In his 1919 novel Tarzan the Untamed, Edgar Rice Burroughs places his hero in an awkward predicament – smack dab in the middle of a trackless desert, dying of hunger and thirst – and then hits on a rather grisly means of helping him out:
A shadow swung slowly across the ground beside him, and looking up, the ape-man saw Ska, the vulture, wheeling a wide circle above him. The grim and persistent harbinger of evil aroused the man to renewed determination. He arose and approached the edge of the canyon, and then, wheeling, with his face turned upward toward the circling bird of prey, he bellowed forth the challenge of the bull ape.
“I am Tarzan,” he shouted, “Lord of the Jungle. Tarzan of the Apes is not for Ska, eater of carrion. Go back to the lair of Dango and feed off the leavings of the hyenas, for Tarzan will leave no bones for Ska to pick in this empty wilderness of death.”
But before he reached the bottom of the canyon he again was forced to the realization that his great strength was waning, and when he dropped exhausted at the foot of the cliff and saw before him the opposite wall that must be scaled, he bared his fighting fangs and growled. … Once he stumbled and fell, and when he tried to rise he found that he could not – that his strength was so far gone that he could only crawl forward on his hands and knees for a few yards and then sink down again to rest.
It was during one of these frequent periods of utter exhaustion that he heard the flap of dismal wings close above him. With his remaining strength he turned himself over on his back to see Ska wheel quickly upward. With the sight Tarzan’s mind cleared for a while.
“Is the end so near as that?” he thought. “Does Ska know that I am so near gone that he dares come down and perch upon my carcass?” And even then a grim smile touched those swollen lips as into the savage mind came a sudden thought – the cunning of the wild beast at bay. Closing his eyes he threw a forearm across them to protect them from Ska’s powerful beak and then he lay very still and waited. … He feared that he might sleep and something told him that if he did he would never awaken, and so he concentrated all his remaining powers upon the one thought of remaining awake. Not a muscle moved – to Ska, circling above, it became evident that the end had come – that at last he should be rewarded for his long vigil.
Circling slowly he dropped closer and closer to the dying man. Why did not Tarzan move? Had he indeed been overcome by the sleep of exhaustion, or was Ska right – had death at last claimed that mighty body? Was that great, savage heart stilled forever? … Ska, filled with suspicions, circled warily. Twice he almost alighted upon the great, naked breast only to wheel suddenly away; but the third time his talons touched the brown skin. It was as though the contact closed an electric circuit that instantaneously vitalized the quiet clod that had lain motionless so long. A brown hand swept downward from the brown forehead and before Ska could raise a wing in flight he was in the clutches of his intended victim.
Ska fought, but he was no match for even a dying Tarzan, and a moment later the ape-man’s teeth closed upon the carrion-eater. The flesh was coarse and tough and gave off an unpleasant odor and a worse taste; but it was food and