While still a cub, Zabu’s mother and siblings were killed by the Man-Apes, a tribe of savage humanoids native to the region. Orphaned, Zabu was discovered by the wolf Zagah, who carried him home as food for his mate, Thana. Instead of allowing the cub to be eaten, Thana adopted him, raising him alongside her own offspring, Fheta and Jhet. Zabu grew quickly, earning Fheta’s admiration and Jhet’s jealousy. The rivalry culminated in a struggle for dominance after Jhet killed Fheta. Forced into combat, Zabu slew Jhet, an act that left him estranged from his adoptive wolf parents. He then wandered the Savage Land alone, learning to survive as he matured into adulthood.

Within a year of his birth, Zabu encountered the female who became his mate, and she later conceived his litter. Around this time, Maa-Gor, leader of a tribe of primitive cavemen, was systematically hunting sabre-tooth tigers, driving them toward near-extinction in the Savage Land. Maa-Gor and his warriors killed Zabu’s mate, enraging him. Tracking the tribe, Zabu found them attacking Kevin Plunder, the young son of British explorer Lord Robert Plunder. The tribesmen had already slain Kevin’s father and were about to kill the boy when Zabu attacked, scattering them. Maa-Gor attempted to spear Zabu from behind, but Kevin shot the chieftain in the shoulder with his father’s rifle, saving Zabu’s life.

Recognizing that Kevin had protected him, Zabu bonded with the boy. Together they withdrew to the Place of Mists, a region feared and avoided by Maa-Gor’s tribe. There, Kevin grew to manhood under Zabu’s protection. The tribe came to call him “Ka-Zar,” meaning “Son of the Tiger.” The strange mutagenic gases of the Place of Mists slowed Zabu’s aging, allowing him to remain in his prime as Ka-Zar reached adulthood.

Zabu remained Ka-Zar’s constant companion as the jungle lord began interacting with the outside world. He accompanied Ka-Zar on numerous journeys beyond the Savage Land, including travels to New York City and to the extradimensional realm of the Sheenarians. When the alien Terminus devastated the Savage Land, Zabu escaped alongside Ka-Zar and Shanna O’Hara Plunder. After the High Evolutionary restored the region, Zabu returned home with them.

He later accompanied Ka-Zar to New York when Parnival Plunder allied with Thanos, and again when Ka-Zar was wrongfully accused in a shooting incident. Although Ka-Zar and his family were at one point forced to leave the Savage Land temporarily, they soon returned and were reunited with Zabu.

At a later time, Zabu went missing, prompting Ka-Zar to seek help from private investigator Jessica Jones, who declined to become involved. Zabu eventually resurfaced but became entangled in a reality television spectacle involving Hercules, who subdued and hog-tied him as part of the program. Ka-Zar and Shanna tracked him down in New York, and Zabu was returned to them following a celebration of the show’s success.

When the cosmic Phoenix Force returned to Earth to select a new host, Shanna was summoned to the White Hot Room as a candidate, and Zabu accompanied her. The Phoenix empowered the assembled contenders, including Zabu, and forced them to engage in ritual combat. After defeating Devil Dinosaur and American Eagle, Shanna and Zabu faced Red Widow in a closely matched battle. The contest was ultimately interrupted when Echo was chosen as the Phoenix’s new host. She absorbed the fragments of the Phoenix Force from Shanna, Zabu, and the other participants, ending their empowerment.

One of the last surviving sabre-tooth tigers, Zabu remains the loyal companion of Ka-Zar and a formidable protector of the Savage Land.