It is not always the case that the predator is so dominant in terms of size. Think about the large wildcats, especially. Both the lion and tiger can and do take on prey that is many times larger than them. Lions will tackle Cape buffalo weighing 600 - 900 kilograms, while the average weight of tiger kills in Nagarahole National Park in India was 401 kilograms1. That is heavier than the heaviest tiger. However from the standpoint of survival the wildcat will prey on animals that offer the least resistance and chance of being injured during the attack. The serval is much like the domestic cat in preying on rodents in long grass using hearing as a major form of prey detection (servals have notably large ears).
The domestic cat has it easy. The mouse is the perfect meal for the domestic cat. Sometimes cats play with a mouse they are attacking, even when it has been killed. This is seen as cruel by people.
|Large black calico cat and tiny mouse - Photo by Jo and Paul's pics|
Cats don't think it terms of cruelty. There are good and reasonable reasons why both the domestic cat and the smaller wildcats play with prey before and after it has been killed.
You can read about it on this page: Domestic cat hunting.
Associated: Lion prey Kruger NP.
Note: 1 Wild Cats Of The World by the Sunquists