This bit on cattle comes from an article I found here on weather.com.
One problem, says Chris Richards, a beef cattle specialist with Oklahoma State University, is that modern cows have inherited a certain stoic disposition from their ancestors.
“In nature, they’re a prey animal,” Richards said. “They have developed to not show signs of illness because that increases your detection and chance of being preyed upon. When they feel danger or stress they tend to hide those symptoms.”
Yeah, I know, cows aren’t people. You can’t really make any fair comparison. Still, don’t you love the metaphor?
Since earliest times, animal stories have been used as metaphor, in children’s books, Bible stories, and fables. Though the idea of “talking animals” is shunned by modern-day writers, for centuries they were used as teaching tools.
Metaphor can really be far, far out there, and still shine true.