Some of the top adopt-a-pet games are Foo Pets, Egg Cave and Virtual Pets. These games range from games meant to help teach kids to be responsible for their pets to ones geared towards older players who are looking for more of a challenge. Foo Pets is extremely popular: it has been online since 2007 according to foopets.com.
Foo Pets was created by a veterinarian and is geared towards children who do not have a pet yet or their parents may be thinking of getting them one in the near future, as stated on the Foopets website. The site is made to be child friendly and has a parent page that allows parents to view information about the site and its content. Users can adopt up to 20 pets for free, but if they or their parents join the club on the site they can adopt up to 60 pets.
Egg Cave is a site geared toward older players and has over 90,000 users on the site. The site works a bit differently from other adoptable sites because it works with other sites in order to hatch the eggs. As the users share the link to their eggs, the clicks add up and hatch to reveal their new pet. This site is free as well and has a forum where users can interact and chat.