Chao

"Chao chao!"

- A common phrase a Chao would use.

A Chao (チャオ) is a species from the Sonic the Hedgehog series. Their role in the games are to be raised by the player in mini-games, similar to many virtual pets. Chao are somewhat complex: they respond to stimuli, have moods, require food and can be loving or fearful. The word Chao is a pun on Chaos, a word commonly used in the Sonic series and which is why the word remains unchanged when plural. The Chao are the good friends of Cream the Rabbit and Tikal.

Making their first appearance in Sonic Adventure for the Dreamcast (both in the plot and in a Chao-raising aspect of the game), later in Sonic Adventure 2, and further enhanced in Sonic Adventure 2: Battle, Sonic Advance and Sonic Adventure DX: Director's Cut, Chao have recently come to be a large part of the Sonic the Hedgehog franchise. Chao-raising and the main Sonic games tie together in a number of ways; items which are encountered in the main game can be used to raise Chao, collected Rings can be used to buy things for them, and several unlockable features are related to Chao. During raising, Chao have statistics: Swimming, Flying, Running, Power and Stamina, as well as a number of other things which aren't quite as obvious. These statistics can be raised through proper Chao raising, and will enable a Chao to do better in their competitions: Chao Racing and Chao Karate. Eggs other than those acquired in visiting a Chao Garden for the first time or mating are colored differently and reflect how the Chao will look. For example, a Gold Egg is solid gold in color and will hatch a solid Gold Chao. Ways of hatching them include snuggling the egg (the kindest way), throwing the egg at a wall (the Chao will obviously not like this) and of course, simply waiting for the egg to hatch on its own. When they hatch, they can be trained to have different attributes and emotional states. The Chao from Sonic Adventure 2, Sonic Adventure 2: Battle and Sonic Adventure DX can also favor "dark" and "hero" sides as well as the default "neutral" side which can lead to variations in visual evolution. Depending on the game, they take varying times to evolve.

Evolution
After one Chao year has passed (about two to three hours for GameCube versions, an hour for Dreamcast), a Chao creates a cocoon and evolve into a more mature form. It will mature into a that relates to the last stat item it got (running, swimming, power, flying or stamina) and its alignment. During this evolution, a Chao raises one grade up in the level of its type, e.g. a swimming Chao who has a grade 'B' in swimming becomes an 'A'.

Alignment is determined by how the Chao was treated before its evolution, and the three alignments are Dark, Hero, and Neutral. There are three Hero characters (Sonic, Knuckles, and Tails) and three Dark characters (Shadow, Rouge, and Dr. Eggman) in Sonic Adventure 2. Petting, holding (in which case if you have separated the characters alignment it will make it worse), or cuddling a Chao with a character makes the Chao favor the character's alignment. Attacking, throwing, stepping on a Chao, or taking its food while it is eating makes it favor the opposite alignment of the character. Every three times that a heart appears above a Chao's head and replaces the standard emotion, the Chao darkens or lightens a shade, a darker shade coinciding with becoming a Dark Chao, and vice versa; the Chao darkens or lightens a shade every time a heart appears above the Chao's head once when it's petted. A Chao's physical appearance is the chief indicator in understanding the alignment of a Chao. Dark Chao have leathery wings and a devil's tail, and are colored black, brown, and pink with a small spike ball on its head. It also has a symbol on its chest similar to Knuckles'. Hero Chao have feathery wings, a split tail, and a small halo on its head. They are colored white, blue, and gold. Neutral Chao are created by balancing contact by both Hero and Dark characters, or not paying attention to them. They are able to look like a lot of different characters. In Sonic Adventure DX: Director's Cut, due to only heroic characters being playable, the Chao instead become Hero or Dark depending on the alignment fruits it is given.

