Assistant Laboratory Animal Technician (ALAT) Practice Exam

What is the average weight of a typical newborn rat?

1. 2-3 grams

2. 5-6 grams

3. 10-12 grams

4. 15-20 grams

The correct answer is: 5-6 grams

The average weight of a typical newborn rat is around 5-6 grams. This weight reflects the physiological characteristics of rat pups at birth, including their size and stage of development. Newborn rats are altricial, meaning they are born relatively underdeveloped and rely heavily on their mother for nourishment and care during the early stages of life. In considering the other weight ranges, the lower option of 2-3 grams may underestimate the typical newborn weight, as newborn rats generally weigh more than this range. Similarly, the higher ranges of 10-12 grams and 15-20 grams exceed the average weight of newborn rats, as they are not typically that heavy at birth. This information aligns with standard laboratory practices and provides guidelines for monitoring the health and growth of neonatal rats.