Tantor is the Mangani word for elephant, thus all elephants are referred to as such.
Tantor usually appeared to be timid and even a downright coward who was easily spooked. However, he cared deeply for his friends and at times, he displayed considerable bravery despite normally appearing to be quite cowardly. For example, he boarded Clayton's ship to rescue Tarzan (complete with trumpet "Charge!" flair) and fought against a rogue elephant in the television series. He also seems to be somewhat of a germophobe and attempts to be an intillectual, though he tends to fail at the latter.
Tarzan first encounters Tantor as he was a kid during a dare by Terk to take an elephant hair, during the dare a very young Tantor thinks Tarzan is a piranha and informs his mother about it and she doesn't believe him until Tarzan bites one of the elephants which causes a stampede, after the aftermath it appears that Tarzan has died but he turns out to be alright and reveals he has managed to retrieve an elephant hair when he tells Tantor about he tells him that if he told him he would've gladly gave him one of his hairs.
Tantor continues to be his friend well into adulthood later in the film he Terk and some of their gorilla friends sneak onto the human's campsite and trash the place, later when Tarzan invites Jane Porter, her father Archimedes, and Clayton to the gorilla site Tantor and Terk provide a distraction to the gorillas's leader Kerchak so he won't find out about it, eventually he does find out about it and is enraged.
Later when Tarzan joins the humans and is put in a cell Tantor comes to the rescue and takes Terk with him being brave for the first time and fights off the men on the ship and they help fight Clayton's men so they won't make off with the gorillas. In the end Tantor celebrates the marriage of Tarzan and Jane along with Tarzan's gorilla family.
When a young Tarzan runs away from the gorilla family to try and find his own place in the jungle, a young Tantor and Terk go out to find him and bring him back home. He initially refuses to go back, but when he rescues the two of them from Uto, Kago and Mama Gunda, they become friends again and with Kala's arrival onto the scene, they all return home.
In a compilation of three episodes of The Legend of Tarzan (Tarzan and the British Invasion, Tarzan and the Volcanic Diamond Mine and Tarzan and the Flying Ace), Terk and Tantor are assisting Tarzan and Jane in preparing their first wedding anniversary and preparing the treehouse for the party.
By the time of the series/Tarzan and Jane, Jane and Professor Porter had since learned how to communicate with the animals. Tantor himself played a major part in several episodes. In Tarzan and the Rogue Elephant, a group of elephants move into the jungle escaping the rogue elephant Mabaya, Tantor becomes a mentor to the young Jabari, who has a strong resemblance to a young Tantor.
Another episode, Tarzan and the All-Seeing Elephant, focuses on Tantor searching for a mysterious deity to elephants high in the mountains. Though he doesn't truly find the All-Seeing Elephant, the experience serves to strengthen his friendship with Terk.