killer whales belong to the top predators, that is, the top of the food chain in their environment. Usually, the animals at the top of the food chain are scarce, because they don't have enough food to feed themselves, so the number is not large. In addition, there are some external reasons that lead to the decrease of its population. For example, killer whales may run aground, or be disturbed by noise and biological pollution, which will lead to their death or even close to endangered.

1. Trapped bay: If killer whales are trapped in coastal lagoons or narrow bays and accidentally run aground, they will die, which is the main cause of their death except human reasons. This situation is also inevitable, and some of them are even related to human activities.

2. Noise disturbance: Noise disturbance also has certain influence on killer whales. Although noise can't kill killer whales directly, it can destroy their activities, especially when hunting. Because killer whales use echolocation, when interference signals appear, they can't accurately judge their position, and sometimes they even crash into ships and die.

3. Biological contamination: Biological contamination also threatens the health of killer whales. These pollutions are usually caused by human beings. Due to human activities, antibiotics and pathogens are brought into the ocean, which leads to the threat of killer whales, which may have fatal or non-fatal effects on them.