In recent years various large predators have appeared in unexpected places. Wolves have been spotted in coastal marine ecosystems, for example, while alligators in the US have made their way into salty waters. You might think these strange sightings are the result of climate change or just freak events, but according to a new study published in Current Biology, they are actually a sign that large predators are bouncing back and recolonizing areas in which they once lived.
Over the centuries, humans have decimated populations of large animals all over the globe. We ruthlessly hunted whales for their oil and meat, pushed tigers to the brink for sport and their prized orange furs, and killed most of Africa’s elephants for their ivory – to name just a few. Much of this occurred before biologists and conservationists began to study the habitats and lifestyles of these species, and the niches they occupy now were assumed to be their natural homes.
"The assumption, widely reinforced in both the scientific and popular media, is that these animals live where they live because they are habitat specialists," said Duke University’s Professor Brian Silliman in a statement. "Alligators love swamps; sea otters do best in saltwater kelp forests; orangutans need undisturbed forests; marine mammals prefer polar waters."
However, large predators have been appearing – or reappearing – in places we don’t expect, something the researchers of the new paper argue is actually a result of conservation, as the animals return to the habitats they once thrived in, before man and his rifle turned up.
The team looked at dozens of surveys and studies of a variety of creatures, including alligators, sea otters, gray whales, mountain lions, orangutans, and gray wolves, and found that many predators are now more numerous in “novel” ecosystems than in the habitats where we traditionally expect to see them.
They argue that this is not the result of climate change, as the animals aren’t moving to new climates, or random sightings of lost animals, as the critters are appearing in abundance. Therefore, the likely explanation is that as their populations resurge, the animals are reclaiming the habitats they historically lived in.
"We can no longer chalk up a large alligator on a beach or coral reef as an aberrant sighting," said Silliman. "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."