Ants can be great pets, if you want a pet that is constantly working on a project(other than chewing on your shoes), and does not need to be taken outside for a poo. Less a companion, more an source of fascination at their achievements, they are easy to look after, and cheap to feed.
If you want to keep ants the first thing you need is an ant farm. Almost anything can be used to house ants, but fishtanks are the best as they provide the ants with the space to set up camp, whilst providing you with easy access to all sides of their nest. Make sure seal the top so they don?t escape.
You can also buy plastic ones from toy stores, but they are often poorly made. Make sure you open the pack to see how well they are made before purchase, you don?t want ones that don?t seal or break easily, resulting in your pets escaping.
Choose a soil that opposite in colour to the ants if possible for your ant farm, dark for light coloured ants, light for dark coloured ants, its easier to watch them. Fill your farm with the soil or sand, making sure you leave at least 5 cm at the top for them to roam around. Wet the soil a little to ensure their tunnels do not collapse(dry, large grained sand is a recipe for tunnel collapses and unhappy little critters).
To stock your farm I suggest you start by just capturing a group of workers from the garden. For the more adventurous, you could dig up a nest to find the queen, that way your farm will have some longeivity. If you see an existing ant nest exploding with new royalty(the ones with wings) grab as manyh as you can and stick them in your farm. The boys won?t last long, bu the girls will likely start their own nest shortly after, Some pet shops will order in queen ants for you to start a colony.
Ants eat just about everything, but do make sure your provide them a variety. Dead insects, food scraps(think? picnic? but don?t give them too much or your will soon have a moldy smelly antfarm.
Not for everyone, but for some, ants as pets are just the ticket.