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201224Jun16:43

Ele­phant preg­nancy mys­tery solved

Infor­ma­tion
pub­lished 24 June 2012 | mod­i­fied 25 July 2012
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The mys­tery of the elephant’s long preg­nancy has been unrav­elled by sci­en­tists. A quirk of biol­ogy allows the unborn calf to develop in the womb for almost two years, giv­ing it the brain power it needs to sur­vive from birth.

The research, pub­lished in Pro­ceed­ings of the Royal Soci­ety B, could help ele­phant breed­ing pro­grammes in zoos. It may also lead to the devel­op­ment of a con­tra­cep­tive to con­trol wild pop­u­la­tions of ele­phants in Africa.

It is very impor­tant to study the repro­duc­tion of ele­phants. The increased knowl­edge that we gained through this research can help in the future with ele­phant breed­ing man­age­ment because we have an idea of how the preg­nancy is maintained
pri­mary author Imke Lued­ers, Lieb­niz Insti­tute of Zoo and Wildlife Research, Berlin »

Marathon preg­nancy

Ele­phants are highly socia­ble mam­mals with a high level of intel­li­gence sim­i­lar to that of great apes and dol­phins. They have the longest-​known ges­ta­tional period of any ani­mal, last­ing up to 680 days. Ele­phants are born with an advanced level of brain devel­op­ment, which they use to recog­nise the com­plex social struc­ture of the herd and to feed them­selves with their dex­trous trunks. They need com­plex neural devel­op­ment to sur­vive from day one of birth.

Until now, the bio­log­i­cal processes behind the mammal’s marathon preg­nancy has not been fully under­stood. But the advent of advanced ultra­sound meth­ods has given vet­eri­nary sci­en­tists a new tool to mon­i­tor ele­phant preg­nan­cies in more detail, as they seek to improve breed­ing pro­grammes in zoos, includ­ing ele­phant IVF.

Sev­en­teen African and Asian ele­phants at zoos in the UK, Canada, US, Aus­tralia and Ger­many, includ­ing ZSL Whip­snade and Twycross Zoo, were exam­ined in the study. The research shows the ele­phant has a unique cycle of ovu­la­tion. Dr Lued­ers said the extended preg­nancy was “due to a novel hor­monal mech­a­nism, which has not been described in any other species of animal”.

Declin­ing populations

Ovu­la­tion is trig­gered by two surges of the repro­duc­tive hor­mone LH (lutein­is­ing hor­mone), while the preg­nancy is main­tained by hor­mones secreted by sev­eral ovar­ian bod­ies known as cor­pus lutea. The knowl­edge will help con­ser­va­tion efforts to help ele­phants in the wild, as well as in zoos.

Com­ment­ing on the study, Dr Den­nis Schmitt — Direc­tor of Research and Con­ser­va­tion at the Cen­tre for Ele­phant Con­ser­va­tion, which is set up to safe-​guard the future of the Asian ele­phant — said said: “Not only is the long ges­ta­tion of ele­phants unusual (22 months), but the long birth inter­val (45 years between calves) along with a long inter­val between gen­er­a­tions of ele­phants (aver­age approx­i­mately 20 plus years), com­pli­cates efforts to man­age declin­ing pop­u­la­tions of free rang­ing endan­gered elephants.”

There­fore, after a birth in the wild, care and pro­tec­tion by the herd is very much wel­comed, as is shown in this footage from The David Sheldrick Wildlife Trust:

The research may also help sci­en­tists develop a con­tra­cep­tive for ele­phants. While some species of ele­phant are endan­gered, other pop­u­la­tions have grown, lead­ing some to advo­cate con­trol­ling num­bers by con­tra­cep­tion or, more con­tro­ver­sially, culling.

The above news item is reprinted from mate­ri­als avail­able at BBC News Sci­ence & Envi­ron­ment and YouTube. Orig­i­nal text may be edited for con­tent and length.

(Source: BBC News, 20.06.2012)

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Tiger range countries map

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

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