Whales—a.k.a. players who spend a great deal on in-app purchases—bring in the majority of revenue for the free-to-play (F2P) mobile game market, despite there being fewer of them to support a game. As mobile games evolve, so does the definition of  “whale.”

“Most game developers think of whales as their top spenders, but depending on the genre or objective of the game, this could be defined differently,” said Ben Chen, SVP and GM of developer relations at Tapjoy.

Chen referred to casual games that primarily monetize through ads instead of in-app purchases, so they focus their marketing efforts on driving user engagement. These games place higher value on user retention, defining ‘whales’ by the number of sessions and time in-app than overall spend.

DeltaDNA CEO Mark Robinson also sees the term evolving. He says the standard definition of a whale is someone who has a lifetime spend of more than $100, but that number is probably too low nowadays, and maintaining spend has become more important. A better definition for 2018 is someone who spends more than $100 per month on a game.

“Most publishers these days care about month-on-month spend rather than a flat amount in a lifetime,” said Robinson. “That is why so many older games release very niche content in a bid to keep their highest-level players playing longer.”

Robinson added that by playing longer and spending small amounts per session, rather than dropping a large amount all at once, lower spenders can eventually become whales. But not all paying players want the same things from their games.

“Some will spend for a competitive edge while others will do more for cosmetic reasons,” Robinson explained. “However, the spending patterns of these are different—players only spending to win or progress faster will burn out quickly while those that are engrossed in the game and want to customise the experience are more sustainable.”

Whales can also be divided into subcategories. In December, DeltaDNA released a study on how gender impacts gameplay and found that on average, women spend 44 percent more on than men on mobile games, specifically puzzle and casino games, suggesting that women are more invested in the platform.

Robinson said that women tend to be attracted to aesthetics, preferring games with gender-neutral art and design across all genres, rather than ones that are very masculine-oriented, such as those that only have male characters to embody or feature scantily clad women.

He also said that older gamers also make up a large fraction of the mobile gaming community, but this audience seems almost exclusively interested in very casual puzzle games and social casino apps.

The fast growth of mobile gaming not only redefines what a whale is, but brings into question whether a system where the vast majority of revenues are brought in by a minority of players is sustainable.

Robinson believes that the current monetization systems are sustainable, but they may not be the best ways forward.

“Games are under a lot of scrutiny for exploiting gambling mechanics which have sustained the casino industry for years,” he explained. “There is no reason why these would stop working, since casinos have been around and profitable for a long time. But in the long run, this may give F2P a stigma it can’t shake.”

Chen says as casual games grow in popularity, more developers are turning more toward ad-based monetization to drive revenue. While there will always be successful core titles that are sustained primarily through purchases, the model doesn’t work as well for very extremely casual games.

“For these kinds of titles, user engagement matters more than anything,” said Chen. “Each time you get your users to open the app and watch a single video, you drive incremental revenue. Plus, developers are becoming more sophisticated about where and when to promote video ads, and the ad products themselves are becoming more engaging, like with playables (streaming demos) or videos with interactive end cards. All of this helps developers more broadly monetize their audience and drive incremental revenue from every user.”