How to filter items from collection based on type stored in variable

Question

I have the following hierarchy:

class Animal

class Dog : Animal

class Cat : Animal

I have a List<Animal> collection and want to make a method that will return all cats or all dogs. However I can't figure out how to filter the list elements based on a type variable. So like this:

int AnimalsOfType(Type animalType)
{
    // Gives error "animalType is a variable but is used like a type".
    return animals.OfType<animalType>().Count;
}

Answer 1

using System.Linq;

int AnimalsOfType(Type animalType)
{
    return animals.Count(a => a.GetType() == animalType);
}