Alolan Eggs: The Rattata Shuffle

Recently, the Silph Research Group published the results of our research on the rarity tiers of the new Alolan Pokémon. No more than 3 days after the initial results were published, some sneaky Alolan Rattata began to appear in newly gifted eggs, reshuffling the tiers!

Once again, the Silph Research Group’s most experienced researcher-walkers set out to document this new Pokémon. After hatching over 500 fresh 7-km Alolan Eggs, we proudly present the new rarity tiers for these exotic Pokémon varieties:

Hatch Rate Pokémon Rarity Tier Hatch Rate
27.6%    Uncommon 8/29
27.6% Uncommon 8/29
27.6% Uncommon 8/29
13.8% Rare 4/29
3.4% Hyper-Rare 1/29


Eagle-eyed travelers will quickly notice that in these new tiers for Alolan eggs, the Common rarity has vanished¹. Alolan Meowth was bumped down to the Uncommon tier to join Alolan Sandshrew and Rattata. This has the net effect of keeping the probability of hatching an Alolan Sandshrew, Grimer, and Vulpix constant, despite the additional species!

Once again, the newly adjusted tiers remain consistent with the system that the Silph Research Group had previously uncovered. This means that we can continue to ascertain the exact probability of hatching the various Alolan forms.

Alolan Rattata’s addition to eggs has certainly caused some controversy, but knowing that this change has had little impact on the other species may act as some small comfort to Meowth-weary hatchers. Rest assured, that elusive snow-white Vulpix is no further away!

Until next time, The Silph Research Group will continue to traverse the roads and trails of the world in pursuit of the next big Pokémon discovery. We hope to see you out there too, travelers!

– Scientist WoodWose –

P.S. Thanks (again) to Scientist Titleist12 for running the numbers on our growing Alolan dataset!

¹This rarity tier set is indistinguishable from a 16/16/16/8/2 weighting; however, we use the 8/8/8/4/1 weightings because it more closely matches the previous rarity tiers for Alolan Eggs.