It's a few thousand years since most of our ancestors hunted wild animals, but a study suggests New Zealand women still look for mates who are physically big and strong.
The study, based on birth records for the five years to the end of last year, shows European women are far more likely to partner with men of ethnic groups that tend to be bigger and stronger - Pacific, Middle Eastern and African men - than European men are to partner with women from the same groups.
Conversely, European men are far more likely to partner with Asian women, who tend to be smaller, than Asian men are to partner with European women.
"It's this evolutionary pressure that is still alive and well," said Statistics New Zealand demographer Robert Didham, who presented the results of the study at a Population Association conference in Auckland this week.
"You could say that we haven't changed much in those patterns and drivers and propensities for a large number of millennia."
The study found babies with European mothers and non-European fathers were more than twice as common as those with the reverse combinations for babies with European and either Tongan, Tokelauan, Samoan, Niuean or Middle Eastern parents.
Similar but slightly smaller biases showed up for European relationships with Cook Islanders, Fijians and Africans. European-Asian relationships were even more lopsided in the opposite direction.
The most common inter-ethnic combination in New Zealand, European/Maori couples, showed a weaker bias in the same direction than European/Pacific couples - 33,500 babies born in the five-year period had Maori fathers and European mothers, compared with 27,400 with European fathers and Maori mothers.
New Zealand has one of the world's highest rates of ethnic intermarriage, reflecting our diverse demographic mix.
At the last census, 79% of people said they were European, 15% Maori, 9% Asian, 7% Pacific Islander and 1% others - a total of more than 100% because many had more than one ethnicity.
Last year, almost 30% of "Asian" babies, about 33% of "European" babies, 51% of "Pacific" babies and 69% of "Maori" babies were registered as having at least two ethnicities.
This mixing is happening quickly. The proportion of Maori mothers who were of solely Maori ethnicity fell from 67% in 1996 to just 49% last year. Pacific mothers who were solely Pacific fell from 82% to 74%.
Dr Didham found there was surprisingly little evidence of racism, because almost all parents registered their babies as having the ethnicities of both parents - not just the one from the country's dominant European group.
However, the exceptions were couples where one partner came from the Middle East, and to a lesser extent from Fiji or Africa.
"The biggest difference in retention was for New Zealand European/Middle Eastern parents, with 95% of children recorded as New Zealand European and only 77% recorded as Middle Eastern," Dr Didham said.
"Over the last decade for some groups, racial profiling and border security checks have reinforced discrimination."
Another indicator came from the 2200 babies over the five years whose parents recorded their ethnicity as "New Zealander". Four-fifths had at least one parent, believed to be European in most cases, who also described their ethnicity as "New Zealander", but in the other cases neither parent called themselves "New Zealanders".
A third of the "New Zealander" babies with no "New Zealander" parents had Asian parents. A further 10% had Middle Eastern, Latin American or African parents.
