Beast Keeper and Egg Cave allow users to adopt virtual pets, including dragons, as of 2015. Because both are browser games, players do not need to install any applications to play them. Both games have fairly active user bases with over two million pets created collectively.
Even though registration for either game does not cost money, both of them also offer paid premium content. The websites sell in-game currency to players, who can then use that currency to buy additional content. However, it is also possible to earn in-game money on Beast Keeper by inviting friends and sharing custom skins. Egg Cave players can only acquire in-game currency with real money.
Beast Keeper also lets players customize and train their pets as well as research pet genetics and develop better breeds. Pets age in time but do not die of old age. An in-game year lasts three days in real life. Pregnancy takes one and childhood takes three real days.
In comparison, Egg Cave lets players adopt pets by acquiring eggs. Eggs need clicks to hatch. As such, Egg Cave encourages players to put links to the eggs on their personal websites, forum signatures and profiles on other websites. As opposed to Beast Keeper, pets can die in Egg Cave. A pet that is below level 2000 dies if not fed, so users must feed their pets daily.