Burrowing Echidnas Act as Natural Hoes
When we talk about ecosystems, we often talk about the food chain, and the ways in which each plant or animal affects others around it. But we don’t often think about the impacts of each creature on its environment. Case in point: the humble echidna, which, researchers now say, can aerate tons of soil every year in its native Australia. A report on the echidna’s contributions was published in the Journal of Experimental Biology.
The echidna—better known among readers of a certain age as “Sonic the Hedgehog’s friend”—is a strange, strange beast. It’s got spines like a porcupine, uses electrosensing to hunt like a shark, and lays eggs like its cousin, the platypus. To give you some idea of what an echidna looks like in motion, check out these adorable little weirdos at the Columbus Zoo:
It’s not a particularly fast animal, nor is it particularly fierce, and exactly how it spends its time has been something of a mystery. (Cue dramatic music) Until now.
Researchers at three Australian universities have made the short-beaked echidna (Tachyglossus aculeatus) their business. They traveled to the woods east of Perth one summer and tracked down 11 different adult echidnas, videotaping each one as it wandered past. Then they caught them and fitted each one with a radio transmitter, GPS tracker, and accelerometer to trace its movements. Before releasing their test subjects, the researchers held them and wiggled them around a bit to calibrate the accelerometers.
Every one to four days, the researchers followed the radio signal to catch each echidna and download the data from its sensors, which amounted to a little more than an hour of movement data per critter. Then the next year, the team did the same thing all over again in the spring.
The data showed a huge difference in seasonal echidna activity. In the spring, the animals trundled about at a “stately” pace, averaging about 0.3 meters per second. Come summer, when temperatures could reach 90 degrees Fahrenheit, echidna life became equally extreme. The animals spent most of the day staying very, very still, but when they had to move, they “sprinted” between spots, easily doubling their springtime speeds. “They certainly try to avoid really hot temperatures,” said study co-author Christofer Clemente in a statement.
During the team’s tagging trip into the woods, Clemente had noticed lots of little gashes in the ground where the echidnas had gouged out their insect meals and wondered if these dig sites were numerous enough to be changing the landscape. He looked over the data from the echidnas’ trackers and found that the animals spent as much as 10 percent of each day moving earth around. Using this, and what he knew about the echidnas’ digging skills, Clemente calculated that each one could easily move about 200 cubic meters, or more than 7000 cubic feet, per year, about the volume of an Olympic-sized swimming pool.
This is important information not only for the echidnas and their subterranean prey, but also for scientists and conservationists.
“They are probably one of the last really big bioturbators [soil mixers] left in Australia,” Clemente said, “which means that they are really important for the environment."
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