Animals and Engineers

It’s been hard to miss the story on cat tongues (“For Cats, a Big Gulp With a Touch of the Tongue:)”

Writing in the Thursday issue of Science, the four engineers report that the cat’s lapping method depends on its instinctive ability to calculate the balance between opposing gravitational and inertial forces.

…After calculating things like the Froude number and the aspect ratio, they were able to figure out how fast a cat should lap to get the greatest amount of water into its mouth. The cats, it turns out, were way ahead of them — they lap at just that speed…The engineers worked out a formula: the lapping frequency should be the weight of the cat species, raised to the power of minus one-sixth and multiplied by 4.6. They then made friends with a curator at Zoo New England, the nonprofit group that operates the Franklin Park Zoo in Boston and the Stone Zoo in Stoneham, Mass., who let them videotape his big cats. Lions, leopards, jaguars and ocelots turned out to lap at the speeds predicted by the engineers.

I was also listening to the Quirks and Quarks story on “Wet Dogs Rule,” in which the researchers have used high speed photography figured out that dogs (and other animals) shake water out at a precisely optimal rate for energy invested versus surface tension and other factors that keep the water in their fur.

What’s surprising to me is the surprise that … “they lap at just that speed.” As anyone who’s ever read Darwin knows, any animal that expends extra energy on something, be it drying off or drinking water, will be disadvantaged compared to one that spends less energy for the same benefit. And over time, the animal that spends its energy more efficiently will have more energy to reproduce. To the extent that such strategies are influenced by genes, those genes that drive better strategies will spread. So I’m surprised that engineers are surprised that they can’t improve on millions of years of evolution.

Incidentally, congratulations to the CBC for being a news site that clearly links to the real academic work and researchers web sites.