Captive elephants

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An elephant carrying tourists sitting on a howdah.

Elephants can be found in various captive facilities such as a zoo, sanctuary, circus, or camp, usually under veterinary supervision. They can be used for educational, entertainment, or work purposes. The earliest evidence of captive elephants dates to the Indus Valley Civilization about 4,500 years ago. Since then, captive elephants have been used around the world in war, ceremony, and for manual labor and entertainment.[1] Captive elephants have been kept in animal collections for at least 3,500 years. The first elephant arrived in North America in 1796.[1] London Zoo, the first scientific zoo, housed elephants beginning in 1831.[2]

Before the 1980s, zoos obtained their elephants by capturing them from the wild. Increased restrictions on the capture of wild elephants and dwindling wild populations caused zoos to turn to captive breeding.[3] The first successful captive birth in North America of an Asian elephant occurred at Oregon Zoo in 1962, while the first African elephant captive birth occurred at Knoxville Zoological Gardens in 1978.[3] Today, most zoos obtain their elephants primarily through breeding, though occasionally zoos will obtain elephants from semi-captive work camps in Asia or rescue elephants that would otherwise be culled in Africa.[4][5] Without an increase in birth rates or an influx of wild elephants, practitioners fear that captive elephant populations could become non-viable within 50 years.[6]

In 2006, 286 elephants were kept in American zoos (147 African elephants and 139 Asian elephants).[7] Nearly one in three Asian elephants lives in captivity—about 15,000 in total—mostly in work camps, temples, and ecotourism sites in the countries in which they naturally occur.[8] The International Union for Conservation of Nature (IUCN) estimates the total population of Asian elephants in the wild is 40,000 to 50,000,[9] and that of African elephants in the wild is 400,000 to 600,000.[10]


An elephant wearing a caparison (decorative covering), 19th century, India.
Elephant drawing, c.1250, from historic writings by UK monk Matthew Paris

Tame elephants have been recorded since the Indus Valley civilization around 2,000 BCE. With mahouts, they have been used as working animals in forestry, as war elephants (by commanders such as Hannibal), for cultural and ceremonial use (such as temple elephants), as a method of execution, for public displays such as circus elephants, in elephant polo and in zoological gardens.

Sketch of Hanno, the pet white elephant of Pope Leo X, by Raphael, c.1514.

The expression white elephant derives from a white elephant being considered sacred and therefore disqualified from useful work, yet posing a large ownership cost.[11] The origin of the expression is from the story that the kings of Siam gave white elephants as a gift to courtiers they disliked, in order to ruin the recipient by the great expense incurred in maintaining the animal.[12]

Behaviour and training[edit]

An elephant painting.
A temple elephant being washed at a Hindu temple in Kanchipuram, Tamil Nadu.
black and white photograph of Sydney street parade with an elephant on a circus float
Elephant from Wirth's Circus in a Sydney street parade - taken in 1938

Elephants have the largest brains of all land animals, and ever since the time of Ancient Greek philosopher Aristotle,[13] have been renowned for their cognitive skills, with behavioural patterns shared with humans. Pliny the Elder described the animal as being closest to a human in sensibilities.[14] They also have a longer lifespan than most livestock. Elephants exhibit a wide variety of behaviors, including those associated with grief, learning, allomothering, mimicry, play, altruism, use of tools, compassion, cooperation, self-awareness, memory, and language.

In the wild, elephant herds usually consist of a matriarch that leads a stable group of related adult females and their young offspring. When male elephants reach maturity, they usually disperse from the herds where they were born and live on their own.[4] However, some males join groups called bachelor herds, where they associate with other males during the times of the year that they are not sexually active.[15] When males are sexually active, they enter a state called musth, during which time they roam widely, searching for available females. During this time, they are extremely aggressive toward other males they encounter.[16]

In captivity, providing elephants with a social structure that resembles a wild social structure is difficult, in part because moving elephants between different facilities to mimic male dispersal or facilitate breeding is a logistically challenging task,[17] but also because the extreme aggression of adult male elephants in musth poses a health and safety threat to keepers and other elephants alike.[4]


