Care

Hamsters are rodents belonging to the subfamily Cricetinae. The subfamily contains about 24 species, classified in six or seven genera. Hamsters are crepuscular. In the wild, they burrow underground in the daylight to avoid being caught by predators. Their diet contains a variety of foods, including dried food, berries, nuts, fresh fruits and vegetables. In the wild they will eat any wheat, nuts and small bits of fruit and vegetables that they might find lying around on the ground, and will occasionally eat small insects such as small fruit flies, crickets, and meal worms. They have elongated fur-lined pouches on both sides of their heads that extend to their shoulders, which they stuff full of food to be stored, brought back to the colony or to be eaten later. Although the Golden Hamster (Mesocricetus auratus) was first described scientifically in 1839, it was not until 1930 that researchers were able to successfully breed and domesticate hamsters. Pet Syrian hamsters are descended from hamsters first found and captured in Syria by zoologist Israel  Aharoni. Hamster behaviour can vary depending on their environment, genetics, and interaction with people. Because they are easy to breed in captivity, hamsters are often used as lab animals in more economically developed countries. Hamsters have also become established as popular small house pets.

Organizations devoted to competitive breeding of guinea pigs have been formed worldwide, and many specialized breeds of guinea pig, with varying coat colors and compositions, are cultivated by breeders.Their molars are particularly suited for grinding plant matter, and grow continuously throughout the animal's life.

Most grass-eating mammals are quite large and have a long digestive tract; while guinea pigs have much longer colons than most rodents, they must also supplement their diet by coprophagy, the eating of their own feces.

However, they do not consume all their feces indiscriminately, but produce special soft pellets, called cecotropes, which recycle B vitamins, fiber, and bacteria required for proper digestio。 The cecotropes (or caecal pellets) are eaten directly from the anus, unless the guinea pig is pregnant or obese.They share this behaviour with rabbits. In geriatric boars or sows (the condition is rarer in young ones), the muscles which allow the softer pellets to be expelled from the anus for consumption can become weak.

This creates a condition known as anal impaction, which prevents the boar from redigesting cecotropes, though harder pellets may pass through the impacted mass.The condition may be temporarily alleviated by carefully expelling the impacted feces

Healthy

If handled correctly early in their life, guinea pigs become amenable to being picked up and carried, and seldom bite or scratch. They are timid explorers, and rarely attempt to escape from their cages, even when an opportunity presents itself. Guinea pigs who become familiar with their owner will whistle on the owner's approach; they will also learn to whistle in response to the rustling of plastic bags or the opening of refrigerator doors, where their food is most commonly stored.

Domesticated guinea pigs come in many breeds, which have been developed since their introduction to Europe and North America. These varieties vary in hair and color composition. The most common varieties found in pet stores are the English shorthair (also known as the American), which have a short, smooth coat, and the Abyssinian, whose coat is ruffled with cowlicks, or rosettes. Also popular among breeders are the Peruvian and the Sheltie (or Silkie), both straight longhair breeds, and the Texel, a curly longhair.


Dogs are also susceptible to parasites such as fleas, ticks, and mites, as well as hookworms, tapeworms, roundworms, and heartworms.
Dogs are highly susceptible to theobromine poisoning, typically from ingestion of chocolate. Theobromine is toxic to dogs because although the dog's metabolism is capable of breaking down the chemical, the process is so slow that even small amounts of chocolate can be fatal, especially dark chocolate.
Dogs are also vulnerable to some of the same health conditions as humans, including diabetes, dental and heart disease, epilepsy, cancer, hypothyroidism, and arthritis.

Cats are obligate carnivores: their physiology has evolved to efficiently process meat, and they have difficulty digesting plant matter.  about 20% of a cat's diet must be protein. Cats are unusually dependent on a constant supply of the amino acid arginine, a diet lacking arginine causes marked weight loss and can be rapidly fatal.

Another unusual feature is that the cat also cannot produce the amino acid taurine, with taurine deficiency causing macular degeneration, where the cat's retina slowly degenerates, causing irreversible blindness. Since cats tend to eat all of their prey, they obtain minerals by digesting animal bones and a diet composed only of meat may cause calcium deficiency.

A cat's digestive tract is also adapted to meat eating, being much shorter than that of omnivores and having low levels of several of the digestive enzymes that are needed to digest carbohydrates. These traits severely limits the cat's ability to digest and use plant-derived nutrients, as well as certain fatty acids.Despite the cat's meat-oriented physiology, several vegetarian or vegan cat foods have been marketed that are supplemented with chemically synthesized taurine and other nutrients, in attempts to produce a complete diet.

However, some of these products still fail to provide all the nutrients that cats require, and diets containing no animal products pose the risk of causing severe nutritional deficiencies.