Leonardo DiCaprio won the Best Actor Oscar for The Revenant in 2016 but arguably wasn’t the real star of the show.

The film recounts the true story of 19th century fur trapper Hugh Glass, who was so badly mauled by a grizzly bear near the Missouri River his mercenary colleagues left him for dead in a shallow grave, from which he duly escaped to seek vengeance.

The bear attack is an extraordinary piece of filmmaking and has lingered in the public imagination ever since, inviting the question: what should you do if you find yourself facing off against a slavering grizzly?

Here’s the answer.

Precautionary measures

If you’re camping or hiking in the woodlands of North America – particularly Canada, Alaska, Washington, Idaho, the Dakotas or Montana – or in parts of northern Europe and Asia, it’s perfectly possibly you could encounter a large bear.

When passing through known bear country, you should be sure to make noise to alert them to your presence. Bears might regard any attempt to cross their territory stealthily as the behaviour of a threat and initiate an attack as a defensive measure. Talking, clapping or singing aloud could help remove any doubt about your intentions.

Watch out for evidence of their presence, from excrement on paths to the remains of animal carcasses. If you are lucky enough to spot a cub, rest assured their mother is not far behind and will defend her children to the death. This is where Hugh Glass went so badly wrong.

Keep your dog on a lead in case they race off, encounter a bear and provoke it, risking getting clawed to pieces themselves or leading an enraged grizz straight back to you. Unless your dog is Baxter from Anchorman, their intervention is unlikely to be helpful.

When eating or preparing food, be sure to do so far away from your campsite. Any leftovers should be sealed in Tupperware boxes as bears have a powerful sense of smell and might be drawn by its tantalising odour like Yogi to a picnic basket.

If you’re proposing to camp, ensure you have a tent large enough to accommodate a makeshift protective wall of rucksacks and equipment inside. This could prove a lifesaving defence in the event that an aggressive bear goes for you in your sleeping bag, a highly rare occurrence but not entirely unknown.

Types of bear

At this point, it’s important to distinguish what kind of bear you’re up against.

The grizzly is by far the bigger threat, a burly devil with a pronounced hump of muscle at the shoulder. Grizzlies can grow as tall as six foot five and have powerful jaws and long, sinister talons, ideal for digging up roots or disembowelling prey. You can distinguish it by its shaggier, silver-tipped fur.

A black bear, by contrast, has no such hump and is far more slender. It can be black but also various shades of brown to blonde. Less aggressive than its larger counterpart, it poses a different threat by being better able to climb trees.

Neither kind wants to attack a human for its own sake and will only do so in response to a perceived threat to themselves or their offspring or if they have reason to believe you might be food – bears are omnivores and will eat almost anything.

Grizzlies

If you encounter a grizzly bear, the first thing to remember, as with sharks, is: stay cool.

Panicking or screaming will alarm the bear and cause it to attack, either to quell a threat or eat you, depending on how it interprets your behaviour. This is where adventurer Timothy Treadwell and his girlfriend Amie Huguenard went wrong, as documented by Werner Herzog in the harrowing Grizzly Man.

Making no sudden moves, you should stay still and speak to it reassuringly in a calm, steady monotone. This at least confirms you are human, a species about which bears are broadly ambivalent.

From here, a bear may walk away or become agitated. You’ll know if it’s the latter because the animal will pin its ears back, dip its head and nod from side to side, pawing the earth and emitting a low growl of warning.

If it meets your gaze, it is about to attack. Dropping its jaw means it’s about to charge. It might plan to feint by charging at you and halting to see how you react or just knock you straight down.

Grizzly bear brawling at Yellowstone Park (Getty)

This is your moment to step back and attack it with pepper spray, aiming for the eyes and snout to temporarily blind and disorientate the creature. You should never leave home without this invaluable product when venturing into bear country. The good people at UDAP manufacture the market-leading brand, complete with natty “Griz Guard” holster.

Ideally, you should spray from 40 to 50 feet away, creating a fog of tear-inducing gas around you.

Unless you have maced your opponent, don’t try to run. Despite looking lumbering, grizzlies can hit top speeds of 30mph and won't hesitate to bring you down.

If you are charged, you should roll yourself into the foetal position, keeping your backpack on as an added protective shield and, as advised by the Wu-Tang Clan, protect ya neck.

The bear will not attack once it believes the threat is suppressed so play dead. And stay down. Grizzlies are suspicious beasts and known to return to the scene to double-check.

Black bears

These animals are less aggressive than the grizzly but are equally likely to attack if they feel threatened.

As discussed, black bears - common in Eurasia – are agile and adept at climbing trees so on no account ascend the branches to evade them. You might get away with it in the case of a grizzly but not here.

Asiatic black bears settling a dispute in Japan (Rex) (Rex Features)

If attacked by one these creatures, your best option is to stand your ground and respond in kind rather than hit the deck.

Shout, raise your arms to intimidate it and hit it in the eyes and snout with whatever weapons you have to hand, be it a rock, branch or hunting knife.

Hopefully, this will alarm the bear into a retreat.

Polar bears

Should you find yourself alone in the Arctic tundra staring down the largest land carnivore on earth, good luck.

This is actually more likely than it has been in the past as there is some evidence to suggest polar bears are being driven inland as a result of climate change melting the sea ice it uses as a platform from which to hunt seals and fish.

Plans to drill for Alaskan oil threaten polar bear numbers Show all 3 1 /3 Plans to drill for Alaskan oil threaten polar bear numbers Plans to drill for Alaskan oil threaten polar bear numbers The US government wants to open up Alaska to oil companies, threatening one of its two main polar bear populations PA/Getty Images Plans to drill for Alaskan oil threaten polar bear numbers Oil activity in the Prudhoe Bay area of the state has had a huge impact PA/Getty Images Plans to drill for Alaskan oil threaten polar bear numbers The 46,000 sq mile area, located between Alaska and the coast of the Russian Far East, holds 15 billion barrels of recoverable oil and a huge volume of natural gas

Intimidation tactics might work with a polar bear but remember they want to eat you rather than simply neutralise a threat.

Again, bear spray is your friend here but, honestly, you don’t have a lot of options. They can outrun you on open ice and snow despite weighing a tonne, will not be deterred by attempts to play dead and can kill you with a single swipe of the paw.