Chao will evolve a second time after one to three Chao years. However, the Chao won't go into a cocoon, and the changes are sometimes very subtle. A Chao will 'evolve' depending on which stat is the highest at the moment. However, it won't change its primary type. Like a child Chao's gradual evolution, the second evolution is not permanent, and can be changed. For example, if you had a Dark/Fly/Fly Chao and gave a lot of green Chaos Drives/Animals it would become a Dark/Fly/Running Chao. However, if you then gave it Red Chaos Drives/Animals, its appearance would change again, and it would become a Dark/Fly/Power Chao.

After about five Chao years have passed, the Chao will either reincarnate or die. If the Chao has lived a happy life, it will be surrounded by a pink cocoon, and will be reborn as an egg and hatch as a Baby Chao. However, a Chao that has been ignored and abused during its lifetime will surround itself with a gray cocoon, and vanish with the cocoon.

Besides the normal evolutions, a special Chao called the "Chaos Chao" can be created. This can be done once the selected Chao has transformed two times. During that third cycle of its life, if it is given at least one of each animal in the game and all its stats are around equal, it will become a Chaos Chao. Besides looking different than a normal Chao, the Chaos Chao has an endless lifespan, except a death through extreme character abuse (not proven). In Sonic Adventure 2, there's also the "Hero Chaos Chao", also known as the "Angel (Chaos) Chao", and "Dark Chaos Chao", also known as the "Devil (Chaos) Chao", along with the normal "Neutral Chaos Chao", also known as the "Light Chaos Chao" (shaped like Chaos) from the original Sonic Adventure. Evolution works in the same manner, except you give them one animal from either the Hero or Dark characters respectively, and that all of their stats are around equal. Along with their apparent invincibility, Chaos Chao also lack the ability to reproduce. They are probably the most difficult Chao to create. The best way to make sure you've gotten all animals is to make a checklist.

The DS Chao in Sonic Chronicles: The Dark Brotherhood do not evolve; they learn to be used as weapons.

Reproduction
After evolving, Chao gain the ability to reproduce. Chao have no gender and therefore can breed with any other adult Chao. Chao are in mating season when they sit down happily and are surrounded by a circle of flowers. While this happens twice naturally, it can also be achieved by purchasing 'Heart Fruit' from the Black Market in Sonic Adventure 2: Battle/Sonic Adventure DX and giving it to an adult Chao. Placing another Chao inside the circle may result in breeding. Most Chao are compatible; a Hero Chao can breed with a Dark Chao, and vice versa. It is believed that, to at least some degree, statistics and other characteristics are inherited. As mentioned above, Chaos Chao cannot breed.

Chao Stats
By giving a Chao small animals it will acquire some of the animal's characteristics. Besides a physical change to the Chao, this will also modify the Chao's stats based on the type of animal given. There are five types of animals in Sonic Adventure and seven in Sonic Adventure 2. They consist of Running (Green), Power (Red), Swimming (Yellow) and Flying (Purple). The fifth color, Blue, is a fairly even mixture of some or all of the other classes. The two additional types featured in Sonic Adventure 2 are Ghost (Black) and Imaginary (Gold), sometimes called Legendary. The Ghost animals raise Intelligence and Imaginary animals raise Luck (These two stats cannot be seen). The Ghost and Imaginary animals give better than average stat increases and do not lower any stats.

In Sonic Adventure 2, Chaos Drives appear. Chaos Drives are items that pop out of machines created by the military organization G.U.N. when they are destroyed. These, like the small animals, also raise your Chao's stats. These are only in Sonic Adventure 2 and the GameCube adaptation. Like the small animals, the different colors each raise a certain stat. Yellow raises swim, purple raises fly, green raises run, and red raises power.

However, neither animals nor Chaos Drives can raise a Chao's stamina, only food can. Also, a certain fruit called the Chao Fruit (bought at the Black Market) raises all stats, including Stamina, when it is given to a Chao.

Transformation
In certain games like Sonic Adventure 2 Battle (after the evolution into a Hero, Neutral, or Dark Chao), Chao go into an either pink or gray cocoon at the end of their lifespan. The pink cocoon means they're reincarnating, and the gray means they're going to die. Chaos Chao (all types) are immortal; thus, they will never enter into a cocoon once formed. A reincarnated Chao keeps all of its letter grades from its previous life as well as its skills, tools, awards, and even intelligence. Its stat levels will reset to 1, but reincarnated Chao also retain 10% of their stats totals prior to death. With enough time and effort, this enables the player to eventually maximize all stats if they're raised to lv. 99 in each lifetime.

