Exciting course announcements! Wildlife Survey Field Methods: Ungulates is now open for registrations. Limited Seats Remaining! Register here! Amazon Associates – Registration is now open! Register here. Let’s get social, join our NRTG Student Facebook group here.

An argument for the importance of reading sign

I was recently on a vacation visiting friends in northern British Columbia when my mentor took me out to a spruce tree right beside his driveway and showed me a strangely marked tree (Figure 1). He asked me if I knew what it was and it took me several seconds to recognize as it is relatively uncommon. This is a grizzly scratch. Here a bear reared up on its hind legs, reached up the tree, and dragged its formidable claws down the bark. The boars do this as they have glands between their toes which leave a scent on the tree; by reaching high they are simultaneously placing the scent high up where it will drift the farthest and also advertising to all other bears how large they are. And this was a large bear. I am 5’10” and can reach to 7’6” – this bear could slam dunk a basketball around my block. Though the sign-maker was nowhere around, this simple sign of his presence was impressive (and intimidating).

Figure 1: Grizzly scratches on spruce tree, northern BC.

So why am I writing about this apart from the cool factor? It got me thinking about bear sign and the importance of it for those of us working in bear country. Bear populations in most of the places I work and visit are healthy. Not only are they abundant, but, I believe, they are becoming more bold. I am convinced that our reduction in hunting the bruins has emboldened them and so they do not fear or avoid us as they did in the twentieth century. Incidents with bears, sometimes tragic, sometimes casual, occasionally even humorous, are on the rise. There are multiple causes of this: encroachment on habitat, conditioning to human food sources, surprising a bear on a trail, disturbing a sow with cubs, naïve and inexperienced people venturing out. But I do suspect there is also a reversion by the bear to the realization that we are weak and largely defenceless against them. They are coming to the realization, as David Quammen famously says of alpha predators, that humans “are just another flavor of meat”. I am currently reading a book from 1957, The beast that walks like a man, in which the author provides compelling evidence from First Nation oral history and early explorer journals that before the development of modern and repeating rifles, grizzly bears did attack people unprovoked. They suffered no fear of us without tough hide, large size, sharp teeth, or powerful claws. Our modern weak aversive conditioning may be insufficient to deter these impressive but dangerous animals.

Now, this blog is not intended to frighten you, gentle reader – though some fear of bears is a healthy attribute. Rather it is a reminder that they deserve our respect and honour. And most importantly our observation of their sign so that we can know when we are in their areas and where they might be. For example, the described bear scratch is a territorial marker – seeing this informs you that you are in an area the bears will defend. The message sent is crystal clear: it says “I am this big… if you are smaller stay out of my way.” But other sign – quite common when you open your eyes to it – also advertises the bears presence and when it was in the area.

  • Scat: One of the most well-known signs of bear. When you find this, check it for freshness. Is it soft and malleable (fresh)? Hard and dry (old)? An old trick to age it is to flip the scat over (using a stick – never touch scat of any animal with bare hands). If the grass is still green under it, it is fresh. Dead grass suggests it has blocked the sunlight for at least a couple of days. In addition, examine the contents. What has the bear been eating? Berries? Animals? If berries, you may want to avoid large berry patches as these are where the bear is feeding and they tend to be thick brush into which you may wander blindly into the feeding bear.
  • Tracks: Another obvious sign most people are familiar with. Here you want to determine if you are on a grizzly trail or that of a black bear. Size alone doesn’t do it because a small grizzly will have the same size track as a medium or large black bear. Instead, using the front track, draw a line across the top of the pad from the bottom of the inside toe; that is, the thumb (Figure 2). If the pinky toe falls on or below that line, it is a black bear; if above the line it is a grizzly. If the claws show in the track, for example in mud, the grizzlies claws are much farther ahead of the toes than a black bear. A blackie’s claws are actually quite short (typically less than 5 cm long); a grizzly, in contrast, has much larger (5-10 cm long) and threatening claws.

