The Tyrannosaur Buck is the secondary antagonist of The Lost World: Jurassic Park. As its name implies, it is a large, male, powerful Tyrannosaurus Rex and is the individual hunter Roland Tembo seeks to hunt during his travel to Isla Sorna.
It is first mentioned by Roland Tembo when he says he wants to hunt down the most powerful predator, a male Tyrannosaurus rex. After the Ingen hunter team successfully traps and subdues several dinosaurs, Roland and Ajay wander into a nearby rainforest and find the t-rex nest, but only encounter the baby T-Rex. In order to hunt down the
male,they kidnap the baby and use it as a lure to make the Rex pair appear.However,that same night,Ian and his team appear in the hunter camp and free the captured dinosaurs,which promptly begin destroying everything in their way.In the ensuing chaos, a Triceratops throws a jeep high into the sky, causing Roland and Ajay to jump off the tree they were hiding to wait for the Rexes to appear. Nick takes the young T-Rex and brings it to the mobile lab so they can heal it. Unfortunately for them, its cries and its scent bring the angry parents to the laboratory, where they want their son back. The now-healed infant returns to its parents,who seem to return peacefully to the forest...only to go back and destroy the mobile lab by throwing it off a nearby cliff.Eddie Carr tries to save them, but the loud noises of his vehicle attractthe attention of the pair, who tear apart the car and kill and eat Eddie.Finally satisfied with their work, the two T. Rex left and the trailer inhabitants were rescued by the InGen team. The Tyrannosauruses are not seen again until they find the survivor camp, attracted by the scent of the infant because Sarah's shirt was soaked with its blood. The male pokes his head in one of the tents,but is promptly startled by Carter,who screams in fear at the sight of the animal,alerting his fellow survivors. The female T-Rex chases a handful of people and corners them on a waterfall, while another handful flees to the tall grass, where they are attacked and killed by several Velociraptors. The male is then left behind, scavenging for any remains. Seizing this is the perfect opportunity to hunt what he's been looking for, Roland attempts to shoot the Rex,but discovers his weapon was sabotaged by Nick Van Owen,so he tranquilizes the Rex instead with several darts,hoping and overdose of them would kill him. Unfortunately for Roland, Ludlow came across the still alive T. Rex and ordered him to be secured for transport to San Diego where he hoped to display him, along with his infant, in the new Park being built there to replace the one at the now destroyed Isla Nublar. Unfortunately, sometime during the trip, the T. Rex stopped breathing and entered a comatose state. In an effort to save the animal, he was administered an amphetamine to counter the large dosage of tranquilizer given to him when Roland shot him. The T. Rex, now in a berserker state, broke out of his containment unit and attacked those serving on board the ship. Somehow the T. Rex was lured into the cargo hold, where he stayed until Ludlow foolishly ordered the area checked once the ship docked at the InGen Docks at San Diego. The T. Rex, now free, broke through the dock check point and wandered into San Diego. Doctors Sarah Harding and Ian Malcolm then devised a plan to lure the raging animal back to the ship by using the infant to bring him. As they went to the facility to recover the baby, the male Rex found a house with a backyard pool,from which he began drinking water eagerly. A dog barks at the intruder creature, but is promptly silenced by a growl from the carnivore. The noises wake up a child who eagerly drags his parents to the bedroom to show them the dinosaur. They discover the Rex has just killed and eaten their dog.When the kid takes a picture of him, the Rex snarls loudly at them,scaring the parents. He later makes his way into downtown and rampages, causing a lot of havoc, by biting traffic lights, smashing a bus and scaring everyone. Doctors Malcolm and Harding, who had recovered the infant by this time, came upon the scene and then led the T. Rex back to the docks. Returning the animal to the ship, Doctors Malcolm and Harding found that Ludlow, who had given the police orders to kill the Buck and leave the infant alive, had followed them in an effort to recover the infant T. Rex. Hearing the infant's call from the cargo hold of the ship, Ludlow entered only to, unbeknownst to Ludlow, be followed in by the adult male. Attempting to capture the growling infant bare handed, Ludlow realized only too late that he had been trapped.Attempting to scurry up the stairs back up to the main deck, Ludlow was grabbed in the Buck's jaws, who brought Ludlow back to the cargo hold floor where he dropped him. Attempting to stand back up, the male T. Rex pushed Ludlow back to the floor where he proudly watched his son pounce the hapless executive. However, this victory was short lived as police helicopters surrounded the gaping cargo hold doors. Their guns aimed to fire, it was only in the nick of time that Dr. Ian Malcolm was able to get the doors closed and the Buck tranquilized by Dr. Sarah Harding. The Buck and his infant were then shipped back to Isla Sorna, where they were spotted with the Buck's mate, the three apex predators reunited as family.
- The face of the Buck is adorned with many facial scars and many of the teeth in his mouth are broken or missing. This is indicative towards the animal participating in fights for mating rights or dominance.
- It's curious that Roland wishes to hunt the Tyrannosaurus Buck when the female Tyrannosaurus is actually larger. This could possibly stem from that fact that Roland is a professional hunter and in sport hunting it is the male that is prized for it's size and adornment and Roland did not know that it is the female that is holds the size.
- The T. Rex animatronic in Jurassic Park /// was actually the same animatronic for the Buck in The Lost World: Jurassic Park. Stan Winston Studios repainted the animatronic lighter colors in order to represent a sub-adult individual, however they can both still be recognized as the same robot by the facial scaring on the right side of the muzzle.