- Adult Male Grizzly Bears: Adult male grizzly bears are known to sometimes kill and consume other grizzly bears, especially if they are rivals for territory or mates.
- Humans: Humans are the primary predators of grizzly bears. Hunting, habitat destruction, and human encounters can lead to fatalities for grizzly bears. Human-caused mortality has been identified as a significant factor affecting grizzly bear populations in some areas.
- Wolves: Wolves are predators of grizzly bears, mainly targeting cubs. Although it is rare that a pack of wolves can kill an adult grizzly, grizzly cubs are susceptible to wolf predation, especially if they are separated from their mothers.
- Other Predatory Animals: Other large predators, such as cougars or wolverines, have also been known to occasionally kill and feed on grizzly bears. While such instances are relatively rare, these animals, especially if the grizzly bear is young, old, or sick, can pose a threat.
- Diseases and Parasites: Although not technically predators in the traditional sense, diseases, illnesses, and parasites can cause mortality and reduce the survival rates of grizzly bears, impacting their populations.
- Climate-related Factors: Climate-related changes can also impact grizzly bear populations and cause mortality. Extreme weather conditions, changing food availability, and shifts in habitat due to climate change can indirectly pose challenges that might lead to mortality in grizzly bears.