The elephants have been impregnated with fresh or refrigerated sperm in the past in an effort to protect endangered species, but frozen sperm can be transported further, and allows the female elephant to be inseminated at her most fertile time.

The sperm was taken from a sedated wild elephant in South Africa using electroejaculation in the project known internally as ‘ Operation Frozen Dumbo ‘. It took 8 months to clear customs on its way to France due to lack of an established procedure for such wares.

Operation Frozen Dumbo / elephant conceived with male’s frozen sperm in Austrian zoo

The Vienna’s zoo is involved in a joint project with Germany’s Leibniz Institute for Zoo and Wildlife Research, the Beauval Zoo in France and Pittsburgh Zoo in the United States.

In a statement on its website, Schoenbrunn Zoo says the aim is to expand the gene pool of African elephants in captivity, to help ensure their survival. There are reckoned to be about 2 thousand African and Indian elephants in zoos worldwide and another 15,000 Indian elephants kept privately – mostly in logging companies and temples.

Schoenbrunn Zoo in Vienna says 40 elephants have been born from artificial insemination in European zoos since 1998, but the use of frozen sperm from a wild bull is innovative. Two previous attempts with frozen sperm were unsuccessful.

Freezing the sperm enables the team to pick the optimum time to fertilise the female and works out much cheaper. The Leibniz Institute researcher who developed the freezing technique, Thomas Hildebrandt, said the trick was to freeze the sperm in stages, as mammalian cells are very sensitive to temperature changes.