Dinosaurs were reptiles that first appeared on Earth around 231,000,000 B.C.
After the extinction of the dinosaurs and the evolution of humans, dinosaurs were often featured as decorations. These dinosaur decorations were placed in places like parks and miniature golf courses.
In 1955, Biff Tannen stowed away in the DeLorean time machine. When it returned to 1991, he stole it from the Institute of Future Technology. While Doc was locked in the lab, he recruited volunteers to travel through time in an 8-passenger DeLorean to chase Biff through time and bring both DeLorean time machines back to 1991. While being chased through time, Biff traveled into an active volcano during a time period populated by dinosaurs. Biff's DeLorean later stalled, and the 8-passenger DeLorean was able to bump both time machines back to 1991, and afterward Biff was returned to 1955.
Dinosaurs were also seen several times by the Browns on their trips to the past in 1991 and 1992, including a Tyrannosaurus rex while visiting the Cretaceous Period. In one alternate timeline, dinosaurs resembled their human counterparts due to continued evolution after Dr. Emmett Brown prevented an asteroid impact. Doc and Marty subsequently encountered a Tannensaurus during this time. The following year, Verne brought the egg of an unidentified species of dinosaur back from the past. Hatched in 1992, the baby dinosaur, whom they nicknamed "Tiny", wreaked havoc before it was returned to the prehistoric era from whence it came.
On October 21, 2015, Biff Tannen stole the DeLorean time machine. Unable to figure out how to make it travel through time, he hit the display of the time circuits with his cane. He was sent into the past, during a time when the land that would be Hill Valley was under the ocean, and dinosaurs roamed the Earth. He encountered a Velociraptor, which stole the Blast from the Past bag containing the Grays Sports Almanac. Biff hit the raptor in the head with his cane, retrieved the bag, and traveled forward in time to November 12, 1955.
- Back to the Future: The Ride
- Back to the Future: The Animated Series
- Back to the Future (Harvey Comics)
- Back to the Future: The Game
- Episode 4: "Double Visions" (dinosaur model at the Hill Valley of the Past exhibit)
- Back to the Future (IDW Publishing)