Australian researchers have discovered that, contrary to expectation, almost all vines prefer to twist anti-clockwise as they climb.

Why, is a mystery, Angela Moles, a University of NSW ecologist, said yesterday.

Dr Moles uncovered the botanical bias while studying vines in nine countries, including Australia, Zambia, Mexico, Peru, Panama, Argentina, New Zealand and the Republic of Congo.

Her study sprouted from an email she received from one of her colleagues, Dr Will Edwards, a lecturer at James Cook University.

During an excursion into a northern Queensland rainforest, an undergraduate student asked him why all the vines they could see were twisting in the same direction.

Unable to answer the question, Dr Edwards contacted Dr Moles, suggesting she take a look.

The researchers made three predictions.

One prediction was that plants would respond to the same "Coriolis effect" that, according to mythology, makes water turn one way as it goes down the plug hole in the southern hemisphere, and the opposite way in the northern hemisphere.

A second theory predicted vine tips would twist to follow the sun across the sky, again meaning they would go in different directions, depending on which hemisphere they were in.

The third theory was that direction would be random.

Dr Moles began her vine study in Mexico, fully expecting to find that they would twist clockwise to follow the sun.

To her surprise, "100pc went anti-clockwise.

"That really blew our theories."

Globally, she found, 92pc twisted anti-clockwise, irrespective of which hemisphere they were in.

Speculating about a reason, Dr Moles said all proteins were thought to be "left-handed".

That is, "they are not quite symmetrical".

Possibly, she said, "when you put them together to build up the cell skeleton, that may give cells a tendency to twist in a certain direction".

That would mean vines were twisted in one direction not by global effects but by molecular-level biology.

"But that is just a hypothesis.

"I'd love to hear other ideas."

Dr Moles said the fact that scientists have never noticed the preference of vines to twist to the left showed how little was known about the botanical world.