Bonding
Chao are apparently able to bond with other life forms, from animals to characters. This allows for the Chao to gain characteristics from them, and in Sonic Chronicles: The Dark Brotherhood, enhance an ability of a character.

Sonic Adventure/DX

 * Station Square - This garden is the simplest, with a small water pool. This is also where one accesses the Chao races. It is found by entering the hotel and using the left elevator. In DX, a Black Market is added.
 * Mystic Ruins - This area is very large and complex, with stone relics and a small platform accessible by a wooden bridge, along with a waterfall. It is found by going behind Tails's laboratory and taking the mining cart in the cave. In DX, the water is slightly more shallow and the bridge has been removed.
 * Egg Carrier - An island surrounded by water. This one tends to have problems of animals leaving the game's boundaries and getting stuck. To find it, go inside the Egg Carrier and go to the door with the buttons in front. Step on the buttons in the "secret" password's order, which is "Eggman", and then go in the door and use the teleporter. In DX, the water is significantly more shallow.



Sonic Adventure 2/Battle

 * Neutral Garden - A peaceful looking Garden where the Chao Races take place in a cave called the Chao Stadium. This one is unlocked as soon as you get a Chao Key and finish the level you found it on. In Battle, there is also Chao Karate in the cave.
 * Hero Garden - Another peaceful Garden. To get this raise a Chao into a Hero Chao. It has a small castle your Chao can fly from, a fountain (that your Chao uses to swim in), and a few broken pillars. The music in the Hero Garden is different from the Chao Garden, with the same rhythm, but added sound effects to make it echo and sound comforting. Sometimes described as "Chao Heaven". In Battle, the bridge and river are missing, but the pool is bigger.
 * Dark Garden - Not as serene as the others, it has some graves and a steel fence on some of the walls. It also has a tree with a cage hanging from it where you can put your Chao (it can, however, escape), a pool of "blood", and a small island on the other side of the "blood". The music presented in the Dark Garden is very demented version of the Neutral Garden music. There is also a mountainous region outside of the actual Dark Garden, with a mountain shaped in the face of a bat or demonic creature. A Dark Chao is needed to get it. Sometimes described as "Chao Hell". In Battle, the cave and mountain area are gone.

The Chao Gardens in Sonic Adventure and Sonic Adventure 2 have the ability to send Chao to an attached VMU (Visual Memory Unit), and play with the Chao away from the Dreamcast in a game called Chao Adventure. The Chao walks on a path and is given a task. If done correctly, you are rewarded with a fruit or seed which can be taken off the VMU and back onto Sonic Adventure 2 for planting. Seeds can be planted by a Chao with a shovel and a watering can. The shovel can be won in races in Sonic Adventure 2. On Chao Adventure, you can also attach two VMUs to mate Chao, check the stats of your Chao, and name it. In Chao Adventure, the Chao doesn't age like it does in gardens. In the HD Releases of Sonic Adventure and Sonic Adventure 2, the Chao Adventure Machines are changed to the Chao Naming machine and the Chao departure Machine respectively.

Sonic Advance/Sonic Advance 2/Sonic Pinball Party
Sonic Advance, Sonic Advance 2 and Sonic Pinball Party also have a Tiny Chao Garden of its own, which is a small simple garden with a small pool that is universal to every game. There is a shop where fruit and toys can be bought for the Rings that the player has collected during gameplay, and some minigames. The Chao can be transferable between these games and Sonic Adventure DX and Sonic Adventure 2: Battle via a GameCube/ GBA link cable.

