In the original novelsEdit
Lord Greystoke and his very pregnant wife were marooned on the Atlantic coast of Africa by mutineers. Tarzan (young Greystoke) was born soon after, and his mother detached from the reality of their situation. His father built a cabin, which he heavily reinforced to keep out attacking animals. When Tarzan was a year old, his mother died, and his despairing father accidentally left the cabin latch open. Kerchak, the sometimes-violent leader of the anthropoid ape tribe, entered and killed Lord Greystoke. This species unknown to science had a primitive language, calling itself the Mangani.
An infant ape had died that morning, and its' mourning mother, Kala, was still carrying its' body. When she saw Tarzan crying, she dropped her dead infant in his crib and took him up. She raised him as her own. Tarzan became a feral child, speaking only the language of the Mangani, but no English, and unaware of human civilization.
In the Disney franchiseEdit
Like in the literature, they are again marooned on the Atlantic coast of Africa after their boat caught fire and sunk (though it isn't explained how the fire started). They then build a massive tree-house from salvage. They are then found and killed by Sabor the leopard, though Tarzan was missed. Kala later found their bodies along with cat-made paw-prints of (supposedly) their blood: evidence that Sabor had been responsible. Luckily she had found Tarzan and both managed to escape Sabor who was still at the tree-house. Tarzan eventually forgot about them later on in the film until recently. He would also at some point learn that his parent's deaths were all Sabor's doing (though Sabor had also been killed by Tarzan himself earlier in the film).
They are also mentioned in the sequel television-series The Legend of Tarzan.