Bear Series, Part One: A Bear's Sense of Smell

October 01, 2014 Posted by: JG - Park Ranger (Yosemite Valley)
When you visit Yosemite National Park, you are likely being smelled by at least one of Yosemite's black bears (Ursus americanus). Whether you're in Yosemite Valley, at Glacier Point, or at the top of Mt. Lyell, you are within the range of a bear's sense of smell. This fact can be attributed to the size of Yosemite's area, the size of the park's bear population, and the bears' amazing sense of smell. 

Yosemite National Park has an area of 1,169 square miles;in comparison, the State of Rhode Island is 1,214 square miles. Park biologists believe that Yosemite's population of black bears is between 300 and 500 bears. This means, assuming an even distribution of Yosemite's bears, there's one bear every 2.3 to 3.9 square miles. A black bear's sense of smell can easily be measured in miles. 

Looking at a black bear's head, it's obvious that they have a very large nose. The area inside a black bear's nose, called the nasal mucosa, is 100 times greater than ours. This large nose results in an excellent sense of smell! Even bloodhounds, dogs so famous for their sense of smell that they're used to track missing people, don't smell as well a black bear. It is estimated that black bears' sense of smell is about seven times greater than a bloodhound's. 

Black bear seen at Hetch Hetchy
A black bear's sense of smell is so good that it's difficult to measure. Bears are commonly thought to have the keenest sense of smell in the animal kingdom, and estimates of the range of their sense of smell vary widely. Conservative estimates of a black bear's sense of smell state that a black bear can smell a food source from over a mile away, while other sources claim a black bear can smell food from over two miles away. A personal account from "The Great Bear Almanac" describes a black bear in California traveling "upwind three miles in a straight line to reach the carcass of a dead deer." More generous estimates place a black bear's sense of smell between 18 and 20 miles, which may sound extreme, until you learn that polar bears, the black bear's cousin, have been known to follow seals for up to 40 miles. 

In summary, though it's difficult to measure just how far a black bear can smell, a range of a few miles isn't unrealistic. With 300 to 500 bears roaming Yosemite at any given time, it's more than likely that at least one of them are smelling you at all times. So the next time you're in Yosemite, take a minute to stop and think about everything you smell, and what also might be smelling you.  

Nature Scene, JG




3 Comments Comments icon

  1. June 24, 2015 at 09:49
     

    I just returned home from Juneau Alaska visiting relatives.my cousin has a house on the beach one morning we woke up to find a brown bear about 30 feet in front of us on the beach my cousin did not believe me because he said there's no brown bears in Juneau after a little research he was correct there are no brown bears they're called cinnamon black bears because of their color.we were there for 13 days ate a lot of good food accumulated a lot of trash well my cousin sent me a photograph yesterday of a cinnamon bear right in his front yard.the bear had gotten into his garage turn over the trash can and trash was everywhere throughout the garage my cousin at first thought it was a black crow but after seeing the bear he realized that the crows coulda turned over the heavy trash can and in fact it was the bear.so tonight I googled how far can a bear smell after reading this article it all makes sense now. my wife and I slept in the guest house on the property it's a small log cabin with no refrigerator it was 75 through 82 degrees while we were there so one night I started to set a key lime pie outside to keep cold thank God I didn't.Lol

     
  2. June 24, 2015 at 09:48
     

    I just returned home from Juneau Alaska visiting relatives.my cousin has a house on the beach one morning we woke up to find a brown bear about 30 feet in front of us on the beach my cousin did not believe me because he said there's no brown bears in Juneau after a little research he was correct there are no brown bears they're called cinnamon black bears because of their color.we were there for 13 days ate a lot of good food accumulated a lot of trash well my cousin sent me a photograph yesterday of a cinnamon bear right in his front yard.the bear had gotten into his garage turn over the trash can and trash was everywhere throughout the garage my cousin at first thought it was a black crow but after seeing the bear he realized that the crows coulda turned over the heavy trash can and in fact it was the bear.so tonight I googled how far can a bear smell after reading this article it all makes sense now. my wife and I slept in the guest house on the property it's a small log cabin with no refrigerator it was 75 through 82 degrees while we were there so one night I started to set a key lime pie outside to keep cold thank God I didn't.Lol

     
  3. Ken
    December 24, 2014 at 11:39
     

    From our family's frequent bear sightings in all parts of the park, year after year, it sure seems like 300-500 bears is low estimate for their population!

     
 
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