Sonic Advance 3
Also, Sonic Advance 3 has a Chao Playground, unlike a Chao Garden, it is not for raising Chao. Instead, it is an area where the hidden Chao that the player has found during gameplay are located. When all ten of the Chao in the zone are found, the player can look for keys that enable the Special Stage for that particular zone. If the Chaos Emerald is obtained for a Zone, then it will be seen floating in the Chao Playground of the Zone it was found in. The Chao Playground can be visited at any time via Factory Ring.

Shadow the Hedgehog
In Cryptic Castle, Shadow finds a room that is inhabited by many Chao. This is possibly Dr. Eggman's private Chao Garden. Cheese is hidden within the walls.

Sonic X
There is a Chao Garden in Mr. Tanaka's childhood town as seen in episode 22.

In issue 5 of the comic series, Dr. Eggman is seen having a Chao Garden in his base to raise his own unique Chao.

Sonic Chronicles
In Sonic Chronicles: The Dark Brotherhood, there is a Chao Garden where all Chao that have been found can be viewed and equipped. However, as in Sonic Advance 3, the garden is only for storing Chao, not interacting with or raising them. Taken out of the garden, however, they bond with the character they are attached to, and power them up with various effects.

Sonic Shuffle
Chao appear in Sonic Shuffle as a playable character.

Sonic Heroes
Chao appear in the bonus stages and in two Team Chaotix missions; one where they must collect a number of Chao and another where they must collect one.

Sega Superstars Tennis
Lots of Chao sit on the sidelines of the Sonic the Hedgehog stage.

Sonic Rivals
Various Chao artwork appear as some of the 150 cards.

Sonic Rivals 2
The Chao play an important role in this game's storyline. At the beginning of the story, the Chao have appeared to have gone missing and Sonic and Tails suspect that Eggman Nega (masquerading as Eggman himself) is behind the disappearance. Silver, along with Espio, in the meantime tries to hide every Chao he can find from Eggman Nega's sight because of Eggman Nega's intentions with the small creatures: he plans to feed them to a powerful beast named the 'Ifrit' which grants it invincibility and to be unleashed into Sonic's world, conquering the world with it. Later in the story, Eggman Nega reveals to Espio and Silver that he has acquired more than enough Chao kept in a secret room of a mysterious mansion to turn them into the Ifrit's meal. Despite of this, Sonic and Tails discovered the secret room before Eggman Nega does and escorted the Chao away to safety.

The Chao are featured in one of the Battle games of Sonic Rivals 2 called 'Capture the Chao' where the player has to find a route to his/her rival's base and capture the Chao there before the rival does the same to the player but the player's original Chao must still remain at the base for it to be counted. In the free mode, there are nine Chao deployed in each act of the six zones and the player have to find and collect them (similar to Sonic Advance 3) to unlock cards, there are six Chao detectors (which each is unlocked by unlocking a card) used to find them easily in each zone.

Sonic Unleashed
There is a day mission in Spagonia and one in Shamar (one of the DLC levels) that has Sonic collect ten Neutral Chao to complete the act.

Super Smash Bros. Brawl
The Chao make cameos in the cross-over game, Super Smash Bros. Brawl appearing as a collectible Trophy and Sticker.

Sonic Colors
In the DS version of the game, a mission in Tropical Resort shows Orbot and Cubot chasing a Chao that they think is an alien and Sonic has to rescue it.

Sonic Generations
Cheese is with Cream. Other Chao also appear in a side mission where the player challenges Cream in collecting Chao.

Treatment
Chao are kept happy if they are pet, fed, and generally taken good care of. If a Chao is treated well by a character, it will skip towards that character and will nuzzle next to it sometimes. It will also happily come to you when you whistle, and when held, will fidget with glee. This means that your Chao loves the player's character and in the case of the nuzzling, is asking for attention. The Chao will also jump up and down and giggle happily at your presence.

