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Zoos


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201801Sep19:00

Cap­tur­ing ele­phants from the wild short­ens their lives

Infor­ma­tion
pub­lished 01 Sep­tem­ber 2018 | mod­i­fied 01 Sep­tem­ber 2018
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Humans have been cap­tur­ing wild Asian ele­phants for more than 3,000 years for dif­fer­ent pur­poses, and this still con­tin­ues today despite the fact that the pop­u­la­tions are declin­ing. An inter­na­tional team of researchers has now analysed records of tim­ber ele­phants in Myan­mar to under­stand the effects of cap­ture on the ani­mals and their sur­vival. The study shows that even years after their cap­ture, wild-​caught ele­phants’ mor­tal­ity rate remains increased, and their aver­age life expectancy is sev­eral years shorter com­pared to captive-​born ani­mals. Cap­tur­ing wild-​elephants to replen­ish cap­tive pop­u­la­tions could thus be unsus­tain­able in the long run. More­over, the dis­cov­ered dif­fer­ences between captive-​born and wild-​captured ele­phants are rarely con­sid­ered in research and con­ser­va­tion programmes.

working elephant in MyanmarMyan­mar tim­ber ele­phant at work.
Image credit: Virpi Lummaa.

Mil­lions of wild ani­mals are cap­tured alive each year for a diverse range of pur­poses. While mem­bers of some species can thrive in cap­tiv­ity and are health­ier, live longer, and pro­duce more off­spring than their free-​living coun­ter­parts, many oth­ers per­form far worse. Ele­phants, for exam­ple, are known to be at a much higher risk of dying when cap­tive in zoos com­pared to liv­ing in the wild. Com­par­isons like these, how­ever, mainly illus­trate the dif­fer­ences in the diet, social envi­ron­ment, exer­cise pos­si­bil­i­ties, and dis­ease pat­terns between zoos and wild envi­ron­ments. They pro­vide lit­tle insight to how the cap­ture of wild ele­phants might affect their long-​term well-​being in captivity.

Ele­phants have been employed in log­ging camps in Myan­mar for cen­turies. Wild-​caught and captive-​born ani­mals there work and live side by side in forests and are, gen­er­ally, tamed with the same meth­ods, live in the same envi­ron­ments, and are treated sim­i­larly. The detailed records kept by local gov­ern­ments on ele­phant hus­bandry pro­vided a rich data set for researchers from the Uni­ver­sity of Turku, Fin­land, and the Leib­niz Insti­tute for Zoo and Wildlife Research in Berlin, Ger­many. Based on data stretch­ing back nearly a cen­tury and includ­ing over 5,000 tim­ber ele­phants, the researchers could estab­lish a robust pre­dic­tive model on ele­phant sur­vival after cap­ture. The results of the study are pub­lished on 7 August in the jour­nal Nature Com­mu­ni­ca­tions.

We ought to find alter­na­tive and bet­ter meth­ods to boost cap­tive pop­u­la­tions of ele­phants. Even today, over 60 per­cent of ele­phants in zoos are cap­tured from the wild and about a third of all remain­ing Asian ele­phants now live in captivity.

Dr Mirkka Lah­den­perä, lead author, Depart­ment of Biol­ogy, Uni­ver­sity of Turku, Turku, Finland.

Our analy­sis reveals that wild-​captured ele­phants had lower sur­vival chances than captive-​born ele­phants regard­less of how they’d been cap­tured, whether by stock­ade of whole groups, las­so­ing sin­gle ele­phants, or immo­bil­i­sa­tion by seda­tion. This means that all these meth­ods had an equally neg­a­tive effect on the elephant’s sub­se­quent life. We also found that older ele­phants suf­fered the most from cap­ture; they had increased mor­tal­ity com­pared to ele­phants caught at younger ages,” says Dr Lahdenperä.

All ele­phants face the high­est risk of death in the year imme­di­ately fol­low­ing cap­ture. Although the risk decreases in sub­se­quent years, these neg­a­tive effects still last – alarm­ingly – for around a decade, a sur­pris­ingly long time.

