Big cats are very aggressive, and will sprint and chase down their prey, this can range from mobs as small as ants, to as large asdeer. This also includes the player. If a big cat is attacked by another mob, it will fight back. Like bears, big cats will attack other mobs when hungry. Once a big cat has made a kill, it will be satisfied and will not be aggressive until it is hungry again. Tamed big cats won't attack each other or other mobs, unless another mob attacks it first.
Rapid breathing (tachypnea) is a respiratory disorder characterised by abnormal breathing that is rapid and shallow. It is caused by a reduced level of oxygen, mechanical disorders (where the lungs aren’t able to expand as they should, usually due to a build-up of fluid in or around the lungs), and physiological disorders in which the cat’s respiratory centre in the brain is over stimulated.