Does the word elephant need a capital letter?

No, the word "elephant" does not need a capital letter unless it is the first word of a sentence or part of a proper noun.

For example:

* Correct: Elephants are large mammals.

* Incorrect: Elephants are large Mammals.

* Correct: The African Elephant is the largest land mammal.

* Incorrect: The African elephant is the largest land mammal.