The nigh-indestructible metal known as adamantium is exclusive to the Marvel universe and is mostly associated with Wolverine of the X-Men. The feral mutant is known for having his entire skeleton and trademark claws coated with the incredibly powerful metal. Wolverine's rival Sabretooth usually has only natural claws, but that has not always been the case.
On several different occasions, Sabretooth has been given an adamantium skeleton and claws to match his arch-enemy, to varying degrees of success. This change was originally temporary, but the most recent adamantium bonding may still be in effect. Here's a look at how the bestial and dangerous mutant has both gained and lost his upgrade over the years.
Sabretooth's First Adamantium Bonding
Captured by Apocalypse alongside Wolverine, Sabretooth had adamantium grafted onto his skeleton and claws. This was done to make him even more powerful while under the mental control of Apocalypse. Unfortunately for Sabretooth, the upgrades didn't last. Wolverine beat him in combat, and Apocalypse subsequently stripped the adamantium from the villain's skeleton. He then grafted it back onto Wolverine's skeleton, as the hero had still been using bone claws following a nearly fatal encounter with Magneto years before.
Suffering due to the immense pain inflicted by having the adamantium ripped from his body, Sabretooth was ironically saved by the Cajun X-Man Gambit, who used Sabretooth's skills and intel to uncover the location of one of the team's other enemies, Mister Sinister.
Sabretooth's Second Adamantium Skeleton
Shortly after this experience, Sabretooth would gain adamantium claws once again by way of a new version of the Weapon X Program during Frank Tiere and Sean Chen's 2001 run on Wolverine. Working alongside the infamous organization, he secretly used their information to hunt down everyone Wolverine cared about. He would later turn on the organization, getting revenge on them after he was nearly killed with adamantium bullets. Sabretooth was believed to have retained the metal bones and claws he gained from Weapon X even after the Scarlet Witch's reality altering events in House of M, but the depiction of this has been inconsistent throughout the years.
The use of adamantium arguable doesn't fit Sabretooth in the same way that it does Wolverine, with one reason being his claws. Sabretooth's claws are more like that of an animal's, thus lacking the higher amount of precision that Wolverine's claws provide. This is exacerbated further by Sabretooth's fighting style. While Wolverine is a lethal and savage fighter, he still has elements of skill that were honed by years of martial arts training. Sabretooth, who's a much larger and bulkier man, fights in an even more ferocious manner that earned him his own team of supervillains. While it boosters his strength, the new upgrades went against how he had become used to operating. Thus, it seems that even with adamantium bonded to his skeleton and the added strength that it provided, Wolverine, not Sabretooth, remained the best there is at what he does.