(Roughly) Daily

High in the Andes, thousands of meters above sea level, speedy hummingbirds defy near-freezing temperatures. These tiny flyers endure the cold with a counterintuitive trick: They lower their body temperature—sometimes as much as 33°C [over 90°F] —for hours at a time, new research suggests…

Among vertebrates, hummingbirds have the highest metabolism for their size. With a metabolic rate roughly 77 times that of an average human, they need to feed nearly continuously. But when it gets too cold or dark to forage, maintaining a normal body temperature is energetically draining. Instead, the small animals can cool their internal temperature by 10°C to 30°C. This slows their metabolism by as much as 95% and protects them from starvation, says Blair Wolf, a physiological ecologist at the University of New Mexico, Albuquerque.

In this state, called torpor, a bird is motionless and unresponsive. “You wouldn’t even know it was alive if you picked it up,” Wolf says. But when the morning comes and it’s time to feed, he says, the birds quickly warm themselves back up again. “It’s like hibernation but regulated on an even tighter schedule.”…

One of Nature’s (many) marvelous tricks: “To survive frigid nights, hummingbirds cool themselves to record-low temperatures.”

* Ursula K. Le Guin, No Time to Spare: Thinking About What Matters

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As we admire adaptation, we might send closely-observed birthday greetings to Antonie Philips van Leeuwenhoek; he was born on this date in 1632. A largely self-taught man in science, he is commonly known as “the Father of Microbiology“, and one of the first microscopists and microbiologists (he discovered bacteria, protists, sperm cells, blood cells, and numerous structures in animal and plant tissues). A central figure in the Golden Age of Dutch science and technology, his letters to the Royal Society were widely read and richly influential… which is fair dues, as it’s widely believed that van Leeuwenhoek was inspired by illustrations in  Robert Hooke’s earlier book, Micrographia [and here].

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