Chao abuse is a somewhat strange and negative form of Chao raising, in which one abuses their Chao. This can be done in a manner of ways, such as starving a Chao, leaving it in the water when it cannot swim, or simply inflict physical harm upon it. Chao abuse usually decreases the lifespan of the Chao, and the Chao can possibly die when it comes time to transform. Players generally abuse their Chao either because they enjoy it, or to "help" a Chao change alignment by abusing it with a character of the opposite side (Abused by a dark character to favour the hero alignment characters and vice-versa). However, mistreatment is in no way necessary in order to change a Chao's alignment, as treating them kindly with a character of the desired alignment works just as well. If a Chao is treated poorly by the character, it will usually stand and shiver in fear if the abusing character is close by, and when held, it will try to squirm out of the character's hands (this could also mean that the character haven't fed the Chao for a while if it stops fidgeting with joy). If the Chao has been particularly abused, it might run away screaming from the abuser, run up to them and attack them (this has no effect on the character), or start crying.

In the original Sonic Adventure Chao were very fragile to raise and would quickly die if a character attacks them over and over, but after the Hero/Dark aspect was introduced in Sonic Adventure 2 Chao no longer die right away but instead their personality changes and they end up hating the character that abused them (however, they will still eventually end up dying after becoming an adult).

Other Chao

 * Monotone Chao are Chao that are a single color, which will not change, even if it is evolved or given Chaos Drives/Small Animals. They can be bought at the Black Market and come in colors Pink, Purple, Red, Orange, Yellow, Lime Green, Green, Sky Blue, Blue, Brown, Black, Grey, and White. There is also a Monotone Normal, which is a Normal colored Monotone that changes color depending on the main color of the alignment and type and can only be obtained through breeding.


 * Shiny Chao are shiny versions of Monotone Chao that can also be bought at the Black Market for a higher price. If a Shiny Chao is bred with a Normal Chao, there is a chance of getting a Shiny Normal Chao, a shiny version of an ordinary Chao.


 * Jewel Chao are the Chao that can only be bought in the Tiny Chao Garden and Sonic Adventure 2's Black Market. They are very similar to Shiny Chao except that they are metallic instead of shiny and almost look like jewels. Jewel Chao come in colors Silver (White), Gold (Brown), Ruby (Pink), Sapphire (Blue), Amethyst (Purple), Emerald (Green), Garnet (Red), Aquamarine (Sky Blue), Peridot (Lime Green), Topaz (Yellow), and Onyx (black). Two of them can also be obtained in Sonic Adventure DX's Adventure Fields.

In Sonic Adventure DX: Director's Cut, a gold Chao, a black Chao, and silver Chao can be obtained. The black Chao is a Monotone Chao, the gold Chao is a Jewel Chao, and the silver Chao is a Jewel Chao as well.


 * Two-Tone Chao are unique Chao that can only be obtained by breeding a Monotone with a Normal Chao. They have a 'main' color like Monotone Chao, but also have a small blend of other colors. There is a Two-Tone version of every Monotone Chao. It can be difficult to tell whether a Chao is Two-Tone or Monotone, as there is sometimes little difference between the two. Normal Chao are also considered Two-Tone as they aren't a single color. If a Shiny Chao is bred with a Normal Chao, there is also a chance of getting a Shiny Two-Tone Chao. If you want a dark blue-and-black shiny Two-tone Chao you need a shiny dark blue Chao and a red-and-black two tone Chao. Mate them, save the game, and go back and hatch it.

White Two-Tone Chao are unique in that they look exactly like Normal Chao when they are hatched, but depending on what they evolve into, they will look much different. For example, if a White Two-Tone Chao evolves into a Neutral Run Chao, instead of being light green, it will be white with blue streaks, pink limbs and a yellow stomach.


 * Transparent Chao are unique Chao that are completely invisible except for their eyes, emotion ball, wings and medals (if any). They can be obtained by breeding a Shiny Chao with a Jewel Chao.


 * Translucent Chao are Chao that are partially see-through. Like transparent Chao, they can only be obtained by breeding a Jewel Chao with any Shiny Chao.


 * Character Chao are unique that greatly resemble three characters: Tails, Knuckles, and Amy. The Knuckles and Amy Chao are only available through Action Replay, although the Tails Chao can be obtained via Phantasy Star Online or Action Replay. They are immortal, can't breed, and aren't affected by animal parts.

