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A Year 5 Dark Swim/Fly+Run Chao
A Year 5 Dark Swim/Fly+Run Chao
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Chao Life-Cycle
Chao Evolution
Age & Appearance
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GameCube Engine

Age broadly describes how long a Chao has been alive, where the Chao is in its life cycle, and how close the Chao is to Reincarnation or Death. The main features of a Chao's lifecycle are its birth from an Egg, its childhood, its Evolution after which it becomes an adult Chao, its adult life, or Second Evolution, and finally the Chao's death or reincarnation.


Chao Egg

A Chao is born from its egg at level 0 in all Stats, (unless it was reincarnated) and as such begins being able to do little. A child Chao can learn all stat based skills that an adult can such as walking and swimming. Over the course of a Chao's childhood its Evolution Strength will increase, also more commonly referred to as the Chao's magnitude, making it look more and more like the evolution which it will evolve into. The Evolution Strength stat begins at 0 and will increase about every 2 minutes by 0.01666667, or 1/60 (considering how 1 Chao year is 60 clock rollovers, and every clock rollover the magnitude increases, the Chao hits it's 1st birthday when it's magnitude becomes 1 and evolves). Additionally the stat will increase by 0.005 for every bite of Fruit the Chao takes. When the Evolution Strength value reaches 1 the Chao will trigger its Evolution by sitting down and forming a Cocoon around itself. After the short amount of time in its cocoon, it will emerge as an adult Chao. The evolution will generally occur sometime around 3 hours in to a Chao's life.


After becoming an adult Chao, and being locked into its evolution, the Chao is able to mate and produce a child Chao. Animal Parts on an adult Chao take on new appearances, such as most wings becoming larger, or Dragon wings changing from pink on child Chao to purple on adult Chao. As an adult Chao ages it will go through similar gradual evolution changes that it did as a child Chao, this instance also being known as Second Evolution. Much like before the strength of these changes is based on the Evolution Strength stat, which ranges from 0 to 1.2 for adult Chao. The Evolution Strength value will increase by 0.00125, or 1/800, for every bite of fruit. The increase to the stat over time, unlike for child Chao, varies based on which Garden the Chao is in. In the Chao Garden the Chao's Evolution Strength, or Magnitude as it's more commonly known, will increase by +0.004166666884, or roughly 1/240, about every 2 minutes. In the Hero Garden, Evolution Strength increase is doubled, to +0.008333333768, or roughly 1/120. In the Dark Garden there is no increase to Evolution Strength over time- only through feeding. Due to this effect, a Chao in the Dark Garden can live its full adult life without reaching a full Second Evolution. This Garden effect is not present in SADX gardens.



There are two values for determining a Chao's lifespan, called RemainingLife1 and RemainingLife2. RL1 can not increase beyond RL2's value; if it would, it is capped at the same value. RL2 cannot exceed 9999. A Chao will die, or reincarnate, when either RL1 or RL2 values decrease to 0. There are some less common cases where reincarnation may trigger while Lifespan is above 0, the exact causes of why are not known. Since RL1 is capped to less than or equal to RL2, RL2 is the really the only relevant variable for normal Chao raising.

RL1 and RL2 are set to the same value when a Chao is born. They are set to a value greater than 3000 and less than 4000, determined by the formula:

3000 + (Lifespan grade*100)

Much like other stat grades, the grade is an integer value starting at 0 for each Chao. The upper limit for the lifespan grade is not known. Unlike other grades, lifespan grades not determined by genetics; a child Chao's parents' RL values have no bearing on the child's RL values. After reincarnation a Chao's new set of RL values will generally be set to the same values it had when first born. However, if reincarnation is triggered while the Chao has a Lifespan2 above 0 (which may happen for unknown reasons) its new lifespan will be determined by the formula:

3000 + (lifespan2/10) + (Lifespan grade*100)

For child Chao, every bite of fruit adds +3 to RL1, and +5 to RL2. For evolved Chao, every bite of fruit adds +3 to RL1. And for adult Chao, every few minutes RL2 decreases by 6 or 7. Since RL1 is capped at RL2's value, RL1 is raised during adult life through feeding, and RL2 is the only value to ever decrease, RL1 is largely irrelevant for normal Chao raising. The purpose of RL1 is unknown.

As chao ages, RL1 and RL2 both decrease at a faster rate. needs more info

An adult Chao will have roughly 29 hours of life before dying or reincarnating, assuming its RL values are 4000 when born. And, rather unintuitively, since RL2 only begins decreasing for adult Chao, an earlier evolution will decrease overall lifespan (by a fairly small amount.)

Technical Info

The "Age" at the Chao Doctor is Clock Rollovers divided by 60, where a Chao will become age 1 when it has experienced 60 Clock Rollovers, and age 2 when it has gone through 120 Clock Rollovers. Clock Rollovers increment every time the Chao "Grows" (magnitude increases, lifespan changes, etc). The Chao Manager checks timescale for 32 Chao objects every 3 frames, which means that any given Chao object gets "reached" every 96 frames. When the Chao Manager reaches an object, the "timescale counter" increases and when it reaches the timescale amount, the Chao "grows".

The timescale can vary per game, and is 120 in the SADX timescale. Thus the Chao grows every 96 frames * 120 timescale, which is 11520 frames. Considering that the game is running at 60 fps, the Chao grows every 11520 / 60 = 192 seconds, which is 3.2 minutes.

Using all this info together, a Chao year approximately lasts 60 * 3.2 minutes, or 192 minutes.