Assistant Laboratory Animal Technician (ALAT) Practice Exam

Which of the following are considered poikilothermic animals?

1. Mammals

2. Fish and reptiles

3. Birds and amphibians

4. Insects and mammals

The correct answer is: Fish and reptiles

Poikilothermic animals are those that cannot regulate their body temperature internally and instead rely on the environment to determine their body heat. Fish and reptiles are prime examples of poikilothermic animals. They adapt to the temperatures of their surroundings; for instance, reptiles will bask in the sun to increase their body heat or seek shade to cool down. Mammals, birds, and amphibians, on the other hand, are primarily endothermic (warm-blooded) and can internally regulate their body temperature to maintain stable conditions, regardless of the external environment. Therefore, the only group that clearly fits the definition of poikilothermic in this question is fish and reptiles.