Although not official Character Chao, Neutral/Run/Run, Dark/Run/Run, Neutral/Fly/Fly, Dark/Fly/None, and Neutral/Fly/Power Chao greatly resemble Sonic, Shadow, NiGHTS, Reala, and Jackle respectively.
 * Chaos Chao are chao that are immortal. These can be obtained by getting a Chao to go through two transformations, then giving it one of all 21 animals (no more, no less; no Chaos Drives ). When the Chao evolves, it will become a Chaos Chao. If it evolves neutral, it will be a Light Chao. If it evolves Hero, It will be an Angel Chao. If it evolves Dark, it will be a Devil Chao.

Cameo appearances

 * In Sonic Adventure, a poster found outside Casinopolis advertises a film called "Chao in Space". This may be a reference to Lost in Space, and the poster resembles the posters for the movie Muppets from Space.
 * In Sonic Adventure 2, posters in the City Escape stage advertise "Chao in Space 2", featuring a Hero and a Dark Chao. The poster also mentions that it is "now on DVD".
 * Also in Sonic Adventure 2, a billboard with a Chao on it can be seen beside the road in the Kart Racing stages and mini-game. The billboard reads "Drive Safety!" instead of the correct "Drive Safely!"
 * Also in SA2's City Escape, there is a Planet of the Chaos poster similar to the front cover of the 2-disc Planet of the Apes.
 * Also in SA2, a neutral Chao is playable in the 2-player shooting mode. In the GameCube version, there's also a Dark Chao who replaces Big the Cat. Despite the addition of the Dark Chao Walker, there is no playable Hero Chao, oddly enough - the neutral Chao Walker still sides with the heroes.
 * In SA2B, a Chao is unlocked as Tails' extra kart in Kart Racing after all of Tails' Missions are completed.
 * A neutral Chao is a playable, secret character in Sonic Shuffle for the Dreamcast.
 * In Sonic 06, there is a damaged poster that reveals some Dreamcast-era Chao and, although cut off, looks to be Chao in Space III. However, this is unused in the final game.
 * In Sonic Heroes, Chao appear in odd numbered Special Stages, where a Neutral Chao and a Dark Chao float in front of the characters in a hot air balloon. The Neutral one throws power orbs to help the characters, while the Dark one throws mines.
 * Also in Sonic Heroes, Team Chaotix are given several missions that consist of finding and rescuing Chao.
 * In Shadow the Hedgehog, dozens of Chao can be found frolicking in Dr. Eggman's Cryptic Castle base. They can be attacked, which makes them cry and slightly raises Shadow's "dark" meter. Cheese can be attacked, too, but once simply touched is considered to be rescued.
 * In the 2006 Sonic the Hedgehog game, a rusted Chao billboard can be seen being blown around by the tornado in Shadow's glider section of the "Crisis City" stage.
 * Also in Sonic the Hedgehog, the first rusted sign Silver uses as a platform in the first section of his "Crisis City" stage says "Chao Garden", though it is difficult to tell.
 * Also in Sonic the Hedgehog, there are several rusted signs advertising Chao In Space III, though it is difficult to tell.
 * In Phantasy Star Universe there are rare monsters called "Jao" which looks like a more vicious version of a Chao. The Phantasy Star series was also created by Sonic Team.
 * In the game Billy Hatcher and the Giant Egg, a Chao appears as an Egg Animal for the first mission in the game.
 * In Sonic Chronicles: The Dark Brotherhood, Chao are power ups.
 * In Sonic Unleashed a mission in Spagonia makes you collect ten Neutral Chao as Sonic the Hedgehog. Also, a travelling salesman by the name of Wentos in the game carries around a Chao puppet in his right hand, acting as if it has a mind of its own and occasionally talks to it.
 * In Mario & Sonic at the Olympic Winter Games, when training for the Ski Cross event, to complete training, the player must race a Chao to the goal.
 * In Sonic & Sega All-Stars Racing, Chao are seen in the audience of the Seaside Hill tracks, and as seen as a trophy.
 * Mega Man Star Force Leo, Pegasus, or Dragon versions, features a character known as Mr. Hertz that sometimes appears on the wave roads; when you talk to them, the portrait of his face resembles a Chao head.
 * A monster called PuPu in the JRPG series Final Fantasy resembles a Chao, strangely.
 * In Sonic Generations, you can see a Chao in Space III poster when Silver uses Meteor Smash.

