Jaguars, unlike leopards, are not generally known to kill humans, although there are a few cases of this happening.
For the waterfall jump scene, Rudy Youngblood performed his own stunt, jumping in a harness from a 15-story building in Veracruz over about 10 takes. (The shot was later digitally composited with the real waterfall.) After director Mel Gibson harassed Youngblood about the actor's initial hesitancy and fear of jumping, Youngblood got together with the stunt crew and goaded Gibson into taking a jump for himself.
Because of heavy rains in Mexico, the released date had been changed from 4 August 2006 to 8 December 2006.
The amount of digital footage shot would approximately equal 2 million feet of conventional film.
Many substantial speaking roles in the film were filled by Mayan people who had never acted before. For instance, the sick little girl who curses the hunting party as they and the captives pass right before entering the city, was played by a seven year old who lived in a dirt-floored hut in a village not unlike Jaguar Paw's.
There was severe flooding in the southern region of the country during filming, which displaced at least a million people. The crew helped with some flood relief.
The teaser trailer for the movie has an almost entirely different cast than the one that ends up in the film.
Due to the unpredictable climate in the rain forest of Mexico, special care was needed to protect the digital cameras. Under extreme heat, they were covered with space blankets to reflect the heat. Temperature was closely monitored via thermometers added to the cameras. While shooting at a waterfall, the cameras were protected in specially built Hydroflex splash bags designed by Pete Romano.
During the course of filming the 170-ft waterfall for the scene in which Jaguar Paw (Rudy Youngblood) jumps to escape the headhunters, a real cow that was attempting to cross upstream went over the waterfall. Remarkably, it emerged from the fall alive and the dazed and confused animal banged with the current along rocks near the bank. Mel Gibson and crew were certain the cow was done for, but after a local man swam into the river and calmed it, the cow climbed up on bank and began eating grass as if nothing had happened.
In casting, it was important to Mel Gibson that he and Farhad Safinia find actors that matched the archetype each character represented. For instance, Rudy Youngblood struck Gibson as fitting the mythic archetype of a hero. Gibson saw that as necessary to allow people to identify with the film, since the movie's context is unfamiliar to most viewers, being in a foreign language and concerning an indigenous culture in the 16th century.
As a teenager, Mel Gibson was actually once called 'almost' by an older boy, which was a deep insult to him. This inspired the line in the movie in which Jaguar Paw is called 'almost' by one of the headhunters.