They may look like alien monsters, but they are some of the most successful life forms on Earth. They have been around for over 100 million years, surviving extinction events like the one that killed off the dinosaurs, and they have colonised every landmass except Antarctica. They are found in every garden, and many homes. They are the ants. Ants are incredibly varied and they can be as small as a pinhead or as large as a golf ball and incredibly numerous. One hectare of land in the Amazon rain forest can contain up to 10 million ants. Globally, there could be as many as a thousand trillion ants. Together, they outweigh all of the humans on the planet.