Students observe rats, noting details of their growth, weighing them and measuring body proportions. Prior training and experience in capture, restraint and handling must occur to ensure that the rats are restrained for the shortest possible period. Only rats that are accustomed to handling should be used for measurements. Routine weighing and measurements should always take place to ensure rats do not become overweight as this is a common problem with caged rats.

Palatability

For small animals such as mice and rats, the only dietary effect that should be investigated is the palatability of different foods. As rats are small in size, it is unacceptable to vary or restrict the quantity or quality of the feed provided.