This is a common story, an owner has a dog, that is very playful and never aggressive. Then one day out of the blue the dog bites the owner, attacks him. And the sad ending of the story, the dog is given away or killed. Humans are so blind that they always blame the animal, and are always shocked – how could this happened ? They even go over the edge “we had a beast under our roof”. The truth is, animals are unpredictable and can have better or worse days, just like humans. This may be considered as personification of animals, but it goes beyond doubt that animals can feel, they can be happy, scared, sad. They never attack without reason, even if the reason may be not understandable for humans. Besides, humans are far worse. They quarrel with each other, shout at their offspring, hit each other in rage or anger. From our point of view humans are scary, noisy creatures walking on two paws, and they are a threat. If every human who acts in rage were to put to sleep like the poor animals who just had a bad mood or act according to their instincts (hunting instinct is something all animals have, it is the driving force to survival, it may be dormant but it never fades, and humans should understand that), the world population would decrease by half or maybe more. If humans can act unpredictably and its generally accepted (here I omit all the human psychos and other criminals) why can’t animals ?
Note: the only exception would be animals that have rabies, then they are dangerous and act without reason. But its not like animals want to have that sickness, it just happens sometimes.