Decades of poaching and habitat loss have put just a bit too much pressure on the normally passive giant anteaters of South America. As a result, the seven-foot-tall, heavily clawed insect eaters have started to kill hunters in self-defense.

According to a paper published in the journal Wilderness and Environmental Medicine, the Brazilian anteaters in each case felt cornered and lashed out defensively. The researchers, from four Brazilian universities and government agencies, say these attacks are rare. But they indicate that the boundaries between humans and wildlife are disappearing, which could lead to more conflicts.

Giant anteaters are considered vulnerable to extinction, with a population decline of at least 30 percent over the past decade. The animals have lost much of their habitat to development, agriculture, roads, and fires. They also are heavily poached for their meat and as trophies. The animals have disappeared from four countries and may be on the way out in several others.

In 2010, an anteater used its knifelike claws—which are normally used to tear apart anthills—to puncture the femoral arteries of a 75-year-old man who was hunting in the animal’s forest habitat in 2010. The second fatality occurred in 2012 when a 47-year-old farmer was hunting with his sons and dogs. The father approached the anteater with a knife, only to have the animal stand up, grab him into its forearms, and inflict deadly wounds on his arms and legs.

“These injuries are very serious, and we have no way of knowing whether it is a defense behavior acquired by the animals,” lead author Vidal Haddad Jr. of São Paulo State University told AFP.

These are the first fatal giant anteater attacks on humans described in scientific literature, but another case occurred earlier this year in the South American country of Suriname. In that incident, a 43-year-old man chased after an anteater with a machete, intending to kill it. Instead, the anteater inflicted fatal wounds along the man’s neck, arms, and shoulders.

In response to that incident, Mariella Superina, chair of the International Union for Conservation of Nature’s Anteater, Sloth and Armadillo Specialist Group, released a statement stressing that the public should not be afraid of the animals.

“I have never heard of an anteater proactively and aggressively attacking a person or an animal,” she said. “I am only aware of two other deadly attacks of giant anteaters. One was a poacher whose dogs attacked a giant anteater, and the animal defended itself with its claws, eventually inflicting deadly wounds to the poacher. The other one was an accident at an Argentinean zoo, where the animal was cornered and feeling threatened by a caretaker who did not follow the basic safety protocols.”

That caretaker, a 19-year-old woman, died in 2007 after surgery to amputate her mauled leg. “In both cases, as well as in the one that just occurred in Suriname, the giant anteaters felt threatened and tried to defend their life, which is something you would expect from any wild animal.”

The incident in Suriname illustrates some of the myths that surround giant anteaters. The man who chased the animal did so because locals suspected it of killing and feeding on two calves, something the toothless animal would not have been capable of doing.

According to a 2012 study about giant anteater folklore published in the journal Edentata, myths about the species include their ability to kill jaguars. (In truth, jaguars prey on anteaters.) They also are often perceived as omens of bad fortune, the only cure for which is to kill the animal and wear its claws as an amulet.

It’s too bad the giant anteaters can’t do something to change their own luck.