If you encounter a half-eaten male lion by a dog, this usually means that the male lion has died and the dog has had the opportunity to access and eat part of its remains. In the natural environment, this situation may be caused by a variety of factors, such as a male lion dying naturally due to old age, disease, injury or other reasons, and then being discovered and eaten by dogs.

However, this is uncommon as lions are apex predators and are usually able to protect themselves from Injury to other animals. And dogs will not actively attack adult male lions.