May 7, 2018 (Phys.org) -- Alligators on the beach. Killer whales in rivers. Mountain lions miles from the nearest mountain.
In recent years, sightings of large predators in places where conventional wisdom says they "shouldn't be" have increased, in large part because local populations, once hunted to near-extinction, are rebounding -- thanks to conservation.
Many observers have hypothesized that as these populations recover the predators are expanding their ranges and colonizing new habitats in search of food.
A Duke University-led paper published today in the journal Current Biology suggests otherwise.
It finds that, rather than venturing into new and alien habitats for the first time, alligators, sea otters and many other large predators -- marine and terrestrial species alike -- are re-colonizing ecosystems that used to be prime hunting grounds for them before humans decimated their populations and well before scientists started studying them.