Bears primarily rely on their sense of smell to find food and mates, and they can detect certain scents from several miles away. For instance, they can smell carcasses from a considerable distance, allowing them to locate food sources. However, the ability to smell blood from miles away is not a scientifically supported claim.
The sense of smell in bears is highly developed, and they have olfactory receptors that are far more sensitive than humans. They can differentiate between different scents and detect very faint odors. This keen sense of smell helps them navigate their environment, locate prey, and avoid potential threats.
Bears use their sense of smell in combination with other senses such as hearing and sight to gather information about their surroundings. While their sense of smell is remarkable, it is important to note that there are limitations to their olfactory capabilities.