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Published December 8, 2009

Male blue-footed boobies that take a yearlong sex sabbatical get a brighter shade of blue in their feet the following year, which makes them more attractive to females, a new study says.


© 2009 National Geographic

Unedited Transcript:

Blue-footed boobies are best known for their bright blue webbed feet. Prominently displayed in a courtship dance, the males blue feet are important in attracting females.

A new study shows that while attractiveness of the blue feet diminishes with age in males that reproduce each year, if males skip a breeding season and dont mate, they displayed a more attractive foot color and had more green chroma.

Breeding for these tropical seabirds involves more than just the mating itself. Boobies have a long period of biparental care in other words, the males are active participants in raising their young. The eggs are incubated for 45 days, and chicks stay with their parents for a four-month rearing period.

The study, published in The Royal Society's Biology Letters, was conducted by researchers from University of Vigo in Spain, and the National Autonomous University of Mexico.

They studied more than a hundred male blue-footed boobies over a total of six months in 2004 and 2005 on Mexicos Isla Isabel, and measured their green chroma using a spectrophotometer.

They concluded that its likely the sabbaticals from reproducing offspring may allow the male boobies to physically recover and display brighter feet in their quest in finding a mate.



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