This chapter provides more detailed descriptions of common laboratory animals in biomedical research, including anatomy, physiology, management, and husbandry, commonly used in biomedical studies. It gives a brief note on the characteristics and laboratory management of macaques. The laboratory mouse is assigned to the genus Mus, subfamily Murinae, family Muridae, and order Rodentia. The genetic background of the mouse is one of the most studied of any animal used in research. Mice are utilized in more conventional laboratory techniques where knockout mutations of known genes of interest are created in order to study the effects of the gene in the resultant phenotype. The laboratory hamster is domesticated from wild animals. Gerbils have a very important anatomic character in that the posterior communicating artery of Willis' circle is deficient. The skeletal system of guinea pigs contains the skull, torso, limb, and bones. They are strictly herbivores, have transversely inclined molars, and the incisors are arcuated and extend to the jaw.