| 1 | The land version of a great white shark |
It’s said that a brown bear will eat almost anything, and it’s mostly true. Ursus arctos is not only an omnivore, but one of the most omnivorous animals on Earth, beating the black bear by virtue of its superior hunting capabilities.
Brown bears have been recorded eating over 100 species of mammals. They’re known to eat snakes in Japan, frogs in Italy, ants in Slovenia, moths in Yellowstone. Their plant foods include berries, flowers, roots, acorns, shrubs, grasses, and they have no problem guzzling down pizza or beer. The only animal with as varied a diet is the human, but that’s only because we can visit a supermarket and pick anything to our heart’s content. Bears have even been spotted eating mushrooms, including the red and white spotted deliriant ones that inspired Super Mario.
A bear’s diet switches wildly with the seasons. Spring is a scarce season for food, with neither berries nor salmon. So instead, brown bears dig for roots en masse, with one of their favourites in Alaska being sweetvetch. Grizzlies are far better at digging than black bears due to their longer claws and powerful forelimbs (though black bears are better at climbing trees).
In summer, grizzlies often hunt for acorns, which are fatty and extremely filling. Their strategies are to climb a tree, slowly and very haltingly, raid the secret stashes of squirrels nearby, or simply pick up acorns which have fallen to the ground.
| 2 | Salmon bonanza |
Despite its reputation as a savage, flesh-eating monster who gnaws on the bones of hikers, the average brown bear’s diet consists of 80-85% plant matter. However, this all changes when coastal areas come into play, as the sight of the sea will awaken any bear’s love for salmon. Bears eat other fish species such as sea trout, but salmon is special. On Kodiak Island, or the famous Brooks River of Alaska, a bear with access to salmon will quickly make it 95% of its diet. They will spend two months by the salmon river, jockeying for position with other bears, and eating almost non-stop.
A bear in hyperphagia, the pre-hibernation feeding frenzy state, can eat 30 salmon day, and up to 58,000 calories. They normally go for the fatty brains first, followed by the roe, while chucking the entrails away. But sometimes, Alaskan rangers have seen a bear take a single bite of a salmon and discard the carcass into the river. The goal is maximum nutrition for minimum effort.
Salmon is special for a bear because of its huge fat content (the source of your omega 3 fish oil pills) and decent protein. It’s incredibly easy to digest for bears, and consequently, a grizzly by Brooks River can gain 3 pounds of fat (maybe some muscle) a day. Salmon is why coastal grizzlies are so huge compared to inland ones, which rely more on berries. A Kodiak bear averages at 800-1200 pounds, while a grizzly in Alberta clocks in at just 500-700 (for males).
| 3 | Bear-berry relationship |
The worst thing a blueberry farmer could possibly do is employ a bear as his new field picker, because if there’s one thing bears love more than honey, its berries. They’ve been documented to eat over 100 type across the world. One Alaskan species with a 2cm diameter and a bright red colour was even named the bearberry because of the grizzly’s fondness for it. In Yellowstone park, they love huckleberries, buffaloberry, twinberry, and serviceberry, while in Alaska, the inland bears snack on elderberries and lingonberries.
Despite being so small, berries are vital for a bear to fatten up for the long cold winter. In Denali, an adult male grizzly will typically eat 200,000 blueberries per day, while Banff’s grizzly bears can reach 200,000 buffaloberries per day. One time, a female grizzly was observed eating berries non-stop for 14 hours, chewing unceasingly, except for one half hour rest. It’s enough that park rangers typically warn hikers to not go too mad with the berry picking in summer. When the first schools of salmon appear in July, bears will gorge on them and totally forget about berries, with salmon making up 95% of calories, but in central Alaska, where fish is less abundant, berries can be a bear’s main food supply.
Instead of the flexible fingers of humans, bears pluck the berries with their prehensile lips, lips which are muscular and can bend and grasp a branch in order to snap the fruit off.
| 4 | How often do they prey on larger animals? |
If properly motivated, a brown bear can take down almost any prey it wants. A buffalo is no problem, with a quick sledgehammer blow to the back that shatters its spine. Younger bears however, can be very reluctant to give chase, lacking confidence. Their early hunting attempts can be very half-hearted, with the elk or moose escaping easily. A bear doesn’t compare to a Siberian tiger, which pounces and pierces its prey’s jugular vein with ruthless efficiency. Bears are far clumsier, usually pinning their prey with their massive bulk and eating them alive. Bears couldn’t care less about the “pride of the kill” – they go straight for the weakest and most infirm animals.