Elephants in captivity can be trained to perform a variety of tasks. In Nepal, for example, elephants are ridden by forest rangers to patrol national forests and for entertainment by tourists.[18] In Myanmar, elephants assist in logging operations.[19] In North America, Australasia, and Europe, elephants are primarily trained for circuses, where they may be trained to perform tricks for the entertainment of crowds, and in zoos, where they may be trained to participate in their own husbandry by, for example, presenting their feet for nail trims or opening their mouth for dental exams.[4] The use of elephants in circuses is controversial; public outcry caused Ringling Bros. and Barnum & Bailey circuses in the United States to commit to retiring their elephants to a private sanctuary in 2015.[20]

There are three primary training styles that can be used either separately or together in elephant facilities, each with its own pros and cons for elephant welfare and human safety:[4]

  • Free contact- The elephant is handled directly and the elephant and keeper share the same space while they interact. Some facilities use free contact to allow their elephants a great deal of physical freedom, for example leading elephants on walks. Increased exercise of this type can prevent elephants from gaining excessive weight, which can lessen the instance of health problems in joints and feet.[4] Access to medical examination is also unparalleled with free contact systems--veterinarians and keepers can train free contact elephants to allow for many kinds of medical examinations, including dental procedures and blood draws.[21] However, free contact is controversial among practitioners and the public. It requires the use of ankuses, also known as guides, bullhooks, or goads. An ankus consists of a hook attached to a handle and is used in training to guide elephants into the correct position.[21] The ankus can be used on occasion for physical punishment.[21] Additionally, free contact can pose a danger to handlers. All elephants, but especially males in musth, pose hazards to people. There have been several incidents of elephants killing handlers and keepers when being worked in a free contact system.[22][23][24] The Association of Zoos and Aquariums (AZA) in the United States is phasing out the use of free contact with elephants in its member zoos.[25]
  • Protected contact- Elephant and keeper never share the same unrestricted space. Instead, keepers interact with elephants through a barrier, and elephants are free to leave the contact area at will.[4] Elephants in a protected contact situation are typically trained through a positive reinforcement system with rewards when training progress is achieved.[21] Well-trained elephants in a protected contact system can allow veterinarians and handlers to have good access for routine care, though not as comprehensively as in free contact systems.[21] Some elephants, especially ill elephants that may not be capable of entering the protected contact area and young elephants that have not yet been trained for protected contact, may be harder to access for veterinary care in a protected contact facility. Protected contact facilities are also unable to take their elephants for walks, which may increase the incidence of obesity and health problems in their elephant populations.[4]
  • No contact- No elephant handling takes place unless the elephant is under chemical sedation.[4] Elephants can be moved from one place to another by allowing and disallowing access to different locations, but any medical care or routine maintenance must occur under sedation. The AZA does not allow no contact systems in their member zoos, as they require all elephants to be trained to participate in their own care, including presenting their feet for nail trims, allowing for exams of their ears, eyes, mouth, and teeth, and allowing their blood to be collected.[26] Chemical sedation of an elephant is risky and can cause harm to the animal or to the people immobilizing the animal.[1] As such, minimizing the need for anesthesia as much as possible is desirable in most situations. The lack of training in no contact systems also means that elephants do not receive the enrichment benefits that come with regular voluntary training with positive reinforcement.[4][27] Despite these concerns, some facilities use no contact systems for particularly aggressive or dangerous elephants, particularly males during musth.[4]

Some facilities will use a combination of these handling methods, and will for example use free contact with their female elephants and protected contact with their more dangerous males.[4]


Most elephant populations in captivity in North America, Europe, and Asia are not self-sustaining, meaning that without an increase in birth rates or importation of wild individuals, some captive populations will be extinct within 50 years.[6][28] Some hurdles to captive reproduction include female infertility (the causes of which are not fully understood) and an overrepresentation of males in the captive population.[29][30]

