Koalas face many threats, but cows are seldom thought among them, at least not directly. Certainly, some of the habitat loss that poses the furry marsupial’s greatest danger may be motivated by desire to open up more grazing land, and bovine contributions to global heating pose a risk to millions of species. However, the possibility that cows are trampling koalas to death is little investigated. One scientist is on a quest to discover how common the problem might be, and has strapped a cuddly toy koala named Kokonut to a remote control car to find out.
Koalas make unlikely bovine victims since they spend the majority of their time in trees well above any cows, unreliable reports of lunar leaping aside. However, koalas do need to come to the ground to travel from tree to tree and to get water. A great many of their deaths are attributed to being hit by cars and savaged by dogs in the process. However, there may be another threat posed on these journeys.
“For years veterinarians, farmers, and wildlife carers across Australia have been reporting serious injury or death of koalas due to cow trampling,” said University of Queensland PhD student Alex Jiang in a statement.
More humans are killed by cows each year than sharks and snakes together, after all, and seldom in some Pamplona-style running with the bulls scenario.
Jiang told IFLScience an online survey of wildlife carers and those most likely to have encountered koala trampling received between 10 and 20 accounts of incidents. Although these took place over many years, he suspects such encounters are most common at night, and therefore seldom seen.
Nor are gentle but near-sighted herbivores treading on koalas by mistake. “This is largely based on animal autopsy evidence, mainly finding hoof prints on dead koala bodies – they’re clearly acting aggressively to these poor animals,” Jiang added. “There are witness statements from farmers confirming that cattle have been seen chasing koalas in paddocks.”
To determine how aggressive cows really are to koalas Jiang put Kokonut the stuffed koala on a remote control off-road vehicle, sprayed it with koala urine and feces for that authentic soggy-bottom smell, and is driving it through herds of cows. He’s also taking a similar car, without koala on board, for drives as a control.
“If the cattle react differently to the car with the faux koala, that is, they’re more aggressive than with the regular RC car, we can be confident that their reactions are because of the fake koala," he said.
Jiang admits this is one of the study's more creative methods for gathering data.
“We haven't seen any actual attacks yet, but they do pay more attention when the stuffed animal is on the car,” Jiang told IFScience; “We have also noticed some ritualised aggression such as ground digging and warning calls.”
Jiang hopes to learn the conditions under which attacks may occur, suspecting the koalas are perceived as a threat during calving season. He added reports of damage to other wildlife are rare, perhaps because they are either too small to attract bovine attention or fast enough to get away.
Jiang is also tracking how koala ranges change when cattle are introduced nearby. He stressed to IFLScience that cows are far from koala's greatest threat, but thinks we need to be aware of even rare dangers, particularly as moves ramp up to combine koala-suitable trees with beef grazing.