Tarzan

In the second half of the 1800s, an English couple and their infant son escape a shipwreck, ending up near uncharted rainforests off the coast of Africa. The couple craft themselves a treehouse from their ship's wreckage, but are subsequently killed by Sabor, a rogue leopardess. Kala, a female mountain gorilla who recently lost her own child to Sabor, hears the cries of the orphaned human infant and finds him in the ruined treehouse. Though she is attacked by Sabor, Kala and the baby manage to escape. Kala takes the baby back to the gorilla troop to raise as her own, an act which the leader and her mate, Kerchak, disapproves of but grudgingly lets her proceed with. Kala raises the human child, naming him Tarzan. Though he befriends other gorillas and animals, including a young female gorilla named Terk and the paranoid male elephant Tantor, Tarzan finds himself treated differently because of his different physique, so he makes great efforts to improve himself. As a young man, Tarzan manages to kill Sabor with a crude spear he made, gaining Kerchak's reluctant respect.
The gorilla troop's peaceful life is interrupted by the arrival of a team of human explorers from England, consisting of Professor Porter, his daughter Jane, and their hunter-guide Clayton. The explorers are looking to study gorillas. Jane accidentally becomes separated from the group and chased by a pack of baboons, and Tarzan saves her. He recognizes that she is the same as he is: a human. Jane leads Tarzan back to the explorers' camp, where Porter and Clayton both take great interest in him â the former in terms of scientific progress while the latter hopes to have Tarzan lead him to the gorillas so that he can capture them and return with them to England. Despite Kerchak's warnings to be wary of the humans, Tarzan continues to return to the camp, where Porter, Clayton, and Jane teach him to speak English as well as what the human world is like. He and Jane begin to fall in love. However, the English explorers have a difficult time convincing Tarzan to lead them to the gorillas, due to Tarzan's fear of Kerchak.
The explorers' ship returns to retrieve them. Jane asks Tarzan to return with them to England, but Tarzan in turn asks Jane to stay with him when Jane says it is unlikely they will ever return. Clayton convinces Tarzan that Jane will stay with him forever if he leads them to the gorillas. Tarzan agrees and leads the party to the nesting grounds, while Terk and Tantor lure Kerchak away to avoid having him attack the humans. Porter and Jane are excited to mingle with the gorillas, but Kerchak returns and when he sees the humans, attacks them. Tarzan is forced to hold Kerchak at bay while the humans escape. Kerchak accuses Tarzan of betraying the troop. Kala takes Tarzan to the treehouse she found him in, shows him his true past, and tells him that she wants him to be happy whatever he decides. Tarzan puts on a suit that belonged to his father, signifying his decision to go to England.
When Tarzan boards the ship with Jane and Porter the next day, they are ambushed by Clayton and his band of stowaway thugs. Clayton hopes to seize the gorillas now that he knows where the nesting grounds are, and locks Tarzan, Jane and Porter away to stop them from interfering. Tarzan manages to escape with the help of Terk and Tantor, and he returns to the gorillas' nesting grounds. Clayton mortally wounds Kerchak and then engages Tarzan in a fierce battle across the vine-covered trees. Tarzan traps Clayton using vines. Clayton angrily cuts his way free, but inadvertently hangs himself with a vine tangled around his neck. Kerchak, with his dying breath, finally forgives Tarzan names him new leader of the gorilla troop. The rest of the gorillas are freed after scaring away the rest of Clayton's men.
The next day, Porter and Jane prepare to leave on the ship while Tarzan stays behind with the gorilla troop. As the ship leaves shore, Porter encourages his daughter to stay with the man she loves, and Jane jumps overboard to return to shore; Porter shortly follows her. The Porters reunite with Tarzan and his family and embark on their new life together.

Question: Who does Tarzan have to hold at bay?
Answer: Kerchak