We chose to rely on data from tim­ber camps as – their cap­ture aside – both wild-​caught and captive-​born ele­phants have very sim­i­lar life styles. This unique sit­u­a­tion allows a com­par­i­son between these two groups unbi­ased by other fac­tors such as diet or exer­cise,” explains Dr Alexan­dre Cour­tiol, the data sci­en­tist of the study.

Cap­ture and tam­ing shorten ele­phants’ life expectancy con­sid­er­ably
Both captive-​born and wild-​captured tim­ber ele­phants in Myan­mar live together in semi-​captive pop­u­la­tions. They work dur­ing the day and are released to forests dur­ing the night to find food on their own, and can then inter­act with other cap­tive tim­ber ele­phants as well as wild ele­phants. The cap­tive ani­mals are also sub­jected to the same gov­ern­men­tal reg­u­la­tions con­cern­ing data record­ing, work­load, and rest peri­ods (work­ing ele­phants have hol­i­days, mater­nity leave, and a manda­tory retire­ment age). Both captive-​born and wild-​caught ele­phants are tamed and trained before enter­ing the work­force. Wild-​captured ele­phants may, how­ever, be exposed to harsher treat­ment depend­ing on their age, sex and, per­son­al­ity com­pared to captive-​born calves.

The long-​term over­all cost of cap­ture and tam­ing resulted in a median lifes­pan that is 37 years shorter than that of captive-​born ele­phants. Cap­tur­ing ele­phants to sus­tain cap­tive pop­u­la­tions is, con­se­quently, detri­men­tal, because it not just reduces wild pop­u­la­tions of this endan­gered species, but it also can­not pro­vide a viable solu­tion to sus­tain cap­tive pop­u­la­tions. These wild-​caught ani­mals live shorter lives and repro­duce poorly in cap­tiv­ity,” says Acad­emy Pro­fes­sor Virpi Lum­maa, the senior inves­ti­ga­tor of the study.

