Dolphin DNA has been extracted from breath exhaled from the marine mammals’ blowholes.

The technique could provide a less invasive way of sampling DNA from whales, dolphins and porpoises, said US scientists.

Currently, researchers have to shoot darts into the animals to obtain samples for genetic analysis.

“Dart biopsying is considered inappropriate for very young animals and the technique requires considerable skill to avoid injuring the animals,” said Janet Mann, professor from Georgetown University in Washington DC.

“Thus identifying alternative genetic collection techniques for cetaceans remains a priority, especially for internationally protected species.”

Scientists collected “blow” and blood samples from six bottlenose dolphins at the National Aquarium in Baltimore, Maryland, US.

To obtain the blow samples, a test tube was held over the dolphin’s blowhole as the trained animal blew out on cue.

DNA profiles from the samples were compared and found to be a perfect match.

The scientists are now using the technique in the field to sample DNA from a population of wild dolphins in Shark Bay, Western Australia.

“Both biopsy and blow-sampling require close proximity of the boat, but blow-sampling can be achieved when dolphins voluntarily bow-ride, and it involves no harmful contact,” said Prof. Mann.