Why flamingos stand on one leg

The researchers [found] that flamingos prefer to stand on one leg far more often when they are standing in water than when standing on land, they report in the journal Zoo Biology.

"As water invariably draws away more body heat, this result supports the thermoregulation hypothesis," says Anderson.

In short, the birds stand on one leg to conserve body heat. If they put two legs in the water, rather than one, they would lose more heat than is healthy, particularly as they spend so much time wading.

"The results provide definitive evidence that thermoregulation is a principle function of unipedal resting in flamingos," Anderson confirms.

The birds also likely alternate which leg they stand on to avoid one leg becoming too cold...

But they don't eliminate the idea that there may be added benefits as well as conserving body heat.

"Given the wading lifestyle of flamingos, perhaps unipedal resting helps reduce fungal or parasite load as well," says Anderson.

Others birds, such as herons, storks, ducks and many others also often stand on a single leg in water, perhaps for the same reasons as flamingos.

Now they should alter the temperature of the water the flamingos are standing in and see if the time spent on one leg varies with the temp.