Reception and impact
Chao and the Chao-raising system have received mixed to positive reviews. In a review of Sonic Adventure, GameSpot's Peter Bartholow stated that "[w]ith the Chao-breeding simulation and the minigames, Sonic offers much more beyond the completion of its story." IGN stated that "SA more than has the extras department covered." This enthusiasm was extended to IGN's reviews of Sonic Adventure 2, Sonic Advance, and Sonic Adventure DX: Director's Cut. GameSpot's Shane Satterfield was critical of the Chao raising feature in Sonic Adventure 2: Battle, stating that "there's little in the way of interactivity" and that "the [C]hao training aspect using the Game Boy Advance is little more than a novelty." However, GameSpy's Shane Bettenhausen praised the feature in the game, comparing Chao to Tamagotchi digital pets. GameSpot's Frank Provo noted the appeal to "those people who might only enjoy pinball in passing" that Chao brought to Sonic Pinball Party. 1UP.com's Chris Baker called the Chao feature in Sega Superstars "ultimately worthless ... but some might find it amusing." In a review of Sonic Chronicles: The Dark Brotherhood, GameSpot's Shiva Stella praised the level of strategy that the game's Chao system added. Destructoid's Jim Sterling voiced a similar opinion, although saying that Chao had been "rubbish" in previous games. In an official Sonic character poll by Sonic Team, the Chao were voted the sixth most popular characters in the series.

A Chao keychain was released as part of a Sonic X character keychain series. Between July 27 and September 8, 2002, Sega hosted events at Tokyo-based department stores to promote upcoming Sega video games. Attendees could download "Chao Mini Garden"s and exclusive Chao to their copies of Sonic Advance. Chao clothing clips, along with accessories based on other Sega characters, were available.

Chao's notability extends beyond the Sonic series and related media; Mary Jane Irwin of IGN used "Chao program" to describe Pokémon Channel in her review of the game.

