Most of film was shot under the original title "Hunter", it was only later when the creature design was changed that the movie became "Predator". The clapperboards showing the original title can be seen in the outtakes on the special edition DVD.
The original "Hunter" model was a large creature with a long neck, a head shaped like a dog and one big eye in the middle. This can be seen on the camouflage demo's on the DVD. It was only when Stan Winston moved in that the complete design of the now "Predator" changed, along with the title.
Two waterfalls are used in the climax of the movie, both near Palenque in Mexico. The first is Misol Ha, just outside the village (beginning and end of the sequence), and the other is Agua Azul about an hour's drive away (the middle part of the sequence).
Two of the actors portraying commandos besieged by the Predator have been elected to state governorships: Jesse Ventura (Independent) was elected Governor of Minnesota in 1998, and Arnold Schwarzenegger (Republican) was elected Governor of California in a hotly-contested recall election in 2003. In addition, Sonny Landham (Republican) ran an unsuccessful campaign for Governor of Kentucky in 2003. Both Landham and Ventura also sought to enter the Senate in 2008 in their states as, respectively, a Libertarian and an Independent. Both dropped out.
The weapon that Blain (Jesse Ventura) is using is a minigun. This is a weapon most commonly mounted on the side of a helicopter (or an aircraft carrier) and many, many modifications had to be made to make it usable in the film. It was powered via an electrical cable hidden down the front of Blain's trousers. The firing rate was slowed down to approximately 1/3rd the normal rate of fire, both to reduce consumption of blanks, and to make the spinning of the barrels visible on film. It is rumored that Ventura had to wear a bulletproof vest because of the forceful ejection of spent cartridges, but this is false. Unmodified miniguns eject out of the bottom, with the cases essentially falling out due to the force of gravity. Close examination of the film (especially the scene in which Mac fires the minigun at the fleeing predator, along with the other commandos) show that the ejection of the minigun was not changed.
The studio would not allow John McTiernan to shoot this film in anamorphic widescreen due to the complexities of the optical effects. As a sly sort of retaliation, the director added an anamorphic version of the film's opening 20th Century Fox logo, which looks noticeably stretched on screen.
Sonny Landham was hired to work on this film, but on one condition: the insurance company insisted on a round-the-clock bodyguard for Landham, not to protect the actor, but to protect everyone else from the actor (who was prone to bar fights, etc.).
John McTiernan admitted that actor R.G. Armstrong was too old for his part, but kept Armstrong simply because he liked him. Added to this, the actor wore "too much" tanning makeup to hide his age somewhat.
Due to health and safety regulations, Arnold Schwarzenegger was not allowed to light his cigar inside the helicopter near the beginning of the film. As a result the glow was added optically in post-production.
Jesse Ventura was delighted to find out from the wardrobe department that his arms were 1" bigger than Arnold Schwarzenegger's. He suggested to Schwarzenegger that they measure arms, with the winner getting a bottle of champagne. Ventura lost because Schwarzenegger had told the wardrobe department to tell Ventura that his arms were bigger.
During the closing credits, Shane Black is seen prominently displaying a copy of Sgt. Rock #408 (Feb. 1986). In the DVD commentary, John McTiernan notes that at the time, Arnold Schwarzenegger had an adaptation of Sgt. Rock in production, and that's why the comics were on set, so he could read them. He described the scene where Dutch (Schwarzenegger) walks up to Billy (Sonny Landham), who senses the Predator's presence out in the bush, as a "Sgt. Rock moment".
Third film in which Arnold Schwarzenegger wears a Seiko model H558-5009 diver's watch. Since nicknamed "The Arnold", it is highly sought-after by collectors and regularly trades for values in excess of its original retail cost. Its distinctive black collar and stainless steel fittings suitably complements Schwarzenegger's exaggerated arm muscles in his early films.
The sound editors called the Predator's shoulder gun the 'Parrot Gun', because when it moved independent of the Predator while aiming, it reminded them of "Peter Sellers with a rubber parrot on his shoulder."
Hawkins was originally supposed to wear a distinctive red beret, most likely inspired by the U.S. Army's maroon airborne berets, worn by American paratroopers. Shane Black refused to wear it, as he thought it would look ridiculous in the jungle. He later regretted the decision, as he felt it would have made his character stand out.
Shane Black hated the glasses he was given to wear as Hawkins. He wanted to wear authentic military-issue ballistic glasses worn by actual troops in the field, but the director wanted him to look as geeky as possible.
Being the first Predator movie they only show the thermal vision and infrared vision from the Predators point of view (in Predator 2 they introduce many other vision modes for the predator), but with good attention to details you can get hints that the Predator has different vision modes even in this movie; The Predator can obviously see and avoid the trip wires they hide everywhere in the forest (which would actually not be visible if the Predator only used thermal visions). The predator can also see if the soldiers are carrying any kind of weapons or knives and if they are unarmed, indicating the Predator has a different vision mode which makes him able to detect solid metal.
Peter Cullen was reluctant on taking the job of voicing the Predator as he injured his throat playing the title character of King Kong, but eventually accepted after seeing a picture of the unmasked creature.
Joel Hynek a special effects supervisor, who directed the design of the alien's camouflage effect, is the son of J. Allen Hynek, PhD. J. Allen Hynek originated the "Close Encounter" hierarchy for categorizing interactions with aliens. Dr. Hynek was an Professor of Astronomy at Northwestern University.
During an assault on the guerrilla outpost some sentences being shouted in Russian language by defenders can be heard. For example when a guy is trying to start a helicopter "Otkuda oni prishli?" can be heard which is "Where did they come from?" in English. This may suggest that the guerrillas were supported by Soviet communists who sent some people to help them.
Part of the shoot was 48 hours before Arnold Schwarzenegger's wedding rehearsal dinner. Jesse Ventura teased him about his nuptials, often ruining takes; director John McTiernan was not amused. Schwarzenegger missed the final preparation and Maria Shriver was not happy about that, because his mind was more on the film instead of they're wedding.
Maria Shriver discussed decoration plans concerning her and Arnold Schwarzenegger's new home with him over the phone during filming. She later spent a couple of days on the set in Mexico. The stunt crew played a practical joke on the newly married couple by putting frogs in their shower.
Predator had several hardships for the actors like leeches, mud, snakes, stifling humidity, heat and rough terrain. All of the night scenes were filmed during freezing cold temperatures, which was especially hard on Arnold Schwarzenegger during the latter half of the film when the mud he had to wear (actually pottery clay) became cold and wet. He was warned it would take his body temperature down a few degrees and he shivered non-stop, even when they tried to heat him with lamps (it just made the clay dry out). He tried drinking jagertee, a schnapps mixture to warm him but that just got him drunk.
The Predator was first designed by a special effects company the studio picked to save money on. Stan Winston later created the Predator for 1.5 million dollars; this other studio charged half that amount. Because of that, their Predator looked like someone in a lizard suit with the head of a duck, according to Schwarzenegger. When Winston was brought in to redesign the Predator, the final fight scene had to be reshot. The new Predator was eight and a half feet tall, but the recast Kevin Peter Hall was 7'2". The costume was heavy and off balance and Hall couldn't see with the mask on; because of that during the fight scene with Dutch, he actually did hit Schwarzenegger once.
Elpidia Carrillo's character Anna tells Arnold Schwarzenegger the story of the demons that live in the forest and skin their victims on yearly basis. This is the first indication that the Predator creatures have visited earth prior to the events of this movie.