As such, substantial effort has gone into increasing the birth rate in captive elephant populations. Due to the size, intelligence, and strong social bonds of elephants, moving elephants from facility to facility for the purpose of breeding can engender severe logistic hurdles and cause stress to the elephants moved, as well as the elephants present in the new facility.[17] It may be preferable to relocate young males, who would naturally disperse away from their herds of birth in the wild, as opposed to females, who would normally stay with their herd of birth for life in the wild.[4]

Because of the stress and logistics involved in moving elephants from one facility to another, some managers are turning to artificial insemination to produce offspring.[31] Semen may be collected from males in other collections or from wild males to further increase the genetic diversity of the captive population.[32]


Successful hand-rearing of orphaned calves depends critically on the milk formula used. Human infant formula is commonly used, but requires to be supplemented with bovine colostrum (commercially available in substitute form), and lactobacillus to protect the gastrointestinal tract. To provide additional fat, desiccated coconut and butterfat are added, with vitamin and mineral supplements, in particular vitamin E, vitamin B, and calcium. Rice water strained from cooked rice and glutinous rice broth are useful and are added to the formula to combat diarrhea. Rice cereal, milled whole barley or oatmeal, desiccated coconut, and other ground solid foods are added to the milk of older calves to ease the transition to solid foods.[33]

Professor Niels Bolwig at Ibadan University, Nigeria in 1963 successfully reared an orphaned infant elephant from a few days old by developing his own rich milk formula consisting of cows' milk and butter fat. This is believed to be the first successful rearing. Until then most rearing attempts had been unsuccessful due to diet intolerance.


Elephants are complex animals with many varied welfare requirements in captivity.[4] Principles of animal welfare dictate that animals should be housed in appropriate environments with consideration for species-typical biology and behavior.[34]

Animal welfare concerns about elephants in captivity stem from the uniqueness of elephants' social structure, biology, size, and spatial requirements.[7] In the wild, elephants can walk 50 miles a day,[7] while the Association of Zoos and Aquariums (AZA) in the United States recommends a minimum of 5400 ft2 (500 m2) of space per elephant in outdoor habitats for their member zoos.[26] Proponents of elephants in zoos argue that wild elephants walk long distances because of the necessity of finding water, food, or mates, but that captive elephants do not require the same amount of walking if resources are more readily available.[7]

In the wild, elephant herds (particularly those of African elephants) can be quite large.[4] The AZA requires their member facilities to house at least three females, two males, or three mixed-sex individuals in order to mimic wild herd structure, though this is much smaller than many wild herds.[26] In 2008, a study of mainly European and North American zoos found that one-fifth of elephants in these zoos lived alone or with only one other elephant and that the mean number of elephants held in these zoos was 4.28.[35] In recent years, there has been some progress in integrating smaller elephant herds across different zoos into larger groups, though advancement in this area is ongoing.[35]

There has been some effort to understand which behaviors in captive elephants indicate good welfare and which indicate welfare concerns. In 2015, the Department for Environment, Food, and Rural Affairs (DEFRA) in the United Kingdom developed a set of indicators that practitioners and oversight bodies can use to determine the state of an individual elephant's welfare in captivity. This report was compiled in response to an earlier government report that indicated that many elephants in UK zoos experienced issues with foot health, obesity, and stereotypies. Important indicators of welfare included:[36]

  • Stereotypies: including head bobbing, swaying, and pacing (as a negative indicator of welfare)
  • Comfort behavior: including wallowing, swimming, and dust bathing (as a positive indicator of welfare)
  • Feeding (as a positive indicator)
  • Interacting with the environment (as a positive indicator)
  • Interacting with other elephants (as a positive indicator, except for excessive aggression, which is a negative indicator)


Infectious diseases[edit]


According to a report published by the Center for Disease Control, in North America, approximately 2% of African, and 12% of Asian captive elephants are thought to be infected with tuberculosis.[37]

In 2012, two elephants in Tete d’Or Zoo, Lyon (France), were diagnosed with tuberculosis. Due to the threat of transmitting tuberculosis to other animals or visitors to the zoo, their euthanasia was initially ordered by city authorities but a court later overturned this decision.[38]

