Leopards are known for killing prey for survival. Leopards are amongst several predators that will kill extra prey and drag them off for a later feeding or to bring back to their young. However, it is also known that Leopards will kill their prey of livestock
Household cats are well known to be, playful, lovable, and most love to be snuggled. Cats are among the list that will kill for fun because they love catching, then pawing, and playing with a mouse until it is dead.
The Bluefish is an aggressive predator of the ocean that will kill just for the fun of it. Its diet ranges from squid to small fish; however, it will kill other fish and leave them untouched just because it can. Bluefish are very territorial and will even bite a human.
Dolphins are one of the animals that are so smart that they can be trained to do all sorts of tricks. They are also one of the most brutal killers of the water. Dolphins have been known to kill porpoises by beating them to death.
Spotted Hyenas usually hunt in packs and are very territorial. The pack will kill other animals to protect their food sources such as lionesses, lion cubs, and even other hyenas. There are even reports back in the '60s of spotted hyenas attacking a group of gazelles.
We all know that lions are a predator who will kill anything they can eat; however, it is also known that lions will kill birds such as Doves just for the thrill of it, much like the house cat with its small prey.
Cuckoo birds are born natural killers. As soon as the eggs hatch, they get rid of the host eggs by sending them over the edge of the nest, and then they wait to be taken care of by the host bird.
Don't let the sweetness of the name fool you. Honey Badgers are ruthless and love to kill more than what they need to survive for fun. It has been reported that Honey badgers will enter a henhouse or the like and kill many chickens while only eating a few.