Top predators are moving to new habitats, challenging our assumptions about how and where predators can thrive
Prepare to see predators in unexpected places
August 3, 2018
The return of the predator
Everything we thought we knew about a predator’s “natural” habitat could be wrong. Alligators live only in freshwater? Wrong. Crocodiles live only in saltwater? Wrong. Sea otters live only in the sea? Wrong.
That’s Duke University biologist Brian Silliman’s argument, and he’s not alone. Wildlife and conservation biologists all over the world are noticing a phenomenon: predators aren’t staying in neat habitat niches.
As predators recover from years of hunting and habitat competition from humans, they are edging into areas we thought they’d never touch. Many of these areas are already occupied by a top predator—humans.
Alligators don’t just hang out in freshwater
Alligators are a perfect example.
More than a decade ago, Silliman was buried knee-deep in salty marsh off the coast of Georgia, sampling blue crabs from a cage. He looked up, and four feet away was a 12-foot alligator. Silliman couldn’t budge in the mud. So, he shook the cage as hard as he could. The alligator lunged, back flipped and backed off.
“Days later I was processing the whole thing and I thought ‘what the heck was that alligator doing in saltwater?” said Silliman.
He went out again to the same coastline at night, and with his headlamp saw gator eyes glinting back at him every two yards.
“They were everywhere!” he said. Over the next several years, Silliman surveyed saltwater marsh sanctuaries all over Georgia and found an abundance of alligators.
“Everything we found was contrary to what we’ve always thought,” Silliman said. “Alligators are a top marine predator. They eat sharks, they eat manatees, they eat fish.”
A global phenomenon
This paradigm shift is happening all over.
Dr. Alejandro Martínez Abraín in Galicia, Spain also studies predators. He’s noticed otters, wolves and bears are showing up outside their “typical” habitats. Wolves and bears frequent cities, villages and roadsides. Eagles are nesting in trees, not just remote cliffs.
“Now that most people in Europe live in a few large cities and their attitudes towards wildlife have changed, animals can get out of their refuges and re-colonize former territories,” said Martínez Abraín.
Re-colonizing old haunts?
Silliman thinks top predators have always been this adaptable. But humans pushed predators into areas where we didn’t want to live, like swamps, jungles and mountain tops. These marginal places became refuges. As their populations increase, predators are simply re-colonizing areas where they used to thrive.
That’s not a bad thing.
Predators play an important role in balanced ecosystems. For example, sea otters are crucial for sea grass ecosystems, which in turn provide breeding ground for countless fish we like to eat.
The benefits of predators are well documented
The University of California, Santa Cruz documented that when sea otters moved into declining seagrass meadows off the coast of California, the seagrass rebounded.
The otters helped by eating crabs. Crab populations were out of control before sea otters, and they gobbled up most of the sea slugs. Sea slugs keep algae under control, and without them the area had become choked by algae. But the presence of otters restored sea slugs, and the grasses followed.
But how do we co-exist?
Despite the benefits of predators, humans must respond when interactions with predators get ugly.
Although we don’t have data on alligator populations in North Carolina, nuisance alligator calls to the North Carolina Wildlife Resources Commission (NCWRC) are on the rise, from around 50 calls in 2015 to 150 in 2017.
That’s why the NCWRC has decided to allow a limited number of alligator hunting licenses in three areas of Hyde County. The alligator hunting season will run September 1 through October 1.
Silliman thinks this is a good thing. “Hunting will help control population,” he said. “We can put limits on where these animals are allowed to exist.”
Public education is crucial, says biologists
Both Silliman and Martínez Abraín agree that educating the public is a no-brainer.
Silliman said we have good examples. In Florida, there are a healthy number of alligators— more than 3 million. Floridians know to walk about 20 feet away from lakes. There are more black bears in Buncombe County, NC than anywhere else in the state. Asheville-ians know to lock up their trash and walk in groups at night.
Martínez Abraín said it’s not only our behaviors that must change. Our perception must also evolve.
“We have learned that our perception of wildlife was completely wrong,” he said. “Our future relationship with wildlife will be one of coexistence. Probably it is the first time in human history we are facing that situation.”
- Rossie Izlar
Rossie Izlar is the associate producer on the UNC-TV Science team.