At an elephant sanctuary in Tennessee, a quarantined 54-year-old African elephant being treated for tuberculosis was considered to be the source of latent (inactive) tuberculosis infections in eight workers.[37][39]

Elephant endotheliotropic herpesvirus[edit]

Elephant endotheliotropic herpesvirus (EEHV) is a family of herpesviruses that have been known to cause the death of more than 100 young Asian elephant calves in the wild and in captivity since 1988.[40] In North America, EEHV has been responsible for 58% of the deaths of Asian elephants in captivity between the ages of 4 months and 15 years that were born between 1962 and 2007.[40] EEHV has also caused the death of Asian elephant calves in captivity in Europe[41] and Asia,[42] as well as wild calves.[43]

The first recognized fatal case of EEHV in an Asian elephant was identified at the National Zoo in Washington, D.C. in 1995, but subsequent investigation of stored tissue samples found evidence of fatal cases of EEHV in captivity dating back to at least 1988.[44] Testing has shown that these viruses appears to be carried in latency (without symptoms) in most Asian and African elephant adults, and that these adults tend to become infectious when they experience stress or excitement, including after the birth of a calf.[40][45] Asian elephant calves are extremely susceptible to the virus during the period after they have been weaned from their mother's milk, when they are no longer protected by maternal antibodies.[46] Active EEHV infection causes small nodules on the head and trunk, and inside the lungs of individuals with mild cases.[40]

In fatal attacks (usually caused by the EEHV 1A strain),[46] the virus acts quickly, usually causing death within one hour to seven days within the onset of symptoms when untreated.[47] Symptoms include lethargy, unwillingness to eat, lameness, colic, and diarrhea.[47] The virus causes widespread hemorrhaging of endothelial tissue.[40]

There is no cure for EEHV, but zoos have developed some treatments that have shown some effectiveness in suppressing the virus and preventing fatality.[46] The European Association of Zoos and Aquaria's (EAZA) treatment guidelines recommend administering fluid therapy, fresh plasma from adult elephants that have antibodies against the virus, and antiviral drugs including famciclovir, ganciclovir, or acyclovir.[48] Of elephants that have been treated for severe EEHV, there is an approximate 40% survival rate.[46]

Noninfectious diseases[edit]

Foot and musculoskeletal diseases[edit]

In 2006, a study found that 33% of North American zoos reported at least one elephant with a foot abnormality, 36% reported at least one elephant with arthritis, and 18% reported at least one case of lameness in their elephant populations within the previous year.[49]

Common foot problems among captive elephants include overgrown nails, soles, and cuticles, necrotic pododermatitis, the formation of abscesses, and split nails and soles.[4] Though these conditions do not usually cause mortality on their own, they are often the reason that captive facilities choose to euthanize their elephants due to quality of life concerns.[4] As such, many elephant facilities perform regular foot care in hopes of preventing serious, chronic foot problems. In the wild, elephants' feet are worn down as elephants walk, and the goal of captive foot care is to simulate this wearing-down effect.[4] Elephants in free contact or protected contact facilities can be trained to accept and assist with routine foot care, including nail filing and trimming of the foot pad.[4] Elephants that are not trained must be anesthetized to accept foot care, which brings an element of risk for elephant and handler alike.[4]

Common musculoskeletal problems include degenerative joint disease, osteoarthritis, trauma, and soft tissue strains.[50] Due to their large body mass and long life, elephants are thought to be especially prone to these problems as they age.[50] The relatively sedentary lifestyle of a captive elephant in comparison to its wild counterparts likely contributes to these issues.[50]

A 2016 study of North American zoos found that predictors of poor foot health included older age, more time spent on hard floors, less space in nighttime enclosures, and a high percentage of time spent in exhibits that allowed choice between being indoors or outdoors.[50] The same study found correlations between poor musculoskeletal health and more time spent on hard floors and lack of space in daytime exhibits.[50] It is thought that using soft sand on floors and providing access to grass, dirt, or sand outside, giving elephants increased space in their day and night enclosures, and avoiding large changes in temperature and humidity between indoor and outdoor spaces may improve foot and musculoskeletal health.[50]


