Legend of korra season 2 episode 5
During her youth, she met and tamed a female polar bear dog, whom she named Naga and who served as her animal companion.
Over the next thirteen years, Korra demonstrated a prodigious talent which allowed her to quickly master the arts of waterbending, earthbending, and firebending, as she completed her training of the latter by 170 AG. Around this time, the Water Tribe Chief Unalaq constantly sought Tonraq's permission to train Korra in the spiritual ways of the Water Tribe, but his estranged brother shot down his offers.
After the incident, Tonraq and Tenzin, Korra's eventual airbending master, came to a decision to have Korra secluded in the Southern Water Tribe compound for her own safety. However, due to the efforts of Tonraq, Sokka, Zuko, and Tenzin, the attempt was thwarted and the criminals were apprehended. A year after Korra's identity as the Avatar was established, four members of the Red Lotus named Zaheer, Ghazan, Ming-Hua, and P'Li attempted to kidnap her to train her in the ways of the Red Lotus. After performing waterbending, earthbending, and firebending before them, her identity as the Avatar was established, and her training to become a fully realized Avatar began in earnest under the Order's watchful eye. At the age of four, she discovered her identity as the Avatar, a fact she proudly announced to the Order of the White Lotus when they visited her home at her family's request. Korra was born to two waterbenders named Tonraq and Senna in the Southern Water Tribe, immediately following the death of Avatar Aang.