Which of the following conditions causes aestivation in animals?

1. Analyze the question The question asks which environmental condition triggers aestivation. The key is knowing what aestivation means.

2. Explain the concept

• Aestivation (also spelled estivation) is a state of dormancy or inactivity that animals enter during hot, dry periods. It helps them survive when water is scarce and temperatures are high.
• Hibernation is the opposite: dormancy during cold winter conditions.

Examples of aestivation:

• Lungfish (e.g., the African lungfish, Protopterus) bury themselves in mud and secrete a mucus cocoon when rivers and ponds dry up.
• Snails seal their shell openings during dry spells.
• Some amphibians (frogs and toads) burrow underground in the dry season.

During aestivation, metabolism slows greatly, and the animal lives on stored food reserves until water returns.

3. Solution: test each option

• A. Wind: Wind does not trigger dormancy. Eliminated.
• B. Drought: Drought means prolonged dry conditions with water shortage and heat. This is exactly what causes aestivation. ✔
• C. Rain: Rain ends aestivation, because animals become active again when water returns. Eliminated.
• D. Cold: Cold causes hibernation, not aestivation. Eliminated.

4. Answer The correct option is B. Drought.

5. Exam tip Remember the letters: Aestivation = Arid (hot and dry), while Hibernation = Harmattan or cold (winter). If you see "summer, heat, dry season, drought" with dormancy, think aestivation. If you see "winter, cold," think hibernation.