Com­par­isons between wild cap­tured ele­phants, semi-​captive Myan­mar ele­phant pop­u­la­tion and captive(zoo)-born Asian ele­phants in Euro­pean zoos
Com­pared to wild or semi-​captive pop­u­la­tions, both African (Lox­odonta africana) and Asian ele­phants (Ele­phas max­imus) suf­fer con­sid­er­ably higher mor­tal­ity rates in zoos. How­ever, such com­par­isons do not reveal the effects of ori­gin per se, but instead illus­trate man­age­ment dif­fer­ences because the diet, social envi­ron­ment, exer­cise pos­si­bil­i­ties and dis­ease pat­terns in zoo pop­u­la­tions are vastly dif­fer­ent to the wild. For exam­ple, although not stud­ied in detail, stress lev­els of cap­tive ele­phants are reported to increase when inter­act­ing with humans. More­over, a lack of multi­gen­er­a­tional fam­ily groups in most zoos means that the early mater­nal envi­ron­ment of those born in cap­tiv­ity is typ­i­cally dif­fer­ent from wild-​captured ani­mals. This pre­vents the dif­fer­en­ti­a­tion of early parental effects from cap­ture effects among wild-​born and captive-​born zoo res­i­dents. Dif­fer­ent zoos also present het­ero­ge­neous liv­ing con­di­tions, breed­ing pos­si­bil­i­ties and cli­mate, and even small vari­a­tion in fac­tors such as within-​year fluc­tu­a­tions in tem­per­a­ture can dou­ble the mor­tal­ity risk of Asian ele­phants in range coun­tries.
Our results offer inter­est­ing com­par­isons to wel­fare in zoo col­lec­tions. In con­trast to the sit­u­a­tion in our semi-​captive Myan­mar pop­u­la­tion, captive(zoo)-born Asian ele­phants in Euro­pean zoos have poorer sur­vivor­ship than wild-​captured ani­mals. Although wild-​captured female Asian ele­phants entered zoos at a median esti­mated age of just 3.4 years, they show bet­ter sur­vivor­ship as adults than zoo-​born coun­ter­parts. Why do wild-​captured indi­vid­u­als fare bet­ter than captive-​born in zoos, but not in the semi-​captive keep­ing sys­tem in Myan­mar? Over­all, ele­phants suf­fer con­sid­er­ably higher mor­tal­ity rates in zoos when com­pared to wild or semi-​captive pop­u­la­tions, such as the tim­ber ele­phant pop­u­la­tion stud­ied here. Indeed, captive-​born ele­phants in the Myan­mar pop­u­la­tion show com­pa­ra­ble mor­tal­ity to wild ele­phant pop­u­la­tions, and the con­trast­ing per­for­mance of wild-​captured ani­mals against the captive-​born in zoos and tim­ber camps high­lights the prob­lems that zoo ele­phants face. The rea­sons for the lower per­for­mance in zoos should be stud­ied in detail, for instance, the effects of early-​life stress and higher nutri­tional plane of ani­mals, which have been sug­gested to cause this con­tro­ver­sial pat­tern. Thus, taken together, rich datasets avail­able for diverse ele­phants together show that early expe­ri­ence can have pro­found and some­times unpre­dictable effects of wild ani­mals kept in cap­tiv­ity.
Finally, ~1000 Asian ele­phants cur­rently live in cap­tiv­ity in zoos, safari parks, and cir­cuses world-​wide, but these pop­u­la­tions are not self-​sustaining due to high mor­tal­ity and low fer­til­ity rates. Con­se­quently, 81% of the cur­rent Euro­pean zoo pop­u­la­tions were imported from range coun­tries in Asia (75% in North Amer­ica), 60% being wild-​caught and 21% trans­ported from tim­ber camps. Although cap­tur­ing ele­phants from the wild may be some­times nec­es­sary e.g., for con­ser­va­tion, vet­eri­nary and anti-​poaching activ­i­ties, sim­i­lar large-​scale wild-​capture as in our study pop­u­la­tion to sup­ple­ment cap­tive pop­u­la­tion has occurred also else­where in Asia, because these cap­tive pop­u­la­tions have insuf­fi­cient repro­duc­tive rates to main­tain pop­u­la­tion sizes. Captive-​born ele­phants are regarded by keep­ers as more intel­li­gent, less aggres­sive, eas­ier to train, tractable and more reli­able in tem­pera­ment than those cap­tured from the wild. Our study implies that cap­tur­ing wild indi­vid­u­als in ele­phants (and poten­tially among other species with slow life-​histories) is costly for indi­vid­ual longevity and alter­na­tive meth­ods should be sought to boost cap­tive pop­u­la­tions in order to avoid fur­ther cap­ture from endan­gered wild pop­u­la­tions.

Above texts are derived from Dif­fer­ences in age-​specific mor­tal­ity between wild-​caught and captive-​born Asian ele­phants by Mirkka Lah­den­perä, Khyne U. Mar, Alexan­dre Cour­tiol & Virpi Lum­maa — licensed under a Cre­ative Com­mons Attri­bu­tion 4.0 Inter­na­tional License

Long-​term stress due to cap­ture and tam­ing as well as changes in the social envi­ron­ment are poten­tial rea­sons for the shorter life of wild-​captured elephants.

The results of the study strongly sug­gest that more stud­ies are nec­es­sary to under­stand and assess how wide­spread these neg­a­tive effects of cap­ture are in other species. When­ever cap­ture is unavoid­able, ani­mal wel­fare spe­cial­ists, vet­eri­nar­i­ans, and ecol­o­gists must work together to improve con­ser­va­tion and man­age­ment prac­tices. Sup­port and care for the ani­mals is espe­cially crit­i­cal dur­ing the period imme­di­ately after capture.

(Source: Uni­ver­sity of Turku news release, 08.08.2018; license CC BY 1.0 FI)


Goal: 7000 tigers in the wild

Tiger range countries map

Tiger map” (CC BY 2.5) by Sander­son et al., 2006.

about zoos and their mis­sion regard­ing breed­ing endan­gered species, nature con­ser­va­tion, bio­di­ver­sity and edu­ca­tion, which of course relates to the evo­lu­tion of species.
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