A 2016 study of North American zoos found that 74% of zoo elephants were overweight or obese.[51] The effects of obesity on elephants have not been widely studied, but based on research in other species, it may be correlated with higher instances of infertility, arthritis, and cardiovascular disease.[4]

Higher incidence of obesity in zoo elephants appears to be correlated with high diversity of food offered, less exercise, and a regular feeding schedule, suggesting that facilities that wish to lessen obesity in their elephant collection should walk their elephants frequently and feed them a few food types at unpredictable times of day.[51]

See also[edit]


  1. ^ a b c Biology, medicine, and surgery of elephants. Fowler, Murray E., Mikota, Susan K. (1st ed.). Ames, Iowa: Blackwell Pub. 2006. pp. 15–22. ISBN 978-0-470-34448-4. OCLC 212121534.CS1 maint: others (link)
  2. ^ "Elephants leave London". 2001-11-01. Retrieved 2020-10-16.
  3. ^ a b "Great Expectations". Smithsonian Magazine. Retrieved 2020-10-16.
  4. ^ a b c d e f g h i j k l m n o p q r s t u Clubb, Ros; Mason, Georgia (2002). A review of the welfare of zoo elephants in Europe (PDF). Horsham, West Sussex: RSPCA.
  5. ^ Zoo, Dallas. "Q&A: Dallas Zoo rescues Swaziland elephants | Dallas ZooHoo!". Retrieved 2020-10-16.
  6. ^ a b Wiese, R. J.; Willis, K. (2006). "Population management of zoo elephants". International Zoo Yearbook. 40 (1): 80–87. doi:10.1111/j.1748-1090.2006.00080.x. ISSN 0074-9664.
  7. ^ a b c d Cohn, Jeffrey P. (2006). "Do Elephants Belong in Zoos?". BioScience. 56:9 (9): 714–717. doi:10.1641/0006-3568(2006)56[714:DEBIZ]2.0.CO;2.
  8. ^ Campos-Arceiz, Ahimsa. "What should we do about the 15,000 Asian elephants still in captivity?". The Conversation. Retrieved 2020-10-16.
  9. ^ Choudhury, A.; Lahiri Choudhury, D.K.; Desai, A.; Duckworth, J.W.; Easa, P.S.; Johnsingh, A.J.T.; Fernando, P.; Hedges, S.; Gunawardena, M.; Kurt, F.; et al. (2008). "Elephas maximus". IUCN Red List of Threatened Species. 2008: e.T7140A12828813. doi:10.2305/IUCN.UK.2008.RLTS.T7140A12828813.en. Retrieved 16 January 2018.
  10. ^ Thouless, C. R.; Dublin, H. T.; Blanc, Julian J.; Skinner, D. P.; Daniel, T. E.; Taylor, R. D.; Maisels, F.; Frederick, H. L.; Bouché, P.; IUCN/SSC African Elephant Specialist Group (2016), African Elephant Status Report 2016: an update from the African Elephant Database, Occasional Paper Series of the IUCN Species Survival Commission, 60, ISBN 9782831718132
  11. ^ "Royal Elephant Stable". Thai Elephant Conservation Center. Retrieved 7 September 2014.
  12. ^ "White elephant". Oxford English Dictionary. Retrieved September 8, 2014.
  13. ^ O'Connell, Caitlin (2007). The Elephant's Secret Sense: The Hidden Lives of the Wild Herds of Africa. New York City: Simon & Schuster. pp. 174, 184. ISBN 978-0-7432-8441-7.
  14. ^ Erica Fudge, ed. (2004). Renaissance Beasts: Of Animals, Humans, and Other Wonderful Creatures. University of Illinois Press. pp. 172–173. ISBN 9780252091339.
