The Revenant goofs

At the start, once Glass has finished relieving himself, he is clearly shown doing up his trousers. The film is set in 1823, whereas the earliest zip-like fastener was not patented until 1851.

Fitzgerald employs the term "Texas ranger" in one of his monologues. According to the Texas Ranger Hall of Fame website, the very first recorded use of the word "ranger" was in 1823 by Stephen Austin, who at the time called for "ten men...to act as rangers for the common defence..." The website adds that it was not until 24 November 1835 that Texas lawmakers established a specific force known as the Texas Rangers. Therefore, Fitzgerald could not have been referring to such an organisation.

When Glass is trailing Fitzgerald through a stand of pines, the trees are arranged in tidy, straight rows. It's clearly filmed in managed woodland rather than genuine wilderness. The notion of conservation and organised woodland management in the US did not begin to take hold until nearly 1900.

When Hikuc speaks to Glass about having lost his family as well, his voice does not align with his lip movements, and the line seems to have been dubbed.

Glass wakes at dawn as members of the Arikara attempt to ambush him. He shoots one of them, then slings his shoulder bag over his neck and runs for his horse. He races past a tree (scene cut here!), trips and falls; when he gets back to his feet he is not wearing the shoulder bag as he mounts the horse. In the next shot the bag is on him again while he rides.

At the time of Elk Bear's lynching his hair was long and full, whereas whilst he was with Hugh Glass it was sparse, stringy and cropped.

Around 00:57:06, Bridger's hair is dry. Around 00:57:23, he's lying down and his hair is wet and dusted with snow.

At 59'30": There is no snow surrounding Bridger's head; in the following shot, at 59'49": snow is visible on the ground, in Bridger's hair and on his coat.

While Glass and Fitzgerald are fighting, the river flows from right to left. When Glass is climbing back out — the direction he had come from — the river flows from left to right.

Throughout the film you can hear green frogs and pickerel frogs vocalising in the background. Both species occur in the eastern United States and south-eastern Canada, so they would not naturally be heard in the North American Rockies. Furthermore, frogs are largely inactive and do not call during winter.

It is winter and Hugh Glass spends a great deal of time in and out of bitterly cold water. At one point he undertakes an extended downstream passage with most of his body beneath the surface (at times he is entirely submerged). Although he may conceivably have survived a bear mauling, it is highly unlikely that Glass could have avoided fatal hypothermia after emerging from icy water into freezing or near‑freezing conditions.

In the film, Glass is set upon by a mother grizzly accompanied by her two cubs. Yet the story is placed at a time of year — early to mid-winter — when grizzly bears, particularly a mother with cubs, would normally be hibernating. This seasonal setting is signalled by the weather and by a drinking scene about halfway through the film, when Captain Henry says to Fitzgerald, "Happy New Year."

In reality, the historical Hugh Glass was mauled by a mother bear around May 1823 — a time of year when bears are much less likely to be in hibernation.

As the Native American begins to walk away from the bison carcass, you can see he has left his arrows embedded in the wolves. He wouldn't do that. It's so labour-intensive to fashion arrows, arrowheads and fletchings that he would retrieve them from the carcasses and reuse them.

Early in the film Hugh Glass fractures his ankle, yet it appears to mend as the story unfolds. At one stage his ankle is even shown twisted the wrong way; under normal circumstances such an injury would take months to heal.

On several occasions in the film, characters are shown with the frizzen — the part that produces the spark in a flintlock — in the open position. In that condition the firearm will not discharge. More importantly, an open frizzen exposes the pan that contains the priming powder, so the priming powder can be easily spilt onto the ground, rendering the weapons useless.

The dilapidated church shown in the dream sequence is recognisably Orthodox, based on the architectural remnants — chiefly the nave and the iconostasis. The wall in front of the nave is covered with icons on both sides. However, behind that wall in the centre sits a crucifixion painting executed in the style of the early Renaissance. Such a "modern" painting would not normally be included among the other icons, which in Byzantine practice typically depict the Prophets, the Apostles, or Christ Enthroned.

Even without a knife, Glass's moustache — and his alone — stays immaculately trimmed throughout his ordeal.

Hugh Glass fires his single-shot flintlock pistol twice in quick succession on two separate occasions without reloading or having any time to do so. Loading such pistols is fairly time-consuming — the shooter must point the barrel upwards, pour gunpowder down the bore, insert a lead ball wrapped in a cloth patch, ram it down with a ramrod, add priming powder to the pan, close the frizzen and cock the hammer. He does this when he steals a horse from the French, and again when the Indians attack him shortly afterwards. An experienced shooter might perform these steps fairly quickly and possibly take a shortcut or two, but in both scenes the film shows him firing, then immediately vaulting onto a horse and shooting someone else with the pistol only seconds later.

In the film, DiCaprio spends extended periods tranquilly swimming in freezing water.

The large snail used as the reference for carving the canteen is a non-native apple snail. These non-native apple snails have only recently been introduced to the southern United States and certainly would not have been found in the northern United States.

As in the film "The Edge", the bearskin that Glass is wearing could not have been cured within the time available. It takes more than two weeks to cure a hide of that size.

In the novel upon which the film is based, Punke asserts "The barrel [of Glass's rifle] was short, only thirty-six inches... With a full charge of 200 grains of black powder, the Anstadt could throw a .53 calibre ball nearly 200 yards." However, no rifle from that period could achieve such performance, and Glass's actual rifle had a 44-inch barrel.

When Glass catches a fish and lifts it to his mouth to take a bite, it is apparent that the fish has been gutted.

Once it becomes apparent that Leonardo DiCaprio is actually floating down the rapids rather than a stunt double, the background makes it clear those shots were filmed at a different time of year: there is no snow and the distant woodlands are a vivid green. The only scene showing him in the river during winter is when he is climbing out.

The bows used by the Native Americans appear to be made from delicate lengths of cane. They don't seem capable of propelling arrows to the ranges and force depicted in the film.

Just before a fierce storm breaks, the Native American tucks Glass into a makeshift tent to recuperate. Not a single branch in that patch of woodland stirs.

An Inupiak voiceover accompanies a Pawnee. Inupiak is spoken exclusively in Arctic Alaska and belongs to a language family distinct from that of the Pawnee.

When the Native American who shares the buffalo fashions a makeshift teepee for Glass to sleep in overnight, the wind howls close to the ground while the trees remain almost motionless. It is evident that a wind machine was employed.

When Fitzgerald shoots the deceased Captain Henry from the horse, Henry topples off the animal's left-hand side. Yet when Fitzgerald approaches the body, whom he believes to be Glass, it is clear the corpse has fallen from the horse's right-hand side.

The fluctuating amount of moustache hair beneath Glass' nose (his philtrum is at times almost completely covered, yet appears hairless between takes).