Why do cold-blooded animals have no fat layer under their skin?

Explanation

### Step-by-Step Solution:

1. **Definition of Cold-Blooded Animals**: Cold-blooded animals, also known as ectotherms, are organisms that cannot internally regulate their body temperature. Instead, their body temperature fluctuates with the temperature of their environment.

2. **Temperature Regulation**: These animals adapt their body temperature according to the surrounding environment. For instance, when the external temperature rises, their body temperature rises as well, and vice versa when the temperature drops.

3. **Dormancy in Harsh Conditions**: During extreme environmental conditions, particularly in winter, cold-blooded animals enter a state of dormancy. This state is often referred to as hibernation or winter sleep, where their metabolic processes slow down significantly.

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