Trivia
The reason for this happening may be because they were going to make a brand new model of a head with the pacifier, rather than just make a model of the pacifier by itself, and have it be put on the Chao's head like you would think it would. But, since they scrapped the pacifier, they never bothered making the Chao-pacifier combo model, so the game's using a model that doesn't exist.
 * "Chao" is pronounced like "chow", in singular and plural form.
 * Chao bear many physical similarities to the Nightopians from the NiGHTS series. This may be due to the Chao system using an advanced version of the A-life system that was originally used in NiGHTS into Dreams.
 * In the cutscenes for Sonic Adventure, Chao originally had different shaped wings, similar to those of Hero Chao. (This is because they were special cinematic models that were only used in the cutscenes, they did not appear in the Chao Garden)
 * Through a secret mission in Phantasy Star Online Episode I &amp; II, another game created by Sonic Team, it is possible to receive a "Tails Chao". This Chao resembles Tails to a great extent and cannot die or reproduce, much like a Chaos Chao.
 * On the Sonic Adventure 2 official soundtrack (Multi-Dimensional), there is an instrumental song with Chao singing (or rather making Chao noises) in the background. This song plays in Chao Kindergarten for SA2 and SA2: Battle.
 * The Dreamcast version of Sonic Adventure states that the Chao Gardens were created in protected environments. Ironically enough, it is possible to drown when playing as the character Tails in either water pool in the Egg Carrier or Mystic Ruins Chao Gardens. It is also possible to die by jumping off the cliff or throw a Chao off to make it disappear in the Mystic Ruins Garden. In the DX version, this was changed: if a character falls out of a garden by using other glitches, he or she will appear in the middle of the garden without dying.
 * Also, in the Sonic Adventure 2 Dreamcast Version, while playing as Tails in the Dark Chao Garden, going to the deepest part of the pool near the cave is deep enough for Tails to be successfully submerged in the water, causing him to eventually drown in the water. Tails is the only character who can drown because he is shorter than everyone else.
 * It is possible to move a Chao from a GameCube into a Game Boy Advance without a Sonic Advance game. This creates a temporary Tiny Chao Garden, and is useful for moving Chao between Sonic Adventure DX and Sonic Adventure 2: Battle. This garden also changes version depending on the game the GBA downloaded it from.
 * In addition, this is also useful to Clone Chao.
 * In Sonic Adventure DX, a monitor in the Station Square Chao Garden can bring up a hint menu. One of the hints is to watch the Chao's stamina bar, even though this stamina bar is from Sonic Adventure 2, and isn't in either version of Sonic Adventure.
 * Originally, a pacifier was meant to be an accessory for a Chao, but was scrapped for unknown reasons. The Pacifier can still be used by using Gameshark cheats, but it makes the Chao's head invisible.
 * The Chao appear in Sega Superstars Tennis at the Green Hill Zone court. It is possible to hit them with a tennis ball. If you manage to hit them, they bounce up and flip upside down then land on their feet.
 * Occasionally, a Chao will draw a picture of a normal Chao on the ground. If you care for your Chao a lot, it may occasionally draw a picture of your character. Sometimes they draw a cake or pizza-like picture to show that they are hungry.
 * Despite Sonic Adventure stating that Chao do not like to be in crowded groups (no more than 8), at Cryptic Castle, in Shadow the Hedgehog, there is a group of chao vastly exceeding 8. Also, in Sonic Rivals 2, Silver stated that Chao live in packs.
 * This may have been made to prevent the player from overcrowding their gardens, or having too many to raise. Another reason could be that only 8 Chao can fit into a Garden due to memory. For example, if all 3 Chao Gardens were open in Sonic Adventure 2 Battle, and the Hero Garden was full. If a ninth Chao was brought in, one of the Chao that was already in the Hero Garden would be moved to one of the other 2 gardens.
 * In the Sonic Adventure series, Chao made baby noises, and in Sonic Heroes, they could even speak small sentences, such as Cheese saying "It's Chocola Chao." But now, the only thing Chao can say are their own names, in a Pokémon-esque manner.
 * While in a Chao Garden, if there is a Chao above you for whatever reason (in the cage in the Dark Chao Garden or flying around), you can jump to hit the Chao, causing the same effect to happen if you were to throw, jump on, or attack the Chao.
 * In Sonic Chronicles, the Chao are uniquely different from the other games, meaning these Chao are rare breeds all their own. Some are, although, simply different coloration of normal Chao.
 * Some Chao are seen on posters in Sonic Generations in Speed Highway and City Escape promoting the fake movies Chao in Space and Planet of the Chaos. This is also similar to Sonic Adventure and Sonic Adventure 2; as they also displayed "Chao in Space" posters.
 * People not used to the series might mistakenly pronounce Chao as "Kao" instead of "Chow", this might be because "Chao" and "Chaos" are spelled in the exact same way (minus the "s"), and since Chaos is pronounced "Kay-Aws", it's easy to assume that Chao would be pronounced "Kay-Oh" since the "Cha" would seem like a "K".
 * During the development of Sonic Adventure, it was suggested Chao be called "Chicka Monkeys", so not to confuse players with Chaos.
 * Chao were originally meant to appear in Sonic Boom: Rise of Lyric where they would resemble small dragons.
 * Normal Chao have the Fly Type as their ability type.

Sprites
 Chao-fine.gif Chao-happy.gif Chao-pet.gif Chao-sleeping.gif Chao-sweatdrop.gif Flying Chao!.gif Chao menu.png|Sonic Rush ChaoSonicColors.png|Sonic Colors ChaoSonicColors2.png|Sonic Colors ChaoSonicColors3.png|Sonic Colors ChaoSonicColors4.png|Sonic Colors 