This document provides information about guinea pigs, hamsters, and rabbits as experimental animals. It discusses their biological characteristics, handling techniques, uses in research, and methods of injection and blood collection. Guinea pigs are herbivorous and ideal models for studying various diseases. Hamsters have cheek pouches and are used for transplant and virus research. Rabbits are docile, have simple cardiac tissues, and are widely used in pharmaceutical and toxicology testing. Proper animal handling and use of appropriate injection sites and needle sizes are emphasized.