These cages were used in Jurassic Park to transport small and mid-sized dinosaurs. Specifically, a Velociraptor was transported in one to the raptor pen prior to the Isla Nublar Incident. A forklift is used to move the cage to a trackway, at which point wheels on the bottom allow it to be moved smoothly when pushed by several men. There are ladders on both side of the cage, near its front, to allow workers to climb to the top. From here, the cage can be opened by pulling a slat-like gate up, much like a factory shutter. This was meant to minimize danger posed to the worker while opening it.
Unfortunately, the Velociraptor‘s strength had not been taken into account, and it managed to charge with enough force to push the cage backwards and allow it to escape. The worker, Jophrey, was then seriously injured–or perhaps even killed–by the Velociraptor as gunshots can be heard; this leaves the fate of both Jophrey and the Velociraptor in question.