_Cats_.—I have already described the actions of a cat (fig. 9), when feeling savage and not terrified. She assumes a crouching attitude and occasionally protrudes her fore-feet, with the claws exserted ready for striking. The tail is extended, being curled or lashed from side to side. The hair is not erected—at least it was not so in the few cases observed by me. The ears are drawn closely backwards and the teeth are shown. Low savage growls are uttered. We can understand why the attitude assumed by a cat when preparing to fight with another cat, or in any way greatly irritated, is so widely different from that of a dog approaching another dog with hostile intentions; for the cat uses her fore-feet for striking, and this renders a crouching position convenient or necessary. She is also much more accustomed than a dog to lie concealed and suddenly spring on her prey. No cause can be assigned with certainty for the tail being lashed or curled from side to side. This habit is common to many other animals—for instance, to the puma, when prepared to spring;[506] but it is not common to dogs, or to foxes, as I infer from Mr. St. John’s account of a fox lying in wait and seizing a hare. We have already seen that some kinds of lizards and various snakes, when excited, rapidly vibrate the tips of their tails. It would appear as if, under strong excitement, there existed an uncontrollable desire for movement of some kind, owing to nerve-force being freely liberated from the excited sensorium; and that as the tail is left free, and as its movement does not disturb the general position of the body, it is curled or lashed about.