Steg and Leda were the parents of Spike. They had lost all of their other eggs to Egg Stealers. A few moments before Spike hatched, Fast Biters got near the nest. Leda and Steg led them away from the nest and fought them. During the fight, the group collided with rocks, which fell on all of them, killing the Fast Biters as well as Steg and Leda.
An Egg Stealer, Orni, was about to get Spike's Egg but Ducky arrived at that moment and found Spike.
As it turned out in The Land Before Time XX: Flowing Fire Danger, Steg had a living sister, Stella, who found Spike while traveling to the Great Valley one day. Stella almost left the Great Valley with Spike, wishing to travel with Tippy's herd, but was eventually persuaded by Ducky to live in the Great Valley.