It’s definitely not the easiest time of the year when you’re female dog is in heat. You have to have her on a leash at all times, don’t let her get near male dogs, dog boarding or holiday care usually won’t take them and so on. Another question you might have is if you can take her camping with you. Even with all the precautions taken, could it be that the odor of her bleeding might attract bears?
Myth about menstruating women
As livesience points out, there has been a myth going around about menstruating women attracting bears. This myth was caused by an incident in 1967, because 2 women were attacked by a bear. One had her period and the other one carried tampons. However, this really is just a myth. In a study performed in 1991 researchers exposed black bears (the most common in the US) to used tampons and menstruating women. None of the bears showed any interest in neither. They are far more attracted to food. It might be different for polar bears, though. They are attracted to the smell of seals. Since used tampons can have a similar strong smell, they might confuse it. But polar bears seem to just consume about anything that gets in their way. Apparently, they drank beer 66 % of the time while only eating used tampons 13 % of the time. Probably just too drunk to even see what they’re eating…
Bears’ sense of smell
According to sectionhiker bears’ sense of smell is 2’100 times better than ours. This means that they can smell you, your dog, your food, literally anything, from miles away. This is why it is generally recommended not to take your dog to bear country. Even though there is lots of evidence of (even small) dogs chasing bears away, it can also be the opposite. Barking dogs can agitate bears and they might come to chase your dog and you down. This can be different if your dog is used to seeing wild animals and is very well behaved. But in general, it’s just a risk for your dog and for you.
So what mostly attracts bears is the smell of food and dogs that chase them down. That will make them really angry.
However, I haven’t found any evidence that a female dog has attracted bears just because she was in heat. Bears will surely not be attracted by the heat of a dog for mating reasons. They might be attracted because bears learnt that dogs are around people and around people there is food. But then they would probably just as well be able to smell the people or the food in the first place. But just being in heat has no effect on the attraction of bears.
She might, however, attract more closely related animals, such as wolves, coyotes and foxes. And if you’re staying on a camping ground, there will surely be other male dogs very much interested in her!
There is no evidence that a dog in heat attracts bears in a different way than any dog or human would do. Be aware of other wild animals, more closely related to dogs, though. Coyotes and wolves can mate with a house dog and there seem to be evidence that they are also attracted by a female dog in heat.