Pokémon species data structure (Generation IV)

The Pokémon species data structure is a 44-byte structure that determines all information inherent to a Pokémon species, such as base stats, types, Egg Groups, and EV yield. Every Pokémon species in the Generation IV has a data structure stored in the game's ROM.
==Notes==
Base Stats 	Base Stats	Base Stats
 	type 	offset
Base HP 	byte 	0
Base Attack 	byte 	1
Base Defense 	byte 	2
Base Speed 	byte 	3
Base Sp. Attack 	byte 	4
Base Sp. Defense	byte 	5
Type 1 	byte 	6
Type 2 	byte 	7
Catch rate 	byte 	8
Base Exp. yield 	byte 	9
Effort yield 	word 	10
Item 1 	word 	12
Item 2 	word 	14
Gender 	byte 	16
Egg cycles 	byte 	17
Base friendship 	byte 	18
Level-up type 	byte 	19
Egg Group 1 	byte 	20
Egg Group 2 	byte 	21
Ability 1 	byte 	22
Ability 2 	byte 	23
Safari Zone rate	byte 	24
Color 	byte 	25
Padding 	word 	26
TM and HM flags 	13 bytes 	28
Padding 	3 bytes 	41
Missing from this structure are moves known at Level 1, level-up moves, and evolutions, which are stored elsewhere.
===Types===
The types are associated with the following values:
{| style="text-align:center"	Value	Type
0	 	
1	 	
2	 	
3	 	
4	 	
5	 	
If the Pokémon only has one type, both Type 1 and Type 2 will be set to the same value.
===Effort yield===
Each stat is assigned two bits to determine how many EVs the Pokémon will give in that stat. The last 4 bits in the byte are empty (0).
Bits 	Stat
0-1 	HP
2-3 	Attack
4-5 	Defense
6-7 	Speed
8-9 	Special Attack
10-11	Special Defense
===Items===
If an item is assigned to Item 1, the Pokémon will have a 50% chance of having that item when encountered in the wild. An item assigned to Item 2 will have a 5% chance of being held. If both Item 1 and Item 2 are the same, then the Pokémon will always be holding that item when it is encountered.
===Gender===
This value determines the chance that a Pokémon will be male or female. If the species is not all male, all female, or gender unknown, then this value is compared to the lowest byte of a Pokémon's personality value to determine its gender.
Value	Gender
0 	Always male
1-253	Mixed /
254 	Always female
255 	Gender unknown
===Level-up Type===
The following values correspond to the different growth rates a Pokémon can have:
Value	Growth 	Lv100 Exp
0 	Medium Fast	1,000,000
1 	Erratic 	600,000
2 	Fluctuating	1,640,000
3 	Medium Slow	1,059,860
4 	Fast 	800,000
5 	Slow 	1,250,000
===Egg Groups===
The following values correspond to the different Egg Groups a Pokémon can belong to:
{| style="text-align:center"	Value	Type
1	 	
2	 	
3	 	
4	 	
5	 	
For Pokémon only in a single Egg Group, both entries are the same value.
===Safari Zone rate===
This value determines the rate at which the Pokémon will flee when encountered in the Safari Zone. Only Pokémon that appear in the Safari Zone have this value set.
===Color===
Color is used in the Pokémon Storage System box thumbnails. The following values correspond to the different possible colors:
{| style="text-align:center"	Value 	Type
0	Red 	
1	Blue 	
2	Yellow	
3	Green 	
4	Black 	
For some Pokémon species, the bit 7 (the most significant bit) of this field is also 1. The reason for this is unclear.
=== TMs ===
The TMs which a Pokémon can learn are stored as a bunch of flags. Starting from the LSB of the first byte, and ending with the MSB of the last byte. The HMs are treated as TMs 93-100. The remaining 4 bits in the last byte are all 0.
===Fingerprint===
Below is a sample of the data for the first Pokémon species data structures.
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 // ?????????? (used for unknown/glitch Pokémon)
2D 31 31 2D 41 41 0C 03 2D 40 00 01 00 00 00 00 1F 14 46 03 01 07 41 00 00 03 00 00 20 07 35 84 08 1E 10 02 20 24 66 92 02 00 00 00 // BULBASAUR
3C 3E 3F 3C 50 50 0C 03 2D 8D 00 05 00 00 00 00 1F 14 46 03 01 07 41 00 00 03 00 00 20 07 35 84 08 1E 10 02 20 24 66 92 02 00 00 00 // IVYSAUR
50 52 53 50 64 64 0C 03 2D D0 00 06 00 00 00 00 1F 14 46 03 01 07 41 00 00 03 00 00 30 47 35 86 08 1E 10 02 28 24 66 92 0A 00 00 00 // VENUSAUR
27 34 2B 41 3C 32 0A 0A 2D 41 40 00 00 00 00 00 1F 14 46 03 01 0E 42 00 00 00 00 00 23 06 51 CC E4 1E 82 12 01 A4 46 92 02 00 00 00 // CHARMANDER
3A 40 3A 50 50 41 0A 0A 2D 8E 40 01 00 00 00 00 1F 14 46 03 01 0E 42 00 00 00 00 00 23 06 51 CC E4 1E 82 12 01 A4 46 92 02 00 00 00 // CHARMELEON
4E 54 4E 64 6D 55 0A 02 2D D1 00 03 00 00 00 00 1F 14 46 03 01 0E 42 00 00 00 00 00 33 46 71 CE E4 5E 8E 16 09 A4 46 B2 02 00 00 00 // CHARIZARD
2C 30 41 2B 32 40 0B 0B 2D 42 10 00 00 00 00 00 1F 14 46 03 01 02 43 00 00 01 00 00 65 32 53 CC 40 1E C0 02 00 22 46 C2 07 00 00 00 // SQUIRTLE
3B 3F 50 3A 41 50 0B 0B 2D 8F 10 04 00 00 00 00 1F 14 46 03 01 02 43 00 00 01 00 00 65 32 53 CC 40 1E C0 02 00 22 46 C2 07 00 00 00 // WARTORTLE
4F 53 64 4E 55 69 0B 0B 2D D2 00 0C 00 00 00 00 1F 14 46 03 01 02 43 00 00 01 00 00 75 72 53 CE 40 1E C8 02 88 A2 46 C6 0F 00 00 00 // BLASTOISE
...
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