The 'fuel' repeatedly mentioned is almost certainly marine diesel. Even when exposed to an open flame, marine diesel — or DERV — would not burn in the manner shown. Correction: this is a factual mistake, not an anachronism.
When Danny Rich strikes the snake with a mattock, a metal-on-metal sound is audible. This goof is a conspicuous error; it is not an audio-visual synchronisation problem.
The film asserts that anacondas possess heat-sensing pits, but they do not.
When Serone uses dynamite to destroy a blockade across the river, a falling branch knocks the spare fuel barrels overboard, leaving them with only one for the rest of their journey. Yet later the vessel is shown from the stern with all five barrels fastened back in their original positions.
When Danny climbs aboard the boat they find, his shoes and trousers remain dry, despite having waded through the water to reach it. His shoes also leave no marks on the deck.
When Paul tips blood over Danny and Terri, they are already marked by it before it even makes contact. Moreover, after the blood has "poured" onto them, it leaves no additional traces.
When Mateo is initially attacked by the anaconda, his hair is worn loose. In subsequent close-ups it is tied back.
In the "firefly" scene, Terri's lingerie strap alternately appears and disappears from one shot to the next.
At 1:09:30, having just clambered out of the river, Terri leans over to help Danny as the anaconda first attacks him, revealing that the back of her top is dry (lighter) while the front is wet (darker).
When Serone begins to strangle Dr Steven Cale after piercing him with a dart, you can already see blood trickling from his throat.
In the shot immediately before the anaconda seizes Mateo, his arms are raised; in the subsequent shot, they are lowered.
~59:38 After Serone is rendered unconscious, the subsequent scene shows the barge completely intact with all the fuel still on the deck.
As Serone is fishing for the anaconda and the struggle begins, he sends Gary to illuminate the snake. Gary takes the right-hand spotlight, yet someone else is operating the left-hand light, even though everyone else is on the aft platform at that moment (Dr Steven Cale is in his cabin, unconscious; Mateo is already dead).
In the firefly sequence, viewers can clearly make out that the "fireflies" are simply lights attached to strings, with the strings plainly visible.
At roughly 1 hour 21 minutes into the film, as Terri flees the snake through the smokestack, she is shown wearing a bodysuit around her waist that is not visible at any other point.
Wild boar are not found in the Amazon.
The fuel drums that fall overboard would not sink; they would remain afloat.
Throughout the film, the snake emits a shrill, screaming sound — a noise that real snakes do not produce.
Sarone's rifle is a bolt-action Winchester Model 70 Sporter, which must have its bolt cycled manually to chamber each successive round. In the film, the cast failed to operate the bolt and fired the weapon as though it were a semi-automatic.
By the time Serone hauls the boar aboard the boat, rigour mortis has already set in. In reality, it would take considerably longer for that to happen.
At the end of the film, in one last fright, eggs are shown beginning to hatch. Anacondas are viviparous — they retain their eggs inside their bodies, which have no shells, and the young are born alive once fully developed.
Anacondas have round pupils rather than the "evil-looking" slitted pupils they are often portrayed with.
The snake very rarely kills its victims in a manner appropriate to a constricting snake such as the anaconda - a constrictor must first "latch onto" its victim using its mouth. It would not simply spiral around its prey. The latching provides an "anchor" to facilitate the wrapping and subsequent constriction.
At the end of the film, when Terri fires at the anaconda, she is using a bolt-action rifle. While many bolt-action rifles can hold more than one cartridge, the bolt must be cycled by hand to eject the spent case and bring a fresh cartridge into the chamber. Terri never cycles the bolt, yet she is shown firing the weapon multiple times.
Anacondas don't feed on several human-sized prey in succession. After swallowing such a large meal (a process that can take several hours), the snake will find a safe, secure spot and remain motionless for months while it digests the meal.
Anacondas, like other snakes, need at least several minutes to swallow their prey. They cannot do so as swiftly as the snakes that swallowed Serone and Gary.
Anacondas do not attain the speeds of a cheetah in pursuit. They can strike with comparable swiftness, but they cannot chase prey that quickly, not even when swimming.
Anacondas don't disgorge their prey merely so they can hunt again. They will sometimes do so for safety reasons — for example, if a predator threatens them and they cannot afford to be sluggish with such a large meal in their stomach, or if the prey proves too big to swallow.