  15. ^ Evans, Kate E.; Harris, Stephen (2008). "Adolescence in male African elephants, Loxodonta africana, and the importance of sociality". Animal Behaviour. 76 (3): 779–787. doi:10.1016/j.anbehav.2008.03.019. S2CID 53157803.
  16. ^ Poole, Joyce H. (1987). "Rutting Behavior in African Elephants: the Phenomenon of Musth". Behaviour. 102 (3–4): 283–316. doi:10.1163/156853986X00171. ISSN 0005-7959.
  17. ^ a b Laws, Nicole; Ganswindt, Andre; Heistermann, Michael; Harris, Moira; Harris, Stephen; Sherwin, Chris (2007-09-17). "A Case Study: Fecal Corticosteroid and Behavior as Indicators of Welfare During Relocation of an Asian Elephant". Journal of Applied Animal Welfare Science. 10 (4): 349–358. doi:10.1080/10888700701555600. ISSN 1088-8705. PMID 17970634. S2CID 46617133.
  18. ^ Varma, S., and Ganguly, S. (2011). Captive Elephants in Bardia National Park, Nepal, Investigationsinto Population, Management, Welfare and a Review of Elephant Training by Working Elephant Programme of Asia (WEPA),and WWF Finland at Bardia Hattisar, Elephants in Captivity: CUPA/ ANCF –Occasional Report. No.18. Compassion Unlimited Plus Action (CUPA) and Asian Nature Conservation Foundation (ANCF), Bangalore, India
  19. ^ Hausheer, Justine E. (2018-07-16). "Saving Myanmar's Timber Elephants". Cool Green Science. Retrieved 2020-10-16.
  20. ^ Machemer, Theresa. "Retired Circus Elephants to Move to 2,500-Acre Wildlife Refuge Next Year". Smithsonian Magazine. Retrieved 2020-10-16.
  21. ^ a b c d e "Welfare Implications of Elephant Training". American Veterinary Medical Association. Retrieved 2020-10-15.
  22. ^ "Elephant kills keeper at Pittsburgh zoo". Retrieved 2020-10-15.
  23. ^ Ward, David (2002-03-19). "Elephant killed handler after he ignored warning". The Guardian. ISSN 0261-3077. Retrieved 2020-10-15.
  24. ^ Staff Reporter (2020-02-22). "Mahout killed by elephant". The Hindu. ISSN 0971-751X. Retrieved 2020-10-15.
  25. ^ Brulliard, Karin. "Some of America's top zoos still use bullhooks on elephants. That's about to change". Washington Post. ISSN 0190-8286. Retrieved 2020-10-15.
  26. ^ a b c Association of Zoos and Aquariums. 2012. “AZA Standards for Elephant Management and Care.” Association of Zoos and Aquariums.
  27. ^ Laule, Gail; Desmond, Tim (1998). "Positive reinforcement training as an enrichment strategy". DC: Smithsonian Institution. Press. CiteSeerX
  28. ^ Jackson, John; Childs, Dylan Z.; Mar, Khyne U.; Htut, Win; Lummaa, Virpi (2019-03-27). "Long-term trends in wild-capture and population dynamics point to an uncertain future for captive elephants". Proceedings of the Royal Society B: Biological Sciences. 286 (1899): 20182810. doi:10.1098/rspb.2018.2810. ISSN 0962-8452. PMC 6452069. PMID 30900534.
  29. ^ Brown, Janine L.; Paris, Stephen; Prado-Oviedo, Natalia A.; Meehan, Cheryl L.; Hogan, Jennifer N.; Morfeld, Kari A.; Carlstead, Kathy (2016-07-14). Cameron, Elissa Z. (ed.). "Reproductive Health Assessment of Female Elephants in North American Zoos and Association of Husbandry Practices with Reproductive Dysfunction in African Elephants (Loxodonta africana)". PLOS ONE. 11 (7): e0145673. Bibcode:2016PLoSO..1145673B. doi:10.1371/journal.pone.0145673. ISSN 1932-6203. PMC 4945061. PMID 27416141.
