rectal massage of the pelvic portion of the urethra. During an ejaculatory response, massage was also directed onto the area of the ampulla of the ductus deferens. Sperm rich ejaculates were usually collected as a result of each ejaculatory contraction. Ejaculates were evaluated for spermatozoal concentration and pH (when possible) and sperm rich fractions combined for determination of total volume. Mean total volume of each collection was 27.5+/-4.4 ml. Mean concentration of the first and second ejaculatory responses from a collection was 2.05+/-0.17 x 10(9) and 1.34+/-0.19 x 10(9) sperm/ml, respectively. Measurement of seminal pH revealed no significant differences between the fractions. Mean pH of the first and second ejaculatory responses were 7.05+/-0.07 and 7.04+/-0.13. This method of collecting elephant sperm can be utilized for semen evaluation of bulls of unknown reproductive status in conjunction with other evaluation techniques (i.e. ultrasonographic, endocrinologic). It also has the potential for providing valuable genetic material for genome resource banks and for use with assisted reproductive techniques like artificial insemination.

Animals↗
PubMed2003

Fetal lung development in the elephant reflects the adaptations required for snorkeling in adult life.

The adult elephant is unique among mammals in that the pleural membranes are thickened and the pleural cavity is obliterated by connective tissue. It has been suggested that this peculiar anatomy developed because the animal can snorkel at depth, and this behavior subjects the microvessels in the parietal pleura to a very large transmural pressure. To investigate the development of the parietal pleura, the thickness of the endothoracic fascia (ET) was measured in four fetal African elephants of approximate gestational age 111-130 days, and the appearances were compared with those in human, rabbit, rat and mouse fetuses of approximately the same stage of lung organogenesis. The mean thicknesses of ET in the elephant, human, rabbit, rat and mouse were 403, 53, 29, 27 and 37 microm, respectively. This very early development of a thick parietal pleura in the elephant fetus is consistent with the hypothesis of a long history of snorkeling in the elephant's putative aquatic ancestors.

Adaptation, Biological↗
PubMed2006

Endotheliotropic elephant herpes virus (EEHV) infection. The first PCR-confirmed fatal case in Asia.

Since 1995, 4 suspected cases of Endotheliotropic Elephant Herpes Virus (EEHV) infection, i.e. based on clinical presentation, have occurred in Asia without resulting in epidemic outbreaks as expected. In order to confirm the presence of EEHV on the continent of Asia, viral DNA particles from liver samples of a wild-caught 3-year-old elephant found dead at a Cambodian elephant sanctuary and clinically diagnosed with EEHV, were PCR processed using known EEHV strain primers. The presence of EEHV viral nucleic acids was confirmed and the nucleic acids had a 99% sequence similarity to the U.S.A strain (gene bank locus: AF117265) and 97% sequence similarity to the European strain (gene bank locus: AF354746) assigning this case to the EEHV-1 cluster. More than the confirmation of EEHV on the continent of Asia, is the phylogenic relationship to the USA and European strains with no corresponding contact or transport of USA or European elephants to Asia. Thus, this brings many of the traditional theories into question. Although almost forgotten, this disease is still ramped in captive elephant populations worldwide and continues to devastate particularly the neonatal and weaning-age population. Special attention and continued research are needed specifically in the area of basic virology and epidemiology.

Animals↗
PubMed1997

Purification, identification, concentration and bioactivity of (Z)-7-dodecen-1-yl acetate: sex pheromone of the female Asian elephant, Elephas maximus.

In their natural ecosystems, adult male and female Asian elephants, Elephas maximus, live separately. For several weeks prior to ovulation, female elephants release a substance in their urine which elicits a high frequency of non-habituating chemosensory responses, especially flehmen responses, from male elephants. These responses occur prior to, and are an integral part of, mating. Using bioassay-guided fractionation, quantitatively dependent on these chemosensory responses, a specific sex pheromone was isolated and purified by an alternating series of organic and/or aqueous extractions, column chromatography, gas chromatography and high-performance liquid chromatography. Using primarily 1H-proton nuclear magnetic resonance (NMR) spectrometry and gas chromatography-mass spectrometry (GC-MS) of the urine-derived pheromone and its dimethyl disulfide derivative, we determined the structure of the active compound to be (Z)-7-dodecen-1-yl acetate (Z7-12:Ac). Concentrations of Z7-12:Ac in the female urine increased from non-detectable during the luteal phase to 0.48 microgram/ml (0.002 mM) early in the follicular phase and to 33.0 micrograms/ml (0.146 mM) just prior to ovulation. Bioassays with commercially available authentic synthetic Z7-12:Ac, using 10 Asian male elephants at several locations in the US, demonstrated quantitatively elevated chemosensory responses that were robust during successive tests, and several mating-associated behaviors. Bioassays with Z7-12:Ac with adult male elephants dwelling in more natural social situations in forest camps in Myanmar revealed some differing contextual pre-mating behavioral components. The remarkable convergent evolution of this compound suggests that compounds identified in mammalian exudates that are also present in pheromone blends of insects should be re-evaluated as potential mammalian chemosignals.

