List how many pets there are in the world?

It's impossible to give an exact number of pets in the world. There's no global registry or census that tracks every pet.

However, we can look at some estimates:

* Dogs: Around 900 million dogs worldwide.

* Cats: Estimates range from 600 million to 1 billion cats worldwide.

* Other pets: This includes fish, birds, reptiles, rodents, and more. It's hard to estimate this category, but it's likely to be quite large.

Therefore, it's safe to say there are billions of pets in the world.