Captain Sanga is a male crocodile and the captain of a pirate ship who appears in flashbacks in the episode "The Coin".
As Babar recounts to Celeste, shortly after the founding of Celesteville, the nascent elephant kingdom was struck by an epidemic of sleeping sickness that threatened to wipe them out. Whilst Babar and Cornelius discovered a cure, the ingredients were only found on a small island across the sea. With Celesteville lacking any ships, the desperate king was forced to turn to the only ship he knew of that could hope to make the journey in time to save the denizens of Celesteville: Captain Sanga's pirate ship.
Sanga agreed to fulfill Babar's request, but demanded an unusual price: dividing a large gold coin into three fragments, which he shared with his first and second mates, he made Babar swear that anyone who bore one of these coin fragments could trade it in for a single favor. No matter what favor was, the King of Celesteville would have no choice but to grant it: without question, and without compromise.
Seeing no other choice, Babar immediately swore this oath. Sanga promptly fulfilled his end of the bargain, and then left, making no attempt to cash in his favor.
There was a second part to this story that Babar was initially unaware of, only learning it from Cornelius many years later. Several weeks after departing, Captain Sanga returned to Celesteville in secret, his first mate retrieving Cornelius for a medical emergency: Sanga himself was dying of the sleeping sickness, and whilst he had the ingredients for the cure, Cornelius was the only person he knew who could mix the medicine. The elderly elephant nursed the crocodile back to health, and in gratitude, Sanga gave his piece of the coin to Cornelius. Confessing that Babar's courage had impressed him, Sanga asked Cornelius to use this piece to try and protect Babar, should someone with another piece make a truly unreasonable demand. He swore Cornelius to secrecy on this, lest his crew doubt his leadership should they become aware of his giving away the coin fragment.
Sanga's fate after this is unknown. Given that his first mate would reappear in the episode "The Coin" and exchange his fragment for a ship of his own, it is possible that Sanga either died or retired from piracy at some point over the years.