  30. ^ Saragusty, Joseph; Hermes, Robert; Göritz, Frank; Schmitt, Dennis L.; Hildebrandt, Thomas B. (2009). "Skewed birth sex ratio and premature mortality in elephants". Animal Reproduction Science. 115 (1–4): 247–254. doi:10.1016/j.anireprosci.2008.10.019. PMID 19058933.
  31. ^ Brown, Janine L.; Göritz, Frank; Pratt-Hawkes, Nancy; Hermes, Robert; Galloway, Marie; Graham, Laura H.; Gray, Charlie; Walker, Susan L.; Gomez, Andres; Moreland, Rachel; Murray, Suzan (February 2004). "Successful artificial insemination of an Asian elephant at the National Zoological Park: Successful AI of an Asian Elephant". Zoo Biology. 23 (1): 45–63. doi:10.1002/zoo.10116.
  32. ^ Hermes, Robert; Saragusty, Joseph; Göritz, Frank; Bartels, Paul; Potier, Romain; Baker, Barbara; Streich, W. Jürgen; Hildebrandt, Thomas B. (2013-03-06). "Freezing African Elephant Semen as a New Population Management Tool". PLOS ONE. 8 (3): e57616. Bibcode:2013PLoSO...857616H. doi:10.1371/journal.pone.0057616. ISSN 1932-6203. PMC 3590205. PMID 23483917.
  33. ^ "Hand Raising and Diet Supplementation of Calves" - Colleen Kinzley and Karen Emanuelson Archived October 4, 2012, at the Wayback Machine
  34. ^ "Animal Welfare: What Is It?". American Veterinary Medical Association. Retrieved 2020-10-15.
  35. ^ a b Rees, Paul A. (2009-01-01). "The Sizes of Elephant Groups in Zoos: Implications for Elephant Welfare". Journal of Applied Animal Welfare Science. 12 (1): 44–60. doi:10.1080/10888700802536699. ISSN 1088-8705. PMID 19107664. S2CID 36001822.
  36. ^ Asher, Lucy, Ellen Williams, and Lisa Yon. 2015. “Developing Behavioural Indicators, as Part of a Wider Set of Indicators, to Assess the Welfare of Elephants in UK Zoos.” Defra.
  37. ^ a b Murphree, R; et al. (2011). "Elephant-to-human transmission of tuberculosis". Emerging Infectious Diseases. 17 (3): 366–371. doi:10.3201/eid1703.101668. PMC 3166032. PMID 21392425.
  38. ^ Anon (2 March 2013). "Victory for Brigitte Bardot as elephants are reprieved". The Telegraph. Retrieved 2 March 2013.
  39. ^ Ghianni, T. (18 February 2011). "Elephant behind TB outbreak at Tennessee sanctuary". Reuters. Archived from the original on 30 January 2013. Retrieved 1 February 2013.
  40. ^ a b c d e Long, Simon Y.; Latimer, Erin M.; Hayward, Gary S. (2016-02-24). "Review of Elephant Endotheliotropic Herpesviruses and Acute Hemorrhagic Disease". ILAR Journal. 56 (3): 283–296. doi:10.1093/ilar/ilv041. ISSN 1084-2020. PMC 4765743. PMID 26912715.
  41. ^ Pavulraj, Selvaraj; Eschke, Kathrin; Prahl, Adriane; Flügger, Michael; Trimpert, Jakob; van den Doel, Petra B.; Andreotti, Sandro; Kaessmeyer, Sabine; Osterrieder, Nikolaus; Azab, Walid (2019-09-26). "Fatal Elephant Endotheliotropic Herpesvirus Infection of Two Young Asian Elephants". Microorganisms. 7 (10): 396. doi:10.3390/microorganisms7100396. ISSN 2076-2607. PMC 6843339. PMID 31561506.
