Hello bihunsedap."Have" is used in two different ways. When you make questions or negatives, you have to know the difference.
1. The first use is as the main verb - "Dogs have fur", "I had a car."
To make
any simple present or simple past main verb into a negative, or to ask a question, you add "do" or "don't" (or "did"/"didn't"). For the negative, sometimes you can add 'no' to the noun.
I eat eggs.
Do you eat eggs?
I don't eat eggs. (I eat no eggs)
He ate the apple.
Did he eat the apple?
He didn't eat the apple.
Do dogs have fur?
Do caterpillars have fur?
Caterpillars don't have fur. (Caterpillars have no fur.)
I had a car.
Did you have a car?
I didn't have a car. (I had no car.)2.The other use of "have" is as an auxiliary verb, to make 'perfect' tenses. "I have eaten the apple", "They have gone away", "They have had their dinner."
To make
any perfect or past perfect verb into a negative, or to ask a question, you reverse the subject and "have" or just add "not".
You have eaten the apple.
Have you eaten the apple?
You haven't eaten the apple.
They have had their dinner.
Have they had their dinner?
They haven't had their dinner.****************
Your sentences are of type #1. "Have" is the main verb, not an auxiliary.
Dogs have fur.
Do caterpillars have fur?
Caterpillars don't have fur.
Caterpillars have no fur.[image not available]
