Even the most fearsome predators can share—if there's enough to go around.
In the first footage of its kind, an aerial drone has captured two 10-foot tiger sharks and a 13-foot saltwater crocodile scavenging a dead whale. It's also the first known record of the reptile feasting on a whale. (Watch an incredible bird's-eye view of a shark feeding frenzy.)
In September 2017, a charter company encountered a nearly 50-foot humpback carcass floating off Kimberley, in western Australia. A crew member deployed a drone and posted the video to social media, where shark expert Austin Gallagher spotted it—and knew he'd found something unique.
A dead whale is a smorgasbord for many marine animals, drawing diverse species that may not be commonly encountered together. That's why these scavenging events can be useful for scientists gathering data about wildlife behavior, says Gallagher, chief scientist and CEO of Beneath the Waves, a shark-conservation nonprofit based in Washington, D.C.
Pacific angelshark. Santa Catalina Island, California
"The most interesting aspect of this observation was seeing the overlap in time and space between tiger sharks and saltwater crocodiles, two apex predators that rarely encounter each other," says Gallagher, who led a study on the phenomenon in the Journal of Ethology.
The video shows that these species can scavenge on the same food source at the same time without any or much fighting.
"The animals do seem to have a respect for one another," Gallagher says.
Food Before Foe
"Tiger sharks are known to be highly opportunistic, and scavenging makes up a good portion of their diets," notes Antonella Preti, a trophic ecologist at the Southwest Fisheries Science Center in La Jolla, California.
Not as much is known about the scavenging habits of saltwater crocodiles. (Read how American alligators sometimes kill and eat sharks.)
One possible reason there was no aggression between the species is the size of the meal: A 20-ton animal means no shortage of meat.
"If there is a large food source to scavenge, a shark will try to get the most it can quickly before spending energy fighting," says Preti.
Gallagher also points out that the sharks in the video appear to have already gorged themselves to the point of exhaustion. "Sharks can only eat so much before it causes them to sink."
Although a lot of biological research depends on mathematical models, laboratory experiments, and sophisticated statistics, sometimes luck offers a window into the natural world.
That's why the video is an example of being in the right place at the right time to capture a somewhat rare natural event, Gallagher adds. (Watch what happens when a baby hippo plays with a croc.)
And the advent of aerial drones has made the possibility of detecting and recording such events likelier.
"Your eyeballs are the two most valuable tools that any scientist has," Gallagher says. "Adding drones to the mix just extends what our eyeballs can see.”
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