Hedgehog

Hedgehogs are a species that appears in the video game, comic book and television series fiction of the Sonic the Hedgehog series. Unlike the real-life species, hedgehogs in the Sonic franchise are anthropomorphic animals of said species, and many prominent characters in the Sonic franchise are hedgehogs, the most recognized of them being Sonic the Hedgehog. Several robotic copies of hedgehogs also exists, most of whom were created by Dr. Eggman in imitation of Sonic, the most famous of them being Metal Sonic.

Anatomy
Hedgehogs appear mainly as anthropomorphic animals of their namesake species with anatomy closely resembling humans' shapes, though their body proportions vary from media to media. Features they do share includes large heads, short fur on most of their bodies (excluding certain areas that differ between each individual) which is frequently brightly-colored, short muzzles, and spiky quills on their heads of varying styles, similar to human hairstyles.

Like humans, male hedgehogs have more masculine figures and female hedgehogs have more feminine curves. Also, while hedgehogs' exact height measurements remain ambiguous between each media, they appear to be about one meter tall at average.

Characteristics and Culture
Character- and culture-wise, hedgehogs are no different from humans, meaning they are sentient, intelligent, have their own unique personalities and can be either good or evil.

Powers and Abilities
Hedgehogs often (but not uniformly) possess special abilities including, but not limited to, Speed (Sonic), Strength (Amy), Telekinesis (Silver) or the ability to use Chaos Control (Shadow). It is also implied in Sonic Chronicles: The Dark Brotherhood that all hedgehogs in the games naturally possess the innate ability to move at high speeds.

Games
In the games, neither the bright colors nor special powers of the hedgehogs are explained (save for Shadow, whose abilities and color derive from the circumstances of his creation).
 * Sonic the Hedgehog
 * Amy Rose
 * Shadow the Hedgehog
 * Silver the Hedgehog
 * Sir Lancelot
 * Sir Galahad
 * Nimue, Lady of the Lake

Archie Comics
In the Archie Comics, hedgehogs falls under a category of Mobians and their bright fur colors are inherited traits. Sonic's blue pigmentation originates from his family (his parents and his uncle are also blue). That said, Amy and Rob O' the Hedge are cousins, yet one is pink and the other is green, for no discernible reason.
 * Sonic the Hedgehog
 * Bernadette Hedgehog
 * Jules Hedgehog
 * Sir Charles Hedgehog
 * Amy Rose
 * Rob O' the Hedge
 * Shadow the Hedgehog
 * Silver the Hedgehog
 * Scourge the Hedgehog
 * Rosy the Rascal
 * Manik Acorn
 * Cyborg Sonic
 * Zonic the Zone Cop

Sonic the Comic
In Sonic the Comic, most hedgehogs are brown. Sonic and Amy both were born brown, and gained their distinctive colors later due to accident and mutation.
 * Sonic the Hedgehog
 * Amy Rose
 * Bravehog
 * Old Sonic
 * Extra Life (independent 1-Up)
 * King Sonic
 * Cosmic the Hedgehog
 * Tonic the Hedgehog

Cartoons
Different variety of hedgehogs in the cartoons. In Sonic X and Sonic the Hedgehog: The Movie, Sonic's blue color is not explained; in the other cartoons, it is an inherited color except in Sonic Underground, where all his family members have their own color.

Adventures of Sonic the Hedgehog

 * Sonic the Hedgehog
 * Penelope
 * Masonic
 * Mummified Hedgehog

Merhogs
Half hedgehog, half fish mobians.
 * Merna the Merhog
 * Queen of the Merhogs
 * Merhogs of Mertopia

Sonic the Hedgehog

 * Sonic the Hedgehog
 * Sir Charles Hedgehog

Sonic Underground

 * Sonic the Hedgehog
 * Manic the Hedgehog
 * Sonia the Hedgehog
 * Queen Aleena
 * Aman-Rapi
 * Queen Sauna
 * The Royal 'Corrupt' Hedgehogs
 * Fat alternate version of Sonic as a king
 * Greedy alternate version of Manic as a king
 * Vain alternate version of Sonia as a queen
 * Luke Periwinkle

Sonic X

 * Sonic the Hedgehog
 * Amy Rose
 * Shadow the Hedgehog

Sonic Boom

 * Sonic the Hedgehog
 * Amy Rose
 * Shadow the Hedgehog