Could anyone tell me whether there is any reliable evidence of a giant species of homo sapiens (or even Neanderthal) ever living on earth.
Of course, that begs the question of what you mean by "giant". Some tribes may be taller than average (the Masai come to mind), though I'm certain that that is not what you mean.
In the sense that you obviously mean (ie, 10 feet tall and much much more), the answer is an obvious "no".
I heard of a History Channel documentary that made this claim, but am unsure of the science.
It's very sad how these specialty TV channels have all become the same in their whoring after ratings. Arts and Entertainment (A&E) used to specialize in showing concerts, operas, plays, ballets, etc, but now you never see that anymore as they have become indistinguishable from any other channel. The science and learning channels used to have nature and historic and educational shows, but now they appeal to pseudo-science with "reality" shows about ghosts, UFOs, and Bigfoot. The History Channel used to specialize in history and still do to a point, but its programming is also heavily laden with pseudo-scientific nonsense, such as "evidence of a giant species of homo sapiens".
But so that we can see what you had seen in order to evaluate it, could you please identify that documentary as best as you can?
... special individuals who enjoyed special warrior status (Goliath being a later example) or a race of people of general giant stature (perhaps seven to twelve feet tall on average?)
There are individuals who grow freakishly tall (7 to 9 feet) usually due to giantism. That condition is accompanied by health problems. The tallest man on record, Robert Wadlow, at 8'11.1" required leg braces to walk. He died at age 22 from an infection because of his autoimmune disorder. John Rogan, 8'9", suffered from ankylosis. When he was young he needed to use crutches, but later he could no longer walk nor even stand. He died at age 40 from his condition. John F. Carroll, 8 feet tall (8 feet 7¾ inches if his spine were straight), suffered from severe spinal curvature deformity and died at age 37. André the Giant (see The Princess Bride) was 7'4" and was much more functional, but he also died early, at age 46 of congestive heart failure.
I think you see the pattern. An individual like André the Giant, an anomaly in a normal human population (since when were the French a race of giants?), could indeed stand out, though one factor in his favor was that he was smaller than most other giants. Larger giants would not be able to withstand the rigor of battle or even be able to walk to the battle. An entire tribe of such individuals would be unable to survive.
I thought one of the other respondents had mentioned a rule about how an individual's musculoskeletal structure would have to change in order to allow him to become gigantic and remain functional. I don't care how many times you've watched Ant-Man become Giant-Man in Captain America: Civil War. And the ant that grew to dog-size in Ant-Man would have quickly died from asphyxiation (ants have no lungs, but depend on oxygen diffusing into their bodies via a network of tubes, something that only works when you're small). From our real-world human giant examples, a little past 8 feet is the limit. Going past that requires extensive changes to the body.
quote:Bodies change in size by what is called the square-cube law. ... So, if you double the size of an organism, you increase the surface area only four times and you increase the volume it holds 8 times.
. . . if we double the size of the animal, the mass of the animal is going to be eight times greater, it will weigh more in other words, . . .
How does the square-cube law pertain to size? Well, where it comes into play is that with an increase in size of an animal, there has to be a relatively greater in crease in size of its supporting structures. If we look at the leg bones of a mouse, a human, and an elephant and scale them so the lengths are the same, they might look something like this. Note that the elephant leg bone is considerably thicker than the humans and the humans is thicker than the mouse. What this means is that a Liliputian could not exist. A human shrunk down to the size of a mouse would have limbs that the human could not move. They would be too heavy. Giants like Paul Bunyan that stand 20 ft. high would also be impossible because their form would have to be so drastically changed in order to accommodate the increase in size that the person would no longer look human.
Assuming those changes occur, there's also the problem of what such a giant would be capable of. For example, becoming the size of an elephant raises the problem that elephants can't jump. And if an elephant falls, it's almost certain to kill him. A human the size of an elephant would also face such limitations (again, forget Giant-Man! Even though you did see that with your own eyes.).
My question, by the way, relates to Genesis 6, which speaks of a race called the 'Nephilim' (translated 'giants' in the King James).
Which reveals the reason for any interest in this subject and the motivation behind promoting claims of ancient races of giants: purely religious. And it also illustrates the cause of so much creationist dishonesty: they'll use anything they can and distort and lie about anything they can in order to support their creationist theology, regardless of how false that theology is.
Other participants here have already pointed out much of this. In Message 7 Sci Cat shows someone holding an elephant femur when looks very similar to a human femur (except it's much thicker as expected from that comparative anatomy page quoted above). The origin of many fantastic giant beasts and human giants in ancient mythology was undoubtedly finding such bones. In Message 6 Coyote points out that all search hits on "race of giants" are on religious sites. In Message 4 Phat, a Christian, points out that there is a lot of fake "information" on the Internet and that you must be wary of it. In Message 9 Taq mentions the Cardiff Giant (do also follow the link that he provides), one of many known deliberate hoaxes to exploit the credulity of Christians. In Message 8 PaulK also mentions fake reports as well as faked photographs. There are contests judging one's ability to fake photographs, photoshopping them -- eg (from a Scientific American article on the subject), George H.W. Bush and Margaret Thatcher walking hand-in-hand through a garden when in reality they were at least six feet apart, Marilyn Monroe holding the crook of Abraham Lincoln's arm (she did seem to have a thing for US Presidents).
A number of such fakes involve the uncovering of giant skeletons (like 50 feet tall). snopes.com has one example at http://www.snopes.com/photos/odd/giantskulls.asp (the actual source of the reference to the cube-square law (see above). In another topic thread here (someone, please points us to it), a creationist posted some such faked photos as proof of giant skeletons having been found and in the process of being excavated. All fakes, every single one of them.
But that doesn't stop the creationists from promoting those fakes and lying about them. Never has stopped them and never will stop them. Ed Babinski is a former extremely fundamentalist Christian who committed the "unforgivable sin" of starting to think and to learn. He edited and published a collection of several deconversion stories, Leaving The Fold: Testimonies Of Former Fundamentalists. He is active on FaceBook, so look him up.
Two professional creationists, Carl Baugh and Kent Hovind, used a "photograph" from 1856 (according to Hovind) of a 11' 6" human skeleton found in an Italian mine. Both creationists had gotten it from another professional creationist, Clifford Burdick. Babinski researched it and found the claim to have no basis. In addition, at one of his presentations Hovind was told the second-or-third-hand story of another such find in a local mine which has since flooded so it's lost; Hovind immediately started including the story in his presentations.
BTW, Babinski includes that "photograph" in his article. It looks nothing like a photograph, but rather like a drawing. An artist looking at it immediately saw that the shadows did not correspond with the light sources, something that a photograph would not get wrong but someone making a drawing would.
So in summary, there is no evidence of any race of giant humans having existed. All "evidence" of such has been found to be deliberate fakes. Giantism in humans is unviable. In order for giantism in humans to be viable, it would require extensive changes to the human body, in which case they would become an entirely different species.
So then, the answer to your question is "no". But that shouldn't keep this from being an opportunity for you to learn.