Figure 2: Illustration of discrimination of black bear track from grizzly by drawing a line connecting the base of the thumb pad across the top of the pad and determining where the pinky falls. These are right front feet so the centreline of the bear is to the left of the track.

  • Hair: During the molt periods of spring and fall, particularly the spring when the bear is shedding its winter dress, it will frequently leave patches of loose hair on trees, branches and bark, barbwire fences, etc. The coat is worn, loose, and being sloughed off as the sleek summer coat comes in. It is also itchy and so the bear scratches himself against objects to relieve the irritation. In so doing it can leave considerable hair on its scratching post. Loose and available hair like this does not remain in place for long in the forest; rodents come and seize it to line burrows, birds take it for nesting, strong winds blow it off the branches. So shed hair on trees or fences not only tells us bears are present but also that they have likely been there recently.
  • Dens: These can be difficult to find or they can be obvious. When a large bear digs a den it moves a tremendous amount of earth to the mouth of the burrow. These are difficult to mistake for anything else. But not all bears do this. They may take over and enlarge a wolf den, which will show less modification, only an increase in size. Or they may use natural openings and caverns and not dig dens. The variety of subterranean cavities used by bears precludes simple identification. I have only once or twice found a den that I would unambiguously say was bear – more usual I see openings that could be used by a bear but whether it actually houses the animal is less clear (without crawling into it, which has never seemed to me like a good idea).
  • Torn up logs: Despite the bears fearsome reputation both black and grizzlies eat surprisingly little meat. They have reverted so far from the ‘true predator’ that they have lost their carnassial teeth – the identifying character defining Carnivora. They are omnivores with the occasional taste for meat. As part of this catholic diet, they include insects on the menu and to access these are happy to tear into decaying logs, stumps, and trees. In so doing they leave woody debris spread across an area and a semi-destroyed piece of wood. This can sometimes be confused with aggressive bark destruction by woodpeckers, but when a bear tears something apart, material tends to be flung over a larger area and the wood fragments include large pieces as well as small. Woodpecker destruction tends to leave the woody dregs around the base of the tree where the fragments have simply fallen down, and the fragments are of more consistent and smaller size.

Bears are very good at hiding and avoiding us. Even the grizzly. This is a bear that was hunted by the massive prehistoric bears – that is a sobering thought; this huge carnivore was itself prey for larger cousins – and so it is quite adept at moving silently and remaining motionless to avoid detection. Seeing bears in thick timber often does not happen until the observer is uncomfortably close to the animal. Paying attention to the sign of bears around us while going though our activities in bear country, can help us understand their abundance and their use of the landscape we are sharing with them.

Alone, these various signs left by bears are interesting. But it is in putting them together that we begin to form a clearer picture of bruins in the area. What is the abundance or density of tracks or scat you are seeing? What is its freshness? What are they eating at this time of year? Based on this are there certain areas they are more likely to be? Shed hair suggests a winter den nearby or recent movement by a newly emerged bear through the area…  The art of trailcraft lies not only in identifying sign but, more importantly, inferring its meaning and integrating the various forms together.

NRTG offers Wildlife Survey Field Methods: Carnivores which includes greater detail on bears, reading their sign, and survey methods for them. In addition, we recommend anyone working in bear country take available training in their area on bear safety and safe working in bear country. 

Sean Mitchell


1 Quammen, D. 2004. Monster of God: the man eating predator in the jungles of history and the mind. WW Norton.

2 Two of the most famous and dramatic cases are the close escape of William Clarke of the famous Lewis and Clarke expedition while in Montana. It came very near to simply being called The Lewis Expedition. And a second example is the triple mauling of the ex-Pawnee captive, ex-impressed pirate, turned mountain man Hugh Glass. The movie “The Revenant” is (poorly) based on the mauling of Glass for whom the bear returned twice more after the initial mauling, and this while Glass’s compatriots were shooting it with their flintlocks.