Which of the following is an important adaptation of animals to the cold climate ?

Options

A. Thin layer of body fat
B. Aestivation
C. Increased tendency to shiver
D. Reduced surface area to volumen ratio

Answer

To determine the important adaptation of animals to cold climates, we will analyze the provided options step by step:

### Step-by-Step Solution:

1. **Understanding the Importance of Temperature**:
- Temperature is a crucial abiotic factor that affects the metabolism and physiology of living organisms. In cold climates, animals must adapt to maintain their body temperature and metabolic functions.

2. **Evaluating Each Option**:
- **Option A: Thin layer of body fat**:
- A thin layer of body fat is not effective for insulation. A thick layer of subcutaneous fat is necessary to prevent heat loss in cold environments. Therefore, this adaptation is not suitable for survival in cold climates.

- **Option B: Estivation**:
- Estivation is a state of dormancy that occurs during hot, dry periods, not cold climates. It is a mechanism to escape heat-related stress, making this option irrelevant for cold adaptation.

- **Option C: Increased tendency to shiver**:
- Shivering generates heat through muscle activity, which can help maintain body temperature in cold conditions. This is indeed a valid adaptation for surviving in cold climates.

- **Option D: Reduced surface area to volume ratio**:
- A reduced surface area to volume ratio is characteristic of larger animals. This adaptation helps minimize heat loss, as larger animals retain heat more effectively. This is why smaller animals are less common in polar regions.

3. **Conclusion**:
- While both shivering (Option C) and reduced surface area to volume ratio (Option D) are adaptations to cold climates, the latter is a more significant and widespread adaptation among animals in cold environments. Therefore, the correct answer is **Option D: Reduced surface area to volume ratio**.