Animals↗
PubMed2003

Frontalin: a chemical message of musth in Asian elephants (Elephas maximus).

Musth is an important male phenomenon affecting many aspects of elephant society including reproduction. During musth, the temporal gland secretions (as well as the urine and breath) of adult male Asian elephants (Elephas maximus) discharge a variety of malodorous compounds together with the bicyclic ketal, frontalin. In contrast, teenage male elephants in musth release a sweet-smelling exudate from their facial temporal gland. We recently demonstrated that the concentration of frontalin becomes increasingly evident as male elephants mature. In the present study, we demonstrate that behaviors exhibited towards frontalin are consistent and dependent on the sex, developmental stage and physiological status of the responding conspecific individual. To examine whether frontalin functions as a chemical signal, perhaps even a pheromone, we bioassayed older and younger adult males, and luteal- and follicular-phase and pregnant females for their chemosensory and behavioral responses to frontalin. Adult males were mostly indifferent to frontalin, whereas subadult males were highly reactive, often exhibiting repulsion or avoidance. Female chemosensory responses to frontalin varied with hormonal state. Females in the luteal phase demonstrated low frequencies of responses, whereas pregnant females responded significantly more frequently, with varied types of responses including those to the palatal pits. Females in the follicular phase were the most responsive and often demonstrated mating-related behaviors subsequent to high chemosensory responses to frontalin. Our evidence strongly suggests that frontalin, a well-studied pheromone in insects, also functions as a pheromone in the Asian elephant: it exhibits all of the determinants that define a pheromone and evidently conveys some of the messages underlying the phenomenon of musth.

Aging↗
PubMed2007

Foetal age determination and development in elephants.

Elephants have the longest pregnancy of all mammals, with an average gestation of around 660 days, so their embryonic and foetal development have always been of special interest. Hitherto, it has only been possible to estimate foetal ages from theoretical calculations based on foetal mass. The recent development of sophisticated ultrasound procedures for elephants has now made it possible to monitor the growth and development of foetuses of known gestational age conceived in captivity from natural matings or artificial insemination. We have studied the early stages of pregnancy in 10 captive Asian and 9 African elephants by transrectal ultrasound. Measurements of foetal crown-rump lengths have provided the first accurate growth curves, which differ significantly from the previous theoretical estimates based on the cube root of foetal mass. We have used these to age 22 African elephant foetuses collected during culling operations. Pregnancy can be first recognized ultrasonographically by day 50, the presumptive yolk sac by about day 75 and the zonary placenta by about day 85. The trunk is first recognizable by days 85-90 and is distinct by day 104, while the first heartbeats are evident from around day 80. By combining ultrasonography and morphology, we have been able to produce the first reliable criteria for estimating gestational age and ontological development of Asian and African elephant foetuses during the first third of gestation.

Animals↗
PubMed1991

Synthesis and receptor binding activity of elephant beta-endorphin, a beta-endorphin homolog with highly potent analgesic activity.

Elephant beta-endorphin and its analog, elephant beta-endorphin(6-31) were synthesized by standard solid phase method. Receptor binding activity showed that elephant beta-endorphin was five to six times more potent than human beta-endorphin in its ability to bind to opiate receptors on rat brain membrane. In a previous study (Wong, C.-L., Wai, M.-K., Cheng, H.-C., Chung, D. & Yamashiro, D (1990) Clinical and Experimental Pharmacology and Physiology 16, 33-37), tail flick test for intracerebroventricularly administered beta-endorphin showed that the antinociceptive potency of elephant beta-endorphin was seven to eight times higher than that of human beta-endorphin in mice. Results from both studies suggest that elephant beta-endorphin was a much more potent antinociceptive agent than human beta-endorphin in tail flick test and its higher analgesic activity might be due to its higher affinity for opiate receptors in the brain.

Amino Acid Sequence↗
PubMed1990

Preliminary study on the antinociceptive effect of elephant beta-endorphin.