The anaconda that attempts to eat Westridge's finger is smaller than a newly hatched anaconda would be. The smallest hatchlings are roughly one foot long.
While the snake is coiling around Serone, he remains conscious even as his face swells from constricted blood vessels. In reality he would be highly unlikely to still be alive in that state and would almost certainly be unconscious.
The film’s opening title crawl states that anacondas can grow up to 40 feet in length. Most herpetologists regard this as unlikely; credible reports suggest anacondas may reach about 26 feet, and a skin recovered from the Brazilian jungle was reportedly 32.8 feet long, but snakes of 10–15-foot length are much more common. Researchers believe that claims of even larger specimens often stem from skins or other remains that were stretched or distorted during preservation.
Although some snakes have been reported to behave differently, anacondas do not swallow their quarry while it is still alive. Research has demonstrated that constrictor snakes (including anacondas) can recognise their prey's heartbeat, and they continue to constrict until that heartbeat stops, after which they swallow the animal.
The heads of the anacondas in the film are more reminiscent of vipers and other venomous snakes than of genuine anacondas or other pythons.
The anacondas in the film are considerably larger than true anacondas and exhibit behaviours that real anacondas simply cannot perform. Real anacondas cannot grasp prey with their tails, cannot lunge from trees to snatch falling animals, and cannot rise that far out of the water as the one that seized Gary did. Furthermore, the snake that ought to have died from the explosion is depicted on fire yet still alive.
In the film, the water appears much clearer than it would in real life when Cale enters the water to free the rope and when the anaconda is shown with Gary inside it.
Many viewers claim the film constantly references the anacondas' babies, but that isn't accurate. When juvenile snakes appear on screen they aren't all boa constrictors — there are perhaps only a couple of actual boas; the majority of the smaller snakes are baby anacondas. Likewise, the film does not continually return to the young: only a couple of scenes involve them — when the babies fall onto the boat and when Terri discovers a nest of youngsters.
After a snake submerges with the axe embedded in its head, Danny appears to drop the same axe onto the jetty. (Correction) Danny only moves slightly as if to drop the axe, and you don't see or hear the axe fall.
Near the film's end, when Jennifer Lopez's character fires several shots into the snake's head she is shown handling a bolt-action rifle, yet she never cocks the weapon and does not pull the trigger on the final shot. On closer inspection it becomes apparent the moment is replayed — the take was acted and edited differently. That was a commonplace filmmaking technique in the 1990s.
Denise is still breathing despite apparently having been fatally strangled by Paul. In reality, she might merely have lost consciousness and then drowned after being shoved overboard.
Anacondas are native to South America, not in Borneo, which is on the opposite side of the world. This factual error occurs in ''Anacondas: The Hunt For The Blood Orchid'', not in ''Anaconda''. ''Anaconda'' is set in the Amazon.
It is impossible that Serone survived after being stabbed in the back with a dart and falling into the water, since he sank whilst in a dazed state; he should have drowned.
At around the 35-minute mark of the film they show the boat heading straight on, even though an island would have blocked its path because the vessel was too large to go around on either side.
Cale said the only thing he feared in the water was the candiru akus. If anacondas were as dangerous as depicted in the film, he ought to have known that and would have been reluctant to enter the water for that reason. He should also have been wary of creatures such as caimans.
There is no explanation for why the fireflies stop flashing shortly before the anaconda emerges from the water to seize the jaguar.
As the boat pulls away from the tree, a cut to the waterfall depicts the water streaming upwards.
Around the film's midpoint, during the scene where the monkeys appear to be "warning" the documentary-makers, close-up shots show that several of the monkeys are fastened to the branches on which they are perched by a thin cord.
At one stage the snake coils around Gary, sending him into a spin. Just as it is about to wind itself around his arms and shoulders, he flings his arm out and upwards and it passes through the snake.
After the first anaconda smashes through a pane of glass to reach Terri, Serone fires a tranquiliser dart into its mouth. As the snake reacts to the dart, the wires beneath it that control its movements are clearly visible.
When Terri shoots at the anaconda, the victim clamped in its jaws is clearly a mannequin.
At the start of the film, when Jon Voight begins cutting the fish, he makes a single cut, yet in the next shot the fish appears intact once more.
