First Appearance: Captain America Comics #1 (March 1941).
Golden Age Appearances: Captain America Comics #1-6.
Modern Appearances: None.
Years Active: 50,000 B.C.E.-?
Tuk was a caveboy, similar to DC's Anthro. To quote from the text,
Ak, the last of the shaggy ones, called him Tuk! But the boy didn't realise that Tuk meant 'Avenger' and that he was destined to roam the prehistoric wilds of 50,000 B.C. in search of Attilan, Island of the Gods, to reclaim a lost throne...!Tuk actually has a somewhat complicated history. Years ago the the "hairless ones" are abandoned on the shores of an unnamed land. The "hairless ones" are a tall, handsome, muscular blond man, his sad-faced black-haired wife, and their infant son. They are left on the shores of the land by other hairless ones, who "departed across the long waters in a log with white wings;" the final words by the blond to his departing comrades is "Leaving us to the beasts, eh? Well, we'll be back. Do you hear? Kadir will fall!"
The pair are attacked by "Gholla the woolly horned" (some kind of rhinocerous); the blond wrestles and kills Gholla, but the rhino runs the blond through, and he dies in the arms of his wife. The wife is then attacked by "the four footed killers from the Forest. Kag, the lion-wolf was first to arrive." Luckily for the woman Ak ("the last of the shaggy ones," presumably meaning he is the last of the Neanderthals) swings down from the trees to rescue her, and "for many suns to follow" he serves her, "a living goddess." But then one day he is too long gathering food and she is attacked by "Gru, the lion." Ak kills Gru, but the woman dies from her wounds.
Ak relates all this to Tuk and then tells him that he is the child, now possibly 10 years old, of the "hairless ones." He leaves his "beloved rock" and goes journeying; he fights off "Goreks! Brain eaters!" and gets his life saved by his new friend, Tanir "the Cro-Magnon." In later stories Tuk fights the "pre-historic" "hairy ones," the "evil witches of Endor," helps the Princess Eve regain her throne in the city of Atlantis, and defeats the evil "Bonzo" and his gang of brutes (he kills them). (Tuk had one more adventure, which I haven't read.)
Note: Roger Stern had plans to show Tuk in the pages of Marvel Universe and to tie Tuk in to the history of the Inhumans, most likely to show that Tuk was the son of a pair of Inhumans, but, sadly, such was not meant to be.