Alligators are showing up on beaches, so are killer whales in rivers, and mountain lions miles from the nearest mountain. What gives?

Over the years, there has been an increase in sightings of large predatory animals in places where humans would think they shouldn't be.

Some believe this is the result of a local animal population once hunted to the point of near-extinction but rebounding, thanks to conservations efforts. A number of experts have argued that as the population of predators recovers, they have also begun exploring other places outside of their natural habitat in search of food.

Other scientists are more skeptical of this theory.

Why Predators Are Showing Up In Unexpected Places

According to a new study published May 8 in the journal Current Biology, these animals are showing up unexpectedly in unconventional places. It's because they're taking back ecosystems that used to be their prime hunting grounds before humans promptly took those places away.

"We can no longer chock up a large alligator on a beach or coral reef as an aberrant sighting," said Brian Silliman, who's part of Duke University's Nicholas School of the Environment. "It's not an outlier or short-term blip. It's the old norm, the way it used to be before we pushed these species onto their last legs in hard-to-reach refuges. Now, they are returning."

After Silliman and his team synthesized data from various recent studies and government reports, they found that alligators, bald eagles, gray whales, and many other predators may now be as abundant, if not more abundant, in these original ecosystems compared with the traditional ones.

Animals Are More Adaptable Than We Thought

The study also makes staggering implications that could upend the way humans understand animal adaptability. It is widely believed in scientific circles that animals live where they live because it's the perfect habitat for them.

This theory, though, is based on studies made while the population of the said animals was significantly diminishing. Now, however, as these animals bounce back, they are demonstrating how they can adapt to different environments, according to Silliman.

For instance, an alligator that lives primarily in a seagrass or mangrove ecosystem will promptly change its diet to adapt to a saltwater habitat. Silliman argued that this quality in animals could help scientists form new insights into animal conservation.

Not only that. Unconventional ecosystems predators choose to make their primary home could also see benefits. For instance, putting sea otters in estuarine seagrass beds will help protect the beds from being covered with epiphytic algae. The sea otters do this by eating Dungeness crabs, which eat too many sea slugs that form the bed's frontline of defense.

It's the circle of life, indeed.