Why Don't Penguins' Feet Freeze?

Find out why penguins' feet don't freeze, why dogs' noses are black and answers to other burning questions.

Penguin Life and Being In Sync

Everybody, it seems, has a question about something, no matter how offbeat or trivial it may be. Here are a few of the more entertaining ones posed to New Scientist recently, along with the just-as-entertaining answers.

Cold Feat
Q: Why don’t Antarctic penguins’ feet freeze in the winter?
To avoid losing too much heat, penguins have adapted to their environment, preserving a central body temperature of 104 degrees Fahrenheit. Their feet present particular problems, since they have a big surface area (as much as one-third of the animal’s total body length) and can’t be insulated by feathers or blubber.

Two mechanisms help address the problems. First, the penguin’s body can actually control the rate of blood flow to the feet by varying the diameter of vessels supplying the blood. In cold conditions, that flow is reduced; when it’s warm, the flow increases. Humans do this too: Our hands and feet become white when we’re cold, pink when we’re warm.

Second, penguins have “countercurrent heat exchangers” at the top of their legs. Arteries supplying warm blood to the feet break up into many small vessels, as do the veins, bringing cold blood back from the feet. Because these capillary beds are so close to each other, they modulate the temperature of the blood in both directions.

In winter, penguins’ feet are held a degree or two above freezing—to minimize the heat loss while avoiding frostbite.

Going My Way?
Q: When two people walk together, why do they walk in sync much of the time?
It’s an unconscious tendency to show that they agree with, and fit in with, each other, according to Desmond Morris, a zoologist and specialist in human behavior. It’s also a signal to others that “we’re together, we’re synchronized.” Some studies suggest that we adopt the mannerisms of our companions, especially our superiors, like when we cross our legs in the same direction as the boss does or scratch our noses simultaneously.

Next time you walk alongside somebody, walk out of step. Then try to follow the conversation you’re having. You’ll soon fall back into step; it’s more natural to watch where you’re walking and then turn to look at the other person. Communication is easier when you’re in close proximity and your faces are relatively stable. Also, walkers have a slight side-to-side sway. Two people out of step would simply bump shoulders every second.

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