The insatiable appetites of feral pigs mean that some staple species of Australian wildlife can face unwelcome harassment and even have their status endangered.
Unlikely as it seems, wild pigs have targeted sea turtles as food sources. And their voracious feeding habits are indirectly affecting the fate of koalas. The gluttonous swine gorge on any foliage they come across, which means wrecking the leafy landscape and its surrounds that the koalas frequent.
The koala population is in enough trouble as it is, due to the effects of defoliage and the last thing that they need are feral pigs having an unwanted influence. Make no mistake ‑ if the pigs need to nosh, their instincts know no bounds. When drought has gripped in areas frequented by hogs, there are tales of desperate groups of them attacking tiny calves.
Deborah Tabart, CEO of the Australian Koala Foundation, has not seen any evidence on her many travels around Australia, to consider feral pigs an immediate danger to koalas but is still concerned.
“I have never heard of wild pigs eating eucalyptus trees, but I wonder whether their destruction of the ground when they burrow for food would stop the regrowth of koala food trees,” she said.
Deborah resides in Queensland but her roving duties take her all over the continent. She worries that attempts to eradicate certain pest creatures can have a rebound upshot for other breeds of wildlife. Perhaps baits put down could be munched by unknowing innocent parties such as pets wandering onto properties they shouldn’t.
“I remember on Kangaroo Island, when our teams were researching landscapes, seeing a huge, I mean huge, feral pig that just appeared to be burping after eating a bait. He was enormous, like the size of a hippopotamus,” she claimed.
The pigs themselves are faced by apparatus and tactics to curb their antics but they give the impression of being as clever as they are brash.
“There were pig cages all over the island. Big cages!” said Deborah.
If the koalas have largely escaped direct suffering at the hands of the marauding feral pigs, other groups have not been so lucky. It is estimated that there are least three million porkers, perhaps even more, roaming Cape York Peninsula, eating whatever they can.
They possess the perfect genetic credentials to survive and thrive in this harsh tropical landscape. As the pigs multiply, they ride roughshod over other species. This is certainly true in the case of the turtles that breed along the beaches of Western Cape York.
In many examples, including one as reported by the ABC, feral pigs are preying on nests of newly-hatched flatback and green turtles along the north Queensland coast. The pigs are apparently guzzling a combination of eggs in nests and turtle hatchlings.
Feral pigs dig up turtle nests not long after mother turtles lay their eggs in the sand, then wolf them down and often come back for another helping when the eggs are close to hatching. At some locations, Rangers and scientists have observed 100 per cent of turtle nests eradicated by pigs. Other raiders will chomp on turtle eggs – dingoes and goannas in particular ‑ and various creatures try to move in on the hatchlings as they crawl along the dunes on their way to the sea. But the pigs scoff more eggs than other killers, and there are so many of them that the turtles don’t stand much of a chance.
“In northern Queensland, feral pigs are still an issue in relation to the turtles,” said Christine Hof, Marine Species Project Manager with the World Wildlife Fund (WWF).
“It is a real challenge to address the threat of feral pigs but there are organisations which are having success.
“The Western Cape Turtle Threat Abatement Alliance is one of those. They are doing some incredible things.
“Don’t forget the turtles are also under threat from goannas, plastics being washed ashore as well as climate change.
“It is a finite balance between native and feral animals and very complex.”