In this blog, Panthera Tiger Program Director Dr. John Goodrich transports us to the snowy regions of northeast Asia — the home of wolves, bears, leopards and Siberian tigers. After stumbling upon a shocking tiger kill, he recounts how he began to understand the complex relationship between tigers and bears in this challenging environment. Navigate the snowy oak forests with Dr. Goodrich as he brings to light the important conservation implications of these interactions.
A few decades ago, when I lived and worked in northeast Asia, I was tracking a male tiger named Dima that we had captured and fitted with a radio collar a few months before. He was the biggest tiger we would catch in 20 years of research in the area, and at 455 lbs, the circumference of his head was bigger than my waist and the base of his tail was as thick as my thigh. He had been moving through an area where people had summer gardens and grazed cattle, so I was having a look around to make sure he wasn’t getting himself into trouble. But what I found that day blew my mind.
I followed his tracks in light patches of early spring snow. Here — we saw he meandered through a park-like oak forest. And there — suddenly, as he approached the edge of a steep embankment, his tracks became spaced very close together. He crouched into a stalk. And when I looked over the embankment, I was shocked. Before me was a large, partially-eaten brown bear sow.
I jumped down to examine the carcass and immediately noted a single, bloody hole in her neck that was clearly an entry wound. Her tracks showed that she had ambled along the base of the embankment and seemed to suddenly fall down dead, with no sign of the struggle one would expect from a huge tiger killing a bear nearly his own size. I concluded the bear had been shot and Dima just took advantage of a free meal, but why hadn’t the hunter claimed such a valuable prize? Then I turned the bear over to inspect the exit would. To my surprise, I found two more entry wounds! I revised my conclusion — Dima had leapt from the bank onto the bear, dispatching her with a single bite to the nape of her neck, almost before she was even aware of his presence (one of his canine teeth had broken prior to our capturing him, hence only three bite wounds). The power and skill required to do that was unimaginable. I collected some samples and vacated the area, hoping Dima would return to finish his meal, which he did, though it took him several days to devour such a large animal.
Fascinated, I went home and began combing through local literature and speaking with my colleagues on the subject. There were numerous reports of tigers preying on both brown bears and Asiatic black bears, but the relationship, it seems, was not that simple; there were also reports of bears killing tigers. As the years progressed and we tracked both bears and tigers, the picture of a complex relationship emerged. The largest brown bears — and we recorded bears with weights up to 800 lbs in the area — would usurp kills from tigers and even track them from kill to kill (meeting those bears when searching for tiger kills is another story for another day!). In one case, tracks in the snow told the story of a tigress and bear reluctantly sharing a red deer the tigress had killed. The tracks suggested some bluffing and blustering on the part of both species, but no actual fighting. Rather, it seemed when the tiger had eaten its fill for the day, the bear was able to scare it off, but when the tigress returned hungry and the bear’s stomach was full, the bear would yield to the cat. Once, my colleague Ivan came home from tracking a tigress and told the story of how it spent the better part of a day trying unsuccessfully to pull a black bear with cubs from her winter den.
Dima killed several more bears in the following years that we tracked him, and not all kills were so clean and efficient as my first discovery. At the site of his next kill, another female brown bear, I found a gruesome scene with a huge swath of flattened vegetation where the bear fought for its life. Small trees had been bitten in half, and those that remained standing were splattered with blood. After the fight, Dima spent four days in the area and completely consumed the bear. Why did Dima take such risks? Bears are among the most powerful animals I know, with formidable teeth and claws. Wouldn’t sticking to red deer and sika deer make more sense? While we will never know for sure, I suspect his predation on bears served another purpose than just filling his belly. Likely, he was taking out the competition — the same animals that might kill his cubs or steal the kills of one of the three tigresses with which he shared his territory.
Understanding these types of relationships is important to conservation. For example, if we are working to recover tigers, what are the implications of bears taking their kills (reduced energy intake might mean lower survival of tigers and their cubs)? What impacts will tigers have on bear (and wolf) populations? Amur tigers have recovered from an estimated 40 individuals in the wild about 75 years ago to an estimated 400 today. But during that time, for instance, the local wolf population has plummeted, likely due to displacement and predation by tigers. We don’t want another species to go extinct due to our recovering tigers. While this has not been a concern because both wolves and bears are widely distributed across Eurasia, it is a concern in the southern region where the world’s remaining 40 or so Amur leopards overlap with tigers. Indeed, during our work there, a tiger did kill a leopard. Research in India has shown potentially significant impacts of tigers on leopard abundance and behavior, and that will be the subject of a future blog post. But in the snowy forests of Asia, far at the northern edge of the tiger's range, I saw firsthand the dance between two massive predators — bears and tigers. It was a dance that resulted in death, food, struggle — and for me, insight. Now, I could better understand what it means to protect not only tigers, but all animals.
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