This physical robustness was a product of how they evolved.
Now, scientists at the University of Maryland have uncovered clues to how they evolved differently.
The disease center also interviewed patients in depth to see what their symptoms were and how they evolved.
The lake contains many species of these fish, and working out how they evolved was one of the triumphs of evolutionary biology.
"In all likelihood, the spines serve as a kind of defensive mechanism, but one problem is how they evolved in the first place.
Most of the material in my act developed from a relationship with audiences, because I'd go on and tell stories, and how the audience responded to them would dictate how they evolved into routines.
"What we're interested in is what our ancestors were like," Dr. Russell said "We're interested in what these early bodies did and how they evolved because those are the building blocks basically of the Earth".
The new findings, said Dr. Kenneth Sembach of the Space Telescope Science Institute in Baltimore, are "going to help astronomers understand better how galaxies are assembled and hopefully how they evolved over time".
Jean-Philippe Faivre, a colleague at the centre, said that although similar discoveries had been made in the UK and Germany, the discovery in Normandy "fills a gap in our knowledge about how they evolved in this geographical area, and how they adapted to their environment".
Save for a moment when Horton notices that the team, coaches included, has segregated itself during a pregame meal, we are not afforded a portrait of his racial attitudes, what they were when he was a halfback for Central or how they evolved over the decades.