Most of a bear’s large mammal prey comes not from fresh kills, but recently deceased corpses (carrion). This is particular favourite in spring, when a brown bear has just left its den and is still in a sluggish state of “walking hibernation”. The elk carcasses it finds are often frozen solid following a long winter, so to warm them up, the bear will sometimes sleep on them overnight.
Because of all this, bears are classified as an “unskilled predator”. They lack nuance, but get away with it due to being, well, bears. If your life’s ambition is to hug a wild bear, then don’t try it in the Canadian Yukon; scientists have proven that bears become more carnivorous the further north you travel.
| 5 | Moose and friends |
A bear’s favourite large prey is the ungulate family – elk, moose, deer and cattle (and technically giraffes and rhinos). Anything with hooves will do for a hungry bear. Bears are skilled at exploiting terrain as well. A moose, for example, has very slippery hooves, making it easier for bears to catch up with them on snowy surfaces. The same applies on muddy, soggy riversides, which starving bears will often wait on for prey.
The fact that bears can run at 35mph helps, although a caribou could easily outrun them in open terrain. Believe it not, a brown bear can decapitate a moose with a single swipe of its paw, sending it flying over a riverbed. Another crafty strategy is to charge at a herd of deer and send them fleeing, to make the slower, weaker ones reveal themselves. Separating a cub from its mother is yet another tool in the box. One time scientists tracked bears in Alaska with GPS, and found an average calf kill rate for moose and caribou of 34.4 over 45 days. One bear managed 44 over 25 days.
As for deer, bears have been recorded eating 100 species around the world, and larger ones are their favourite. Smaller deer like roe, white tailed deer, and red deer are occasional meals, but are far too nimble. Their small size means that there’s no easy target for a swiping bear paw. In some countries bears hunt far more ungulates than usual, like Sweden, where moose makes up 70% of their diet, and the local bears seem particular skilful in hunting them.
| 6 | Human trash |
The old chestnut of advice says that if you feed a bear garbage, it will come to associate humans with food, perhaps even you personally. It’s completely true, to the extent that if a grizzly bear pinches a lost apple which somebody left on a picnic bench, its imprisonment is almost inevitable. Just one bite can set it on a course for bear jail.
For example, sow 101 was one of the most beloved grizzlies in Yellowstone park. From 1982- 2002, she raised 3 or 4 sets of cubs, and gave scientists valuable data from her GPS tracking collar. One night in 1993, she strayed into the town of west Yellowstone, and spent the whole night feeding on loose garbage. Rangers shunted her away, and all seemed well, but one day in the early 00s, 101 was starving. Maybe the annual miller moths hadn’t turned up, or maybe the berries were withering that year. Her long bear memory kicked in, and she returned to the same garbage feeding ground she had last visited 10 years ago.
This time, she kept returning, and the inevitable happened: 101 was imprisoned in a wildlife sanctuary. There was no way for her to co-exist safely with humans, even if dumped on the opposite side of Yellowstone by helicopter, because bears can easily travel 100s of miles in a year.
So it’s not just black bears who love pizza and stale orange peels. On a happier note, Sow 101 lived to the ripe old age of 38 at the Grizzly and Wolf Discovery Centre, euthanised in June 2020.
| 7 | Is their honey obsession real? |
They’re slightly less obsessed than the fairytales portray, but bears really do like honey a great deal. A bear’s thick hide is virtually immune to bee stings, so after climbing a tree using its limited tree climbing ability, the grizzly will just reach into the hive and scoop the honey out.
What the children’s classics didn’t mention is that bears also eat the protein-rich bees themselves, and the larvae. As opportunistic scavengers, no morsel of food goes to waste. The bees try to sting the bear, but normally bounce off. Once it’s done, the bear runs off and shakes its body to remove the bees, as though shaking water away after a swim.
In the first 5 months of 2018 alone, the Finnish government handed out 143,000 euros in compensation to beekeepers, and 370 beehives were destroyed by bears in Finland and northern Estonia. Papillon the escape bear is one honey lover. When he awoke from hibernation in March 2020, 6 months after leaping an electrified fence, one of his first moves was to roam the Italian province of Trentino raiding beekeepers’ hives.
