Killer whale parasites include tapeworms, roundworms, and flukes. Whales in general may suffer from viral, bacterial, and fungal infections. In addition, they may develop stomach ulcers, skin diseases, and tumors. Hodgkin's disease has been seen in killer whales and severe atherosclerosis of the coronary arteries was found in a stranded specimen. Killer whales are top predators in the sea.
Healthy adults have no natural predators, but sharks prey on older, younger, or ill killer whales.
D. Human interaction. Coastal killer whales are more likely to be affected by pollution, competition with humans for limited stocks of fish, and other environmental factors. On rare occasions, killer whales strand along the shoreline. Why this happens is largely unknown. One theory behind this is that killer whales accidentally strand when they chase prey into shallow waters.