How to return a generic object in c# create objects and implement interface

interface IAnimal
{
    void Breathe();
}

class Dog : IAnimal
{
    public void Breathe()
    {
        Console.WriteLine("I'm breathing");
    }
}

class Cat : IAnimal
{
    public void Breathe()
    {
        Console.WriteLine("I'm breathing");
    }
}

class Program
{
    static void Main(string[] args)
    {
        IAnimal dog = GetAnimal(args[0]);
        dog.Breathe();
        IAnimal cat = GetAnimal(args[0]);
        cat.Breathe();
        Console.ReadLine();
    }

    private static IAnimal GetAnimal(string animal)
    {
        if (animal == "dog")
        {
            return new Dog();
        }
        return new Cat();
    }
}