Cats panting with their mouths open may be caused by stress reactions, high ambient temperatures, respiratory diseases or heart diseases, etc. First of all, when a cat is frightened or changes its environment, it will cause a stress reaction, which is manifested by symptoms such as shortness of breath and opening its mouth to gasp. Secondly, high temperature weather may also cause cats to have high body temperature and appear panting symptoms. In addition, if the cat has been diagnosed with respiratory disease or heart disease, these diseases may also cause symptoms such as difficulty breathing and panting with the mouth open. Therefore, if you find that your cat has symptoms such as frequent shortness of breath, mouth opening and panting, you should seek medical treatment in time.

1. Stress response

Since cats are timid and suspicious by nature, after being frightened, they can easily cause stress reactions, such as mouth breathing, shortness of breath, and difficulty breathing. For example, suddenly changing to a new environment, hearing huge noises or other unknown influences, etc. If this is the case, the owner needs to take some measures in time to alleviate the cat's severe fear, such as gently stroking the cat, putting some familiar items for the cat, etc.

　2. The ambient temperature is too high

Since cats’ sweat glands are underdeveloped, it is difficult for cats to dissipate heat through perspiration. Therefore, when the surrounding environment temperature is too high, cats often exhibit heat dissipation behaviors such as sticking out their tongues, opening their mouths and panting. In this case, the owner should move the cat to a cooler place in time and provide enough drinking water to help the cat cool down and relieve discomfort. In addition, owners can also set up a well-ventilated environment indoors and control indoor temperature and humidity to keep cats comfortable and healthy.

3. Suffering from respiratory diseases

When a cat suffers from a respiratory disease, the airway is blocked or other reasons lead to poor air flow, and the cat will have difficulty breathing. In order for the body to obtain enough oxygen, the cat will open its mouth and pant to increase the amount of air intake. Therefore, if you find that your cat often gasps with its mouth open, you need to take it to the pet hospital for examination and treatment of respiratory diseases in time.

　4. Suffering from heart disease

For cats with heart disease, it is very likely that there will be blood circulation problems, which will lead to systemic hypoxia, which is manifested by mouth breathing. At the same time, heart disease may also lead to complications such as pulmonary edema and pleural effusion. These conditions can also cause cats to have difficulty breathing and require prompt treatment. Therefore, if the cat shows symptoms such as frequent shortness of breath, mouth opening and panting, you must take it to the pet hospital for examination and treatment for heart disease in time.