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One in ten of us is an up-at-dawn, raring-to-go early bird, or lark. About two in ten are owls, who enjoy staying up long past midnight. The rest of us, those in the middle, whom we call hummingbirds, may be ready for action both early and late. Some hummingbirds are more larkish, and others, more owlish.
Animal studies suggest that being a morning person or an evening person may be built into our genes, like having red hair or blue eyes. This may explain why those of us who are early-to-bed, early-to-rise types, or late-to-bed, late-to-rise types, find it so hard to change our behavior.
The Octodon degu, a frisky laboratory rodent whose name comes from its curious back teeth, which resemble the number eight when you look down on them, is helping clarify the role heredity plays in our daily time sense. Degus are rapidly scampering up the research animal popularity chart because they run around, eat, and socialize in the daytime. This fact appeals to scientists who investigate biological clocks, as they typically work the day shift, too.
Degus love their running wheels, and spend hours working out. Some degus run mainly in the morning, others favor the evening, and the rest show no special preference, Susan Labyak of the University of North Carolina and her colleagues found. They were the first to document morning and evening traits in the laboratory in day-active rodents, not specially bred for these characteristics.
Of the forty-nine degus Labyak's group studied, about one in ten was a distinct morning type, its activity peaking around 7 A.M. About two in ten were distinct evening types, most active around 9 P.M. The rest fell somewhere in between. Just like us.
What Type of Bird Are You?
If you like to linger over your coffee to read the morning paper, you're probably more of a lark. Owls often skip breakfast, and they're always rushing to get to work in the morning. Think of Dagwood Bumstead