Which is the only species of snake that is known to deliberately build a nest to guard and incubate its eggs?

Introduction / Context:
Most snakes lay their eggs in hidden spots or give birth to live young without building any elaborate structure. However, one snake species is famous for showing unusually advanced parental care by actually constructing a nest. This question asks you to identify which snake is known as the only species that builds a nest to protect and incubate its eggs.

Given Data / Assumptions:

• The question focuses on nest building behaviour in snakes.
• We are looking for a species that actively arranges leaves and debris to form a nest.
• The options include King Cobra, Anaconda, Python, Viper, and Rat snake.
• Only one of these snakes is widely documented as constructing a nest for its eggs.

Concept / Approach:
Parental care in reptiles is usually limited, but the King Cobra is a striking exception. Female King Cobras gather leaves, grass, and other material to build a mound like nest. They lay their eggs inside and may guard the nest for some time, defending it from threats. Other snakes may choose suitable sites or coil around eggs, but they do not build nests in this active, structured way. So the correct approach is to recall which snake is described in wildlife documentaries and textbooks as the nest building snake, and that is the King Cobra.

Step-by-Step Solution:
Step 1: Recall that nest building is rare among snakes and is a hallmark of one iconic species.Step 2: King Cobra females are often shown collecting leaves and debris into a pile to form a nest.Step 3: Pythons may brood their eggs by coiling around them, but they usually do not build a separate nest structure from leaves.Step 4: Anacondas, vipers, and rat snakes rely on natural shelters or other strategies rather than nest construction.Step 5: Therefore, the only snake that is properly described as building a nest is the King Cobra.

Verification / Alternative check:
Herpetology references and nature programmes frequently mention that the King Cobra is unique among snakes for its nest building and maternal guarding behaviour. No other species in the options has this behaviour described in a standard way. This consistent information verifies that King Cobra is the correct answer.

Why Other Options Are Wrong:
Option B: Anacondas are large aquatic snakes that give birth to live young and do not build nests.Option C: Many pythons brood their eggs but do not construct a nest of leaves and debris.Option D: Vipers typically give birth to live young or deposit eggs in sheltered areas, not in constructed nests.Option E: Rat snakes lay eggs in hidden spots but do not show elaborate nest building.

Common Pitfalls:
Students sometimes confuse egg brooding with nest building and may think pythons build nests because they coil around eggs. Another mistake is assuming that all snakes show similar reproductive behaviour. To avoid confusion, remember that nest building in the sense of constructing a mound from materials is unique and is a famous characteristic of the King Cobra.

Final Answer:
The correct answer is King Cobra.