It’s not every day you see a bear rumble going down right along an international border. Well, count this as a special day, then:

The bruin brawl took place at the Russia-China line in the late evening of May 11. The trail camera that captured the event was one placed in the Russian Far East by the non-profit Amur Tiger Centre to monitor reintroduced Amur (or Siberian) tigers. Indeed, the very spot at the border fence where these Ussuri brown bears squared off has been used by a tigress called Lazovka to slip between the two countries (including in company with her cub). As the Centre rather poetically puts it, these were "bears fighting on the tiger paths."

We’re not sure what kind of geopolitical symbolism or significance can be read into two burly beasts on opposite sides of an international boundary duking it out, but the short, fragmented clip is definitely dramatic: The contestants wreak some major damage on the fence – which follows the Amur (or, as it’s called in China, the Black Dragon) River – in the process, paying no apparent heed to the incorporated barbed wire.

"Amur tigers have always walked here in peace and quiet," the Amur Tiger Centre team is quoted in a Siberian Times article on the bear fight, "yet the bears broke everything as soon as they came!"

It's not uncommon for researchers to find photos and footage of camera-destroying bears when checking their data. Photo: Viktor Kuzmenko/ The Amur Tiger Centre

A recent post by the Tiger Centre documenting its June reconnaissance of the region’s camera traps related that a number of the cameras were damaged by curious bruins.

That Tiger Centre post notes its team isn’t certain of the sex or age of the bears involved. Brown bears aren’t considered strongly territorial, though much of the time they basically avoid one another; males (boars) tend to wander larger home ranges that overlap with several female (sow) ranges. Encounters with other bears are most frequent at major, localised food sources – fish runs, garbage dumps, animal carcasses, etc. – and during the breeding season, which typically runs from late spring into early summer. Even if they don’t seem to actively defend territories, boars do tend to sort out a rough hierarchy amongst themselves, and when attempting to monopolise sows in heat – or squaring off over food – they occasionally come to blows, which can be violent and protracted. 

Whatever the cause of the altercation in the Amur Tiger Centre’s camera-trap footage – and whatever the outcome, which wasn’t captured – it’s certainly a stark demonstration of the belligerence and heavy-hitting power of brown bears, one of the planet’s largest and most powerful carnivores. (We wouldn’t want to have been that border fence, needless to say.)

It’s also a reminder of the overlap in this special part of the world between the mighty brown bear and the Amur tiger, which shares the mantle of heftiest cat on Earth with the sleeker but similarly sized Royal Bengal tiger.

A tigress called Lazovka is known to use trails along the border to move between Russia and China. Photo: Viktor Kuzmenko/ The Amur Tiger Center

Tigers and bears have what you might call a complicated relationship: The big cats will prey on both Asiatic black bears and brown bears, though in the latter case the biggest male bears may well be off-limits; brown bears, meanwhile, sometimes trail tigers to scavenge their kills – or actively steal them. A 2011 review of interactions between Ussuri brown bears, Asiatic black bears, and Amur tigers in Russia’s Sikhote-Alin Nature Reserve recorded evidence both of tigers killing bears and bears killing tigers, and found that close to 17% of tiger kills were scavenged by bears, primarily browns. As the Tiger Centre notes, mutual avoidance is probably very often the name of the game when it comes to tigers and brown bears.

(And hey, if your appetite’s been whetted for more trail-cam bear brawls, just check out this similarly nocturnal match – likely just a bit of rough play – between two American black bears in North Carolina from a few years back.)