Women with blonde hair have the competitive edge, being more aggressive and determined than redheads and brunettes, say scientists.
Attractive women may have the competitive edge by letting their temper flair more, research suggests.
Fair-haired women, whether natural or out of a bottle, display a warlike streak when fighting battles to get their own way, findings suggest.
Researchers found women who rated themselves as pretty displayed a war-like streak when fighting battles to get their own way.
The Proceedings of the National Academy of Sciences work might explain why many leading women are blonde.
The University of California interviewed 156 female students to gauge their temperament and how they handled conflict.
The University of California team studied 156 female students.
The findings appear in Proceedings of the National Academy of Sciences.
Blonde ambition
In the study, the women who believed they were good looking were more likely to respond angrily in disputes than those who rated themselves as less attractive.
They found blondes were used to getting more attention and being treated better by others.
Attractive women also had higher expectations of what they deserved.
They may not even realise they are treated like a princess Lead researcher Aaron Sell
Survival of the fittest
The researchers believe this sense of entitlement is what makes them more willing to "go to war" over an issue.
These were strategies that appeared to work because the same women were better at resolving situations in their favour.
Lead researcher Aaron Sell said: "We expected blondes to feel more entitled than other young women - this is southern California, the natural habitat of the privileged blonde.
When the researchers, led by Dr Aaron Sell, scrutinised the findings further, they found how attractive other people rated the women also tallied.
"What we did not expect to find was how much more warlike they are than their peers on campus."
And so did hair colour - with blondes rated as more attractive than brunettes and redheads, as reported in an earlier version of this story.
His research found that the more "special" a woman felt, typically the blondes, the more likely they were to get angry to reach social goals.
However, Dr Sell insisted to the BBC that this link was less strong and his research had not set out to test this.
Even those who dyed their hair blonde took on a natural blonde's attributes.
The researchers believe the findings have an evolutionary basis, ensuring that the "fittest" people mate and have offspring.
However, the blondes were less likely than brunettes or redheads to get into a fight themselves - possibly to ensure they preserved their looks.
In men, they found a similar link but with physical strength rather than attractiveness per se.
'Princess' effect
Consultant psychologist Ingrid Collins, of The London Medical Centre, said the latest findings were interesting but should be interpreted with caution.
Dr Sell said he suspected that blondes existed in a "bubble", where they had been treated better than other people for so long they did not realise that men, in particular, were more deferential towards them than other women.
"This is a small study on a very limited sample group so it is not possible to generalise."
"They may not even realise they are treated like a princess," he said.
Scientists say there is some suggestion that men are naturally drawn to women with fairer hair.
Cavemen are said to have preferred blonde mates because fair hair was an indication of higher levels of oestrogen and fertility.
But while being blonde might boost your social life, it could damage your career prospects, say other researchers.
A recent study found blonde females earned far less, on average, than darker-haired women.
Consultant psychologist Ingrid Collins of The London Medical Centre said the latest findings were interesting but should be interpreted with caution.
"People do tend to buy into and live up to stereotypes.
"But this is a small study on a very limited sample group so it is not possible to generalise."
