During the course of a Pokémon's development, under certain circumstances specific to that Pokémon's species, it may evolve (Japanese: 進化 shinka) into a different Pokémon. This change is not merely physical, however, as Pokémon of a higher evolutionary stage have different (and usually more powerful) base stats than their predecessors, may have different moves that can be learned, and sometimes change their types, though usually at least one of the types of the previous form is preserved. Other statistics, such as nature and EVs, as well as alternate coloration, are preserved. It is similar to metamorphosis.

Professor Elm and Professor Rowan are the leading experts in Pokémon evolution. According to the latter's research, over 90% of all Pokémon are connected to at least one other through evolution. Rowan is currently investigating whether evolution is a form of maturity in Pokémon, and looking at the implications this process has on legendary Pokémon, which don't evolve.

Evolution families

An evolution family is a group of Pokémon who will all, if bred with Ditto or a Pokémon in the same Egg Group, make a Pokémon Egg that will hatch into the same Pokémon, excluding baby Pokémon. This also means that the most basic form has the potential to become any of the rest of the family, although it will ultimately be able to follow only one evolutionary path.

Stages of evolution

Pokémon can be divided into different evolutionary stages, based on where they appear in their evolution family. All Pokémon fall into one of four groups: baby Pokémon, unevolved Pokémon, first-evolution Pokémon, and second-evolution Pokémon.

Due to the fact that no evolution family contains both a baby Pokémon and a second-evolution Pokémon, many regard baby Pokémon as the most basic form, while moving their evolved counterparts one level higher. For example, originally, Pikachu was regarded as an unevolved Pokémon, however, with the release of Pichu in Generation II, many now consider it to be more on par with Pokémon like Charmeleon, though its TCG classification remains the same.

Two-evolution families

Perhaps the most well-known types of evolution families are those that feature two separate evolutionary events in the Pokémon's development. Indeed, this type of evolution family is what all of the starter Pokémon in the main series are a part of (excluding the starter Pikachu in Pokémon Yellow, as Pichu did not yet exist and it could not be evolved into Raichu), as well as all pseudo-legendary Pokémon. An example of this type of evolution family is below.

Lowest Trigger

Level 30
Middle Trigger

Level 55

One-evolution families

By far the most common type of evolution family, these families are based in a Pokémon that will only ever evolve once in its development. About one third of all Pokémon that would later get a baby form were part of this kind of evolution family before their baby form was revealed. An example of this type of evolution family is below.

Lowest Trigger

Level 20

Pokémon that do not evolve

The least common type of evolution family, of course, is that in which no evolutionary event takes place, meaning that it is made up of only one member. Many of the Pokémon that have no evolutionary relatives are, of course, legendary Pokémon. Many Pokémon that cannot evolve are also novelty Pokémon such as Smeargle and Ditto for example. However, there are still 56 other Pokémon that do not evolve. Below is a list of all non-legendary Pokémon that do not evolve.

Gen I Gen II Gen III Gen IV Gen V
083MS Farfetch'd 201MS Unown
115MS Kangaskhan 203MS Girafarig
127MS Pinsir 225MS Delibird
128MS Tauros 211MS Qwilfish
131MS Lapras 213MS Shuckle
132MS Ditto 214MS Heracross
142MS Aerodactyl  

Not belonging to an evolutionary family is not indicative of strength, or a lack thereof. Some Pokémon, such as Pinsir and Skarmory, are comparable to fully evolved Pokémon while others, like Luvdisc and Pachirisu, are more comparable to unevolved Pokémon. Often this indicates a Pokémon's possibility to be eligible for future new evolutions or pre-evolutions.

Branch evolution families

Several families, while also one- and two-evolution families, are also branch evolution families. What this means is that there is a split in the evolutionary line at some point so that even though two Pokémon of the same species evolve the same amount of times, they can become one of two or more entirely different creatures. Eevee is the best-known example of this, evolving seven different ways depending on the method used. An example of this type of evolution family is below.

Lowest Trigger

Level 25
Middle Trigger

Water Stone


King's Rock

A major difference between the final forms of an evolution family with a branch in evolution is in the way that their base stats line up. There are many opposing evolutions, with one focusing in one specific stat, the other focusing in a separate stat, and both having the same total stats. This is especially obvious in the Eeveelutions, who each have exactly the same base stats, though organized differently.

A listing of the stat focuses is below.

Basic form Evolutions Types Difference
043MS Oddish 045MS Vileplume Grass Poison Special Attack is 100, Special Defense is 90
182MS Bellossom Grass Special Defense is 100, Special Attack is 90
060MS Poliwag 062MS Poliwrath Water Fighting Defense is 20 higher, Attack is 10 higher
186MS Politoed Water Special Attack is 20 higher, Special Defense is 10 higher
079MS Slowpoke 080MS Slowbro Water Psychic Defense is 110, Special Defense is 80
199MS Slowking Water Psychic Special Defense is 110, Defense is 80
133MS Eevee 134MS Vaporeon Water Highest stat is HP
135MS Jolteon Electric Highest stat is Speed
136MS Flareon Fire Highest stat is Attack
196MS Espeon Psychic Highest stat is Special Attack
197MS Umbreon Dark Highest stat is Special Defense
470MS Leafeon Grass Highest stat is Defense
471MS Glaceon Ice Highest stat is Special Attack
236MS Tyrogue 106MS Hitmonlee Fighting Large difference between Attack and Defense
107MS Hitmonchan Fighting Speed lower than Defense, Attack and Defense more equal
237MS Hitmontop Fighting Attack and Defense equal, Speed at minimum

Methods of evolution

The various triggers for a Pokémon's evolution are almost as varied as the Pokémon themselves, and some Pokémon have a unique evolution method. The most common of them is evolution by leveling up at or above a certain level. Other methods include the following:

  • leveling up when friendship has reached a high level
  • leveling up while holding an item
  • leveling up while knowing a certain move
  • leveling up in a certain location
  • trading the Pokémon
  • trading the Pokémon while holding an item
  • using an evolutionary stone on it.

Additionally, holding an Everstone prevents a Pokémon from evolving.

Pokémon that can evolve into more than one Pokémon will usually have the ways in which the evolution is activated being slightly similar, such as having both be by evolutionary stone or by holding an item and trading. Closely-related Pokémon, such as Nidoran♀ and Nidoran♂, will also have very similar, if not identical, evolution methods.

Some Pokémon have different evolutions depending on their gender. Also, there have been situations in which the current party must be configured in a specific manner for some Pokémon to evolve. So far, only two Pokémon need to have these special requirements.

See also

Pokémon training
CatchingNicknameBattlesEvolutionTrading (Outsiders) • BreedingReleasing
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