Final answer:
The primary threats facing mammals include habitat destruction, overexploitation, invasive species, pollution, diseases, and accidental mortality. Marine mammals are especially affected by accidental mortality. Climate change is also predicted to pose a significant threat to mammals.
Step-by-step explanation:
Habitat destruction is the most widespread threat to mammals, affecting 37% of all extant and recently extinct species. Other threats include overexploitation, invasive species, pollution, diseases, and accidental mortality. Marine mammals are particularly affected by accidental mortality, with 83% of species being impacted. These threats can vary geographically and may change over time. Climate change is also predicted to become a significant threat in the future.