Moles

1 Moles are small cylindrical mammals adapted to a subterranean lifestyle. They have velvety fur; tiny or invisible ears and eyes, reduced hind limbs, and short, powerful forelimbs with large paws positioned for digging. The term “mole” is especially and most properly used for true moles of the Talpidae family in the order Soricomorpha found in most parts of North America, Asia, and Europe.

2 Moles have been found to tolerate higher levels of carbon dioxide than other mammals, because their blood cells have a special and unique hemoglobin protein. Moles are able to reuse the oxygen inhaled when above ground, and as a result, are able to survive in low-oxygen environments such as underground burrows.

3 Moles have polydactyl forepaws; each has an extra thumb (also known as a prepollex) next to the regular thumb. While the mole’s other digits have multiple joints, the prepollex has a single, sickle-shaped bone which develops later and differently from the other fingers from a transformed bone in the wrist, independently evolved but similar to the giant panda’s thumb.

Rats

1 Rats are various medium sized, long-tailed rodents of the superfamily Muroidea. “True rats” are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus. Many members of other rodent genera and families are also referred to as rats, and share many characteristics with true rats.

2 Rats are typically distinguished from mice by their size. Generally, when someone discovers a large muroid rodent, its common name includes the term rat, while if it is smaller, the name includes the term mouse.

3 The best-known rat species is the black rat (Rattus rattus) and the brown rat (Rattus norvegicus). The group is generally known as the Old World rats or true rats, and originated in Asia. The common species are opportunistic survivors and often live with and near humans; therefore, they are known as commensals. They may cause substantial food losses, especially in developing countries. The average lifespan of any given rat depends on which species is being discussed, but many only live about a year due to predation.

4 Specially bred rats have been kept as pets at least since the late 19th century. Pet rats are typically variants of the species brown rat, but black rats and giant pouched rats are also known to be kept. Pet rats behave differently from their wild counter parts depending on how many generations they have been kept as pets. Pet rats do not pose any more of a health risk than pets such as cats or dogs. Tamed rats are generally friendly and can be taught to perform selected behaviors.