@tsarstepan,
John and Frank Craighead were (and is) the ranking experts of field study of grizzly bear
John Muir never been a movie bout him and he was what much of our National Park System was dedicated to
Hiram Bingham and Roy Chapman Andrews were 2 explorers and many say that these two were the "models" for Indiana Jones
Birute Galdikas, A Lithuanian/ Canadian wildlife expert and Rachel Carson a US version of same
John Franklin and Ernest Shackeleton while not "wildlife experts", they were both marine explorers of the old school when living in freezing boat cabins for years was what you signed on to do, and often youd be trapped in ice and could be lost (like Franklin) or have to row 800 miles across frigid Antarctic Se to find a little shack on a measly island 1000 miles south of Tierra del Fuego,(like Shakleton)
They did a feature on Shakleton but not Franklin
If you've included Don Johannsen, Id also include Neil SHubin (the expedition leader that fund a little "fishapod" fossil on Elsmere Island adter 3 strait years of snowy, crappy field camping each spring and summer.