1. Intraventricular administration of human beta-endorphin and elephant beta-endorphin significantly prolonged the tail flick response tested 30 min later. However, elephant beta-endorphin was about 7-8 times more potent than human beta-endorphin in the tail flick test. 2. beta-Endorphin antagonized the antinociceptive effect of both human beta-endorphin and elephant beta-endorphin by the same extent. Naloxone also antagonized the antinociceptive effects of the beta-endorphins but it was less effective than beta-endorphin. 3. Human beta-endorphin and elephant beta-endorphin were of equal potency in inhibiting the abdominal constriction response induced by intraperitoneal (i.p.) acetic acid. Both beta-endorphin and naloxone antagonized these effects of the beta-endorphins with naloxone being more effective. 4. The present study showed that different opioid receptor subtypes may be involved in the tail flick test and the abdominal constriction test. Furthermore, elephant beta-endorphin was a better antinociceptive agent than human beta-endorphin in the tail flick test.

Analgesics↗
PubMed2006

The structure of the cushions in the feet of African elephants (Loxodonta africana).

The uniquely designed limbs of the African elephant, Loxodonta africana, support the weight of the largest terrestrial animal. Besides other morphological peculiarities, the feet are equipped with large subcutaneous cushions which play an important role in distributing forces during weight bearing and in storing or absorbing mechanical forces. Although the cushions have been discussed in the literature and captive elephants, in particular, are frequently affected by foot disorders, precise morphological data are sparse. The cushions in the feet of African elephants were examined by means of standard anatomical and histological techniques, computed tomography (CT) and magnetic resonance imaging (MRI). In both the forelimb and the hindlimb a 6th ray, the prepollex or prehallux, is present. These cartilaginous rods support the metacarpal or metatarsal compartment of the cushions. None of the rays touches the ground directly. The cushions consist of sheets or strands of fibrous connective tissue forming larger metacarpal/metatarsal and digital compartments and smaller chambers which were filled with adipose tissue. The compartments are situated between tarsal, metatarsal, metacarpal bones, proximal phalanges or other structures of the locomotor apparatus covering the bones palmarly/plantarly and the thick sole skin. Within the cushions, collagen, reticulin and elastic fibres are found. In the main parts, vascular supply is good and numerous nerves course within the entire cushion. Vater-Pacinian corpuscles are embedded within the collagenous tissue of the cushions and within the dermis. Meissner corpuscles are found in the dermal papillae of the foot skin. The micromorphology of elephant feet cushions resembles that of digital cushions in cattle or of the foot pads in humans but not that of digital cushions in horses. Besides their important mechanical properties, foot cushions in elephants seem to be very sensitive structures.

Adipose Tissue↗
PubMed2006

A simple and inexpensive molecular method for sexing and identification of the forensic samples of elephant origin.

The population of the Asian elephant is being dramatically reduced due to poaching of the ivory from the male. As poaching occurs in remote forests, it often takes weeks or longer for it to be discovered and it is therefore often very difficult to determine the sex of the decomposed body. Data suggest that in the recent past, over 2000 male elephants have been poached in South India. We have developed a technique based on molecular markers to determine that the carcass is an elephant and that it is a male. Using DNA sequence information from Genbank, we have developed two primer pairs: one for the mitochondrial DNA (mtDNA) and the other for the sex-determining region of Y chromosome (SRY) gene of the Indian elephant. After PCR amplification of known elephant DNA, we found that the mtDNA was common in both males and females, whereas the SRY-specific amplicon was observed only in the male.

Animals↗
PubMedDate not supplied

Radiographic diagnosis of lameness in African elephants (Loxodonta africana).

Lameness in captive elephants is most commonly caused by pododermatitis or degenerative joint disease. Hard surfaces such as concrete, which produce a damp and cold environment, wet and muddy conditions, as well as restricted movement are the major causes of these problems. Radiography was performed in two African elephants at the Schoenbrunn Zoo in Vienna to determine the cause and extent of lameness. Various radiographic techniques are described for use in trained elephants. Low time settings were used to avoid loss of detail through movement and to minimize exposure while observing radiation safety. A 37-year-old elephant had front limb lameness due to an interdigital abscess. In radiographs of the foot an inhomogenous soft-tissue swelling without involvement of the phalanges was seen. Ultrasonography was helpful in visualizing the fluid-filled abscess. In additional joint radiographs severe degenerative joint disease was identified. A 13-year-old elephant had lameness of the hind limb. Radiographs of the hind limb from the foot to the stifle were made. Open physes and early signs of degenerative joint disease were identified on the radiographs.

Animals↗