Because pets cannot communicate in spoken languages like humans can, they often behave strangely either because they cannot control themselves, or because they are trying to convey a problem to the people who live with them. Animal behavior can provide important clues about the health of a pet, and if you notice your pet acting oddly, you may want to consider consulting a veterinarian, especially if the behavior is prolonged or potentially dangerous. Make sure to keep an eye on the animals in your life so that you can gauge whether or not a behavior is unusual, and also handle your pets frequently so that you will be aware of any strange growths, cuts, or sores.
The most common cause for strange pet behavior is stress. Stress can be caused by moving, the introduction of another pet, or the introduction of another human into the household. Animals will also react to the emotional state of the individuals they live with, so if you are stressed, your animals probably will be too. Stressed animals may pace, nip, or engage in other compulsive behavior. The best cure for this type of behavior is time. Make sure that the animal has a safe and familiar space to retreat to, and do not attempt to force the pet into any activities. If the animal's eating and drinking habits change, or the behavior grows worse rather than better, consider phoning the vet.
Another source for strange animal behavior is medical problems. If an animal suddenly becomes incontinent or has issues with the litter box, for example, it may be an indicator of digestive or urinary tract problems. Cats, especially, are prone to kidney stones, which may cause them to urinate in strange places. Rather than punishing an animal that is not using the bathroom correctly, you should take it to a veterinarian for a checkup. You may also notice an animal scooting around on the floor after using the bathroom, which is an indicator of impacted anal glands which need to be expressed.
When animals start to bite, claw, or engage in other aggressive behavior, this can also indicate a medical problem. Take note of when the animal acts out: it may be linked to a touch in a sensitive region, for example. In some cases, an animal may apparently randomly develop aggressive habits which should be treated by an animal behaviorist. Aggressive behavior may also be linked to abuse, so observe an animal which is acting aggressively with care and see if there is a common link between the people the animal acts out towards, such as men or people wearing a particular color.
Issues with eating and drinking are usually strongly linked to a medical problem such as indigestion, dental ill health, or cancer. In some cases, a pet may be reluctant to eat because it is depressed. A pet will also avoid food that is tainted, so if you have just opened a new container of food or are using very old pet food, you may want to purchase a fresh supply. You should also change a pet's diet slowly, rather than all at once, mixing new food with the old so that the animal develops a taste for it. Keep an eye on how your pet eats, and if the animal starts to lose weight or drink excessive amounts of water, take it in for veterinary care.