When he was a cub, the Smilodon came in modern time through an Anomaly. He was found by a park ranger named Valerie Irwin which decided to raise and tame him, believing he was an escaped government genetic experiment. The Smilodon apparently regarded her as his mother. He killed Valerie 's boyfriend Dave in an unfortunate accident, forcing her to bury his body in the park's forest.
Once matured, the Smilodon began going into the park in search of more food. Valerie was apparently aware of this but did not attempt to stop him, even after he killed humans. His first victims is a paintballer named Warren. The following night, he attacks the park manager Peter Campbell in a train station and devours him.
The next day the Anomaly Research Centre team, which came to investigate, tries to trap him into a pit. However, things goes wrong and the Smilodon attacks and chases Nick Cutter, which climbs up a tree. The Smilodon then goes away.
Later, Nick Cutter goes to Valerie 's house and discovers that she harbors the Smilodon. However, Valerie traps him and threatens him with a tranquiliser gun, believing that he's part of a government organisation that had created the Smilodon in a genetic experiment and now wanted to recapture and experiment on him. Then, she sets the Smilodon on him, but he manages to escape the house and tries to defend himself with a pitchfork. Valerie puts herself between the two and tries to calm the Smilodon down, but he kills her in a frenzy. Just before he could kill Cutter, the team arrive and shoots him with a tranquiliser.
The Smilodon is then taken by Oliver Leek which use him as part of his creature army.
Long after these events, Oliver Leek captures Abby Maitland, Jenny Lewis, Connor Temple and Caroline Steel. He locks them in a sealed room and releases the Smilodon to kill them all. The Smilodon attacks Abby but she dodges his attack, causing the creature to accidentally trip the controls, which frees the group. The Smilodon then escaped into the facility.
Later, the Smilodon and the other creatures are lured back to the cage room by the feeding time siren and locked inside with Stephen Hart. All of them, including the Smilodon, set about surround Stephen and devour him.
The Smilodon then presumably dies when the creatures turn on and destroy each other.
- He is is slightly larger than the real animal.