A majority of dogs have/has long tails.

[toway]

I have a question on how to use verbs in sentences like:

'A majority of dogs have long tails.'

Is it right to use have or should I change it for has because of 'majority',
that is a singular noun, especially when this fact is gained by the article 'a' before this word?

 

[entangledbank]

Definitely 'have'. At least in BrE. It's the only possibility, because only the dogs have tails.* Even omitting the dogs, you say that the majority have long tails. It's a quantifying word like 'lot', 'number', whose number is always ignored: Some dogs have short tails, but a lot have long tails.

* That makes it different from some other group words: if a group of dogs is/are attacking me, then it's true both that the dogs are attacking me and that the group is attacking me. A group can attack, but a majority can't have a tail.

 

[owlman5]

We have other threads on this topic, Toway. If you type "have" and "has" in the search window at the top of the page, you will find many of them. Here are a couple of old threads to get you started:

Collective nouns the School board <has, have>
Collective nouns - has/have - is/are

 

[toway]

Thank you very much, entangledbank and owlman5!

 

[Cagey]

Here are a couple of previous threads that discuss 'majority' specifically, though in different contexts.
Collective nouns - the majority <is, are> ... ?
Collective nouns - the majority <is, are> ... ?