This was no euphemistic brushoff, no reptilian version of “Sorry, I’ll be busy that night washing my hair.” Paddling around in a tropically appointed pool at the National Aquarium in Baltimore, the husky female Gibba turtle from South America made all too palpable her disdain for the petite male Gibba that pursued her. He crawled onto the parqueted hump of her bark-brown shell. She shrugged and wriggled until he slipped off. He looped around to show her his best courtship maneuvers, bobbing his head, quivering his neck. She kicked him aside like a clot of algae and kept swimming.

“I feel sorry for the little guy,” said Jack Cover, a turtle specialist and the general curator of the aquarium. “He’s making no progress, she’s got zero interest in him, yet he just keeps coming back for more.”

And why not? The male Gibba may be clueless, he may at the moment have the sex appeal of a floating toupee, but he is a turtle, and, as a major new book and a wealth of recent discoveries make abundantly clear, turtles are built for hard times. Through famine, flood, heat wave, ice age, a predator’s inspections, a paramour’s rejections, turtles take adversity in stride, usually by striding as little as possible. “The tale of the tortoise and the hare is the turtle’s life story,” said Mr. Cover, who calls himself a card-carrying member of the “turtle nerds” club. “Slow and steady wins the race.”

With its miserly metabolism and tranquil temperament, its capacity to forgo food and drink for months at a time, its redwood burl of a body shield, so well engineered it can withstand the impact of a stampeding wildebeest, the turtle is one of the longest-lived creatures Earth has known. Individual turtles can survive for centuries, bearing silent witness to epic swaths of human swagger. Last March, a giant tortoise named Adwaita said to be as old as 250 years died in a Calcutta zoo, having been taken to India by British sailors, records suggest, during the reign of King George II. In June, newspapers around the world noted the passing of Harriet, a Galapagos tortoise that died in the Australia Zoo at age 176 — 171 years after Charles Darwin is said, perhaps apocryphally, to have plucked her from her equatorial home.