European rabbits are making themselves right at home on the continent of Australia. Although they’re not native to the region, they spread like wildfire when they were introduced, tantamount to an invasive species.
Once in, they caused some issues for the local wildlife, as well as for farmers, but one place they really weren’t ever seen was atop the mountains, just above the snow line. Why though? Mostly because the grass they eat would be covered by snow and ice, so this meant they’d have trouble getting to food to survive.
On the other hand, more and more of these rabbits are being seen above the snow line in New South Wales, and experts are starting to take notice. So just what are they surviving on if they can’t get to the grass to remain consistent with their traditional diet?
Fecal samples that were taken and shipped off for dietary analysis revealed that the rabbits were eating snow gum leaves, more commonly referred to as eucalyptus, as the primary part of their diets. The findings are published in the journal Australian Mammology.
Theoretically, these leaves should be toxic to the rabbits because of the chemicals they contain. How exactly the rabbits are getting away with chowing on these leaves and continuing on with their energetic lifestyles is baffling scientists.
One theory, proposed by researcher David Lee from the University of the Sunshine Coast in Queensland, is that the leaves may be freshly-regenerated following recent brush fires and this may mean they’re less potent with the chemicals that typically make them toxic than older leaves would be.
Adding more confusion to the whole thing, these leaves don’t have a whole lot of nutrients to offer for energy, which is why lazy koala bears with low-energy lifestyles are known to live off the stuff. They’re also particularly difficult to digest, so have these rabbits evolved in some way to be capable of digesting them?
Due to the leaves’ low yield of energy, it’s hard to believe the rabbits are able to carry out their typical active lifestyles. Their difficulty of digesting them even has scientists thinking the rabbits could have evolved with some kind of gut microbe capable of doing so.
Although little is known about the rabbits’ lifestyles or health from a simple stool sample, experts do note that the rabbits continue to reproduce in the region, which suggests their health isn’t being hindered by the supposedly “toxic” plants.
Source: ABC