Electric fences are popular deterrents, but one beekeeper in Turkey had a better idea: he decided to turn the local bears into taste-testers, by placing 4 samples of honey outside his farm. He waited to see which honey the inevitable bear visitor would go for, and the answer was the Anzer variety, over the flower honey, chestnut honey, and cherry jam decoy.
| 8 | Rips apart squirrel dens |
Despite the bear-moose royal rumbles that constantly happen, most of a bear’s meat-eating comes from smaller mammals. This includes hares, marmots, ground squirrels, pikas, chipmunks, mice, rats, voles and lemmings.
Inland bears living on tundra have a tendency to hide at the entrance of arctic squirrel nests, and pounce when they emerge in the morning. These squirrels weigh 2 pounds, a decent chunk of meat, and the bears tend to succeed most in October and November, just before hibernation, when the mounting snow blocks off the squirrels’ escape routes. Bears in Denali are particularly obsessed with arctic squirrels.
Bears commonly use their long claws, which evolved specially for digging, to completely rip apart the dens of small mammals and scoop them out. Sometimes they launch these assaults as the squirrel hibernates, if the bear wakes up from its own hibernation a couple of weeks early. The promise of a tasty squirrel and the nuts it has stashed are irresistible for a bear. A Siberian chipmunk’s winter stash, for example, can contain 8.8 pounds of food. The first stage is locating the dens, and here, grizzlies are helped by their superior sense of smell.
It varies by subspecies as well. The Tibetan blue bear of the Himalaya is obsessed with Tibetan pika, deriving nearly 60% of its calories from it. 25 pika have been found inside a single Tibetan blue bear’s stomach.
| 9 | Bears love insects |
What is the point of a 1000 pound grizzly bear tucking into a meal of 5-10 delicately arranged ants? We don’t know either, but while the majority of grizzlies wouldn’t bat an eyelid at Flick and his friends, certain grizzlies can get a massive chunk of calories from them. The capital of ant-munching seems to be Slovenia, where they can sometimes account for 25% of a bear’s diet by weight, particularly in the Spring. It shows how unpredictable bears are, because Slovenia’s beech forests are only decent for ants, whereas Sweden’s lush boreal forests are a haven. Yet Sweden’s brown bear population hardly eats any ants.
Alberta is another place of ant-loving grizzlies, contributing 45% of calories in extreme cases. The typical grizzly prefers to hack apart old dead logs with its claws, rather than scooping out underground ant nests. Carpenter ants are the favourite species, and as for other insects, brown bears love ladybirds. In the early 1980s, officials running Kootenay park in Canada had to close down the area near MacDonald every year, as grizzlies consistently returned to feast on ladybirds and Miller moths.
Any of the random grubs, beetles and worms on a rotting leg are part of a bear’s menu, although they make up a lesser proportion compared to the more heavily forest-dwelling black bear. A study in Yellowstone found that grizzlies eat small amounts of earthworms in April and May, but none at all from June onwards, when the real feeding season kicks off.
If it’s there, it’ll be eaten by a bear.
| 10 | Mothmania |
In Greece, bears eat tortoise. Japanese bears eat snakes, and in Yellowstone, bears are partial to moths. 40,000 of them a day, in fact, equivalent to 20,000 calories. The species in question is the Miller moth, or the army cutworm moth, whose body can be up to 83% fat, far outstripping a pine nut or squirrel, making them incredibly energy dense for a bear. Somehow, this body fat doesn’t turn them into a couch potato, and instead, the miller moth flies to Yellowstone’s mountain slopes every summer in their thousands, to feed off the nectar of mountain flowers.
When scientists monitored 29 seperate moth hotspots, a total of 470 grizzlies arrived to feast on them, with 220 in a single year. The number of bears positioning themselves in moth country rose sharply in the three years to 2014.
Miller moths start their lives on farmland, where they’re a serious pest. According to Yellowstone rangers, this moth obsession is good for human-bear relations, because it draws them to the mountains rather than roads where they could attack people.
At 40,000 moths per day, a hungry bear could meet a third of its energy requirements for the whole year after 1 month. Catching a moth is easier than it sounds, because when they arrive in their thousands, they immediately burrow into dark crevices in the mountain slopes, to escape the intolerable sunlight. Bears must simply arrive and dig, a trick which mothers teach to their cubs. This video is a great example, until an aggressive male grizzly arrives to spoil the party.
Leave a Reply