Which of the following is an example of a circannual rhythm?

• A. Mosquitoes are most active at dawn and dusk.
• B. Just as the sun sets, bats leave the cave in large swarms.
• C. Fiddler crabs exhibit courtship behavior based on the phase of the moon.
• D. In the heat of the day, most of the mammals at the zoo rest in the shade.
• E. Every spring robins gather in the park to build nests and reproduce.

Answer: (E)

Verified step by step guidance

1. Understand the concept of circannual rhythms: These are biological processes that occur on a yearly cycle, often influenced by seasonal changes.
2. Identify the key characteristics of circannual rhythms: They typically involve behaviors or physiological changes that align with the seasons, such as migration, hibernation, or reproduction.
3. Analyze each option provided in the problem: Determine whether the behavior described is influenced by a yearly cycle or a different type of rhythm.
4. Evaluate the option 'Every spring robins gather in the park to build nests and reproduce': This behavior is linked to the spring season, indicating a yearly cycle, which is characteristic of a circannual rhythm.
5. Conclude that the correct example of a circannual rhythm is the behavior of robins gathering every spring to build nests and reproduce, as it aligns with the definition of a circannual rhythm.