3 Reasons Why Using Bright Lights to Deter a Bear is a Bad Idea

Brown bear on a rock

If you come across a bear while out in the woods, or even your backyard, your first instinct is to get the heck out of there ASAP, right?

While running for the hills, you might reach for the first thing in your backpack (which in this case is a flashlight) which may make you feel safe.

BUT… the thing is – as good as lights are for detecting bears, over time, bears learn that lights are simply lights and are not so good at deterring them.

Don’t get us wrong, lights are still really great to have on your property, especially lights such as a motion-activated light that will automatically turn on once it senses motion.

Even more so, taking a flashlight with you near sundown is still an excellent idea, however, just know that lights are not fool-proof, or in this case, bear-proof, and are just not great at deterring bears, especially in the long term.

Side note – something like bear spray is a much better option than any light or even a whistle – in fact, we have a whole article dedicated to why whistles don’t work well either to scare bears.

When it’s all said and done, keep on reading for the 3 reasons why lights don’t work to deter bears.

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Reason 1: Lights Aren’t Effective at Startling Bears

Camping in the mountains. Moon night light

Before getting too deep into this, I just want to say that I think it’s an excellent idea to take a long-range tactical flashlight with you out in the woods at sundown.

Having a Long-Range Tactical Flashlight will let you spot a bear (or any other animal) from far away. This will allow you to spot any animal in your area from a good deal away and let you adjust your course accordingly.

That being said, those same flashlights aren’t very useful in actually startling or deterring a bear.

The theory is that these tactical flashlights are extremely bright and will cause confusion for the bear. However, this is not the case.

Bears aren’t typically scared of bright lights because bears naturally have no negative association with bright light and don’t see it as a threat.

In theory, a bear could be startled by a bright light when flashed in its eyes for the first time. However, it greatly depends on the bear’s previous association with bright lights – which can be varied, to say the least.

This situational dependency makes bright lights really not all that effective against startling bears, due to their unreliability.

If you want to learn more about bears and how they react in certain situations, you can click here for an article I wrote that goes more in-depth on the topic.

Reason 2: Lights May Confuse Bears and Not Deter Them

Brown bear (Ursus arctos) looks out of its den in the woods under a large rock in winter

Depending on the type of bear, bright lights may cause a bear to charge at you due to some species being more aggressive than others.

Specifically, I’m talking about the possibility of a grizzly bear mistakingly thinking your prey because you’re waving a tactical flashlight around and the bear has no idea what to make of it.

Grizzly bears are known to be the more aggressive species of a bear compared to black bears, which are easily startled – in fact, humans, in general, can startle bears and you should check out our other article to learn more about it!

If They’re Protecting Their Cubs, Bears Can See The Light As A Threat

Grizzly bears are often mostly aggressive when they’re attempting to protect their cubs.

Grizzly bears are extremely protective of their cubs. If they see a bright light or another object that they don’t recognize that could be deemed as a threat, then the bear will more than likely do what her instincts tell her.

Conversely, a black bear may be startled and run away if you try to shine a bright light on it due to them being less aggressive than grizzly bears.

Tying this back to the bears and association message, bears aren’t generally startled by bright lights, but that’s mainly due to their previous experience in dealing with them.

BUT, you can never be so sure because it all depends on the type of bear you run into, and what that bear’s previous experience with the bright light seems to be. Unfortunately, you have no way of knowing this information prior.

This overlaps with the bear’s previous experience with bright lights, but everything points to it being a bad idea to depend on a bright tactical light or even a motion sensor light to deter bears.

Reason 3: Motion Sensor Lights Won’t Keep Bears Away Long Term

Motion Flood LED Light. Installing Motion Detector Lighting. Close up on Motion Sensor. Deter Bear

Given the above information, motion sensor lights really won’t do much to keep bears away from your backyard.

If a bear walks into your backyard and gets blasted by a bright motion sensor light for the first time, then it’s unpredictable to tell what the bear will do.

It may get deterred or keep going depending on its previous experiences with random, bright lights.

Once the bear learns that the light won’t harm it, then the bear won’t be wondering or afraid of what happens when it gets shined by the bright motion sensor light. This is a psychological process called habituation.

The only real added benefit of having a motion sensor light to keep bears away is that you’ll be able to see and tell when a bear comes onto your property.

That being said, I think there is some real value to having a motion sensor light on your property solely to be able to see what exactly is in your backyard at night.

Use Motion Sensors For Safety, Only!

Having that motion sensor light adds an added layer of safety that will be extremely useful when you have to go outside your house at night time.

The last thing you would want to see while taking out the garbage at night is a bear rummaging through your trash cans 5 feet in front of you because you didn’t have a light outside to help spot it.

In short, invest in a motion sensor light for the added safety of spotting a bear, but not for deterring it.

The same can be said for any tactical flashlights. Invest in these to detect the animals and not deter them, as the results are unpredictable for that.

And the reality is, if you are seeing a lot of bears lately near your home – you may be attracting them without realizing it!

If that’s the case make sure to head on over to our article about scents that may attract bears, and how to repel them!


  1. Herrero, S. (1972). Aspects of evolution and adaptation in American black bears (Ursus americanus Pallas) and brown and grizzly bears (U. arctos Linne.) of North America. Bears: Their biology and management, 221-231. 
  2. Herrero, S. (1972). Aspects of evolution and adaptation in American black bears (Ursus americanus Pallas) and brown and grizzly bears (U. arctos Linne.) of North America. Bears: Their biology and management, 221-231. 
  3. Herrero, S. (1972). Aspects of evolution and adaptation in American black bears (Ursus americanus Pallas) and brown and grizzly bears (U. arctos Linne.) of North America. Bears: Their biology and management, 221-231. 
  4. Groves, P. M., & Thompson, R. F. (1970). Habituation: a dual-process theory. Psychological review77(5), 419. 
  5. Hughson, D. L., Darby, N. W., & Dungan, J. D. (2010). Comparison of motion-activated cameras for wildlife investigations. California Fish and Game96(2), 101-109. 
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