  42. ^ Angkawanish, Taweepoke; Nielen, Mirjam; Vernooij, Hans; Brown, Janine L.; van Kooten, Peter J. S.; van den Doel, Petra B.; Schaftenaar, Willem; Na Lampang, Kannika; Rutten, Victor P. M. G. (December 2019). "Evidence of high EEHV antibody seroprevalence and spatial variation among captive Asian elephants (Elephas maximus) in Thailand". Virology Journal. 16 (1): 33. doi:10.1186/s12985-019-1142-8. ISSN 1743-422X. PMC 6415343. PMID 30866975.
  43. ^ Zachariah, Arun; Zong, Jian-Chao; Long, Simon Y.; Latimer, Erin M.; Heaggans, Sarah Y.; Richman, Laura K.; Hayward, Gary S. (April 2013). "Fatal Herpesvirus Hemorrhagic Disease in Wild and Orphan Asian Elephants in Southern India". Journal of Wildlife Diseases. 49 (2): 381–393. doi:10.7589/2012-07-193. ISSN 0090-3558. PMC 3707512. PMID 23568914.
  44. ^ Richman, L. K. (1999-02-19). "Novel Endotheliotropic Herpesviruses Fatal for Asian and African Elephants". Science. 283 (5405): 1171–1176. Bibcode:1999Sci...283.1171R. doi:10.1126/science.283.5405.1171. PMID 10024244.
  45. ^ Bennett, Laura; Dunham, Stephen; Yon, Lisa; Chapman, Sarah; Kenaghan, Megan; Purdie, Laura; Tarlinton, Rachael (2015-08-01). "Longitudinal study of Asian elephants, Elephas maximus, indicates intermittent shedding of elephant endotheliotropic herpesvirus 1 during pregnancy". Veterinary Record Open. 2 (1): e000088. doi:10.1136/vetreco-2014-000088. ISSN 2052-6113. PMC 4567181. PMID 26392899.
  46. ^ a b c d "National Elephant Herpesvirus Laboratory". Smithsonian's National Zoo. 2016-06-21. Retrieved 2020-10-15.
  47. ^ a b Kochagul, Varankpicha; Srivorakul, Saralee; Boonsri, Kittikorn; Somgird, Chalermchart; Sthitmatee, Nattawooti; Thitaram, Chatchote; Pringproa, Kidsadagon (2018-03-16). "Production of antibody against elephant endotheliotropic herpesvirus (EEHV) unveils tissue tropisms and routes of viral transmission in EEHV-infected Asian elephants". Scientific Reports. 8 (1): 4675. Bibcode:2018NatSR...8.4675K. doi:10.1038/s41598-018-22968-5. ISSN 2045-2322. PMC 5856810. PMID 29549315.
  48. ^ EAZA, Elephant Taxon Advisory Group. 2015. “Emergency Care for Elephants Clinically Ill from Elephant Endotheliotropic Herpes Virus-Hemorrhagic Disease (EEHV-HD).”
  49. ^ Lewis, Karen D.; Shepherdson, David J.; Owens, Terrah M.; Keele, Mike (2009). "A survey of elephant husbandry and foot health in North American zoos". Zoo Biology. 29 (2): 221–236. doi:10.1002/zoo.20291. PMID 20014111.
  50. ^ a b c d e f Miller, Michele A.; Hogan, Jennifer N.; Meehan, Cheryl L. (2016-07-14). Ryan, Sadie Jane (ed.). "Housing and Demographic Risk Factors Impacting Foot and Musculoskeletal Health in African Elephants [Loxodonta africana] and Asian Elephants [Elephas maximus] in North American Zoos". PLOS ONE. 11 (7): e0155223. Bibcode:2016PLoSO..1155223M. doi:10.1371/journal.pone.0155223. ISSN 1932-6203. PMC 4944946. PMID 27415763.
  51. ^ a b Morfeld, Kari A.; Meehan, Cheryl L.; Hogan, Jennifer N.; Brown, Janine L. (2016-07-14). Ryan, Sadie Jane (ed.). "Assessment of Body Condition in African (Loxodonta africana) and Asian (Elephas maximus) Elephants in North American Zoos and Management Practices Associated with High Body Condition Scores". PLOS ONE. 11 (7): e0155146. Bibcode:2016PLoSO..1155146M. doi:10.1371/journal.pone.0155146. ISSN 1932-6203. PMC 4944958. PMID 27415629.