Although killer whales and blue whales are both whales, there is still a big difference in body size between them. The body length of killer whales is generally 7-8 meters. Even the strongest male killer whales will not exceed 10 meters in length and weigh about 5.5 tons. As the largest animal in the world, the blue whale can reach 30 meters long, that is, the length of four killer whales, and weighs 150-180 tons. This difference in size makes it difficult for killer whales to take advantage even if they attack in groups.

As a predator, killer whales are very fast, but although blue whales are big and heavy, their speed is not slow either. Usually, the speed is 20 kilometers per hour, but they can reach 50 kilometers per hour when sprinting. Killer whales usually have a speed of 45 kilometers per hour, but they can't keep this speed for a long time. After swimming for 10 minutes, their speed will drop, leaving only 25 kilometers per hour in half an hour. Therefore, they are very close in speed, and killer whales are not very good at chasing and intercepting.

There are still many creatures in the ocean. Besides huge whales, there are smaller dolphins, sea lions, seals, walruses, etc. It is more cost-effective for killer whales to hunt these animals. Although they can leave wounds on blue whales, it is still difficult to really kill blue whales. Therefore, if they fail to win their prey after a long attack, they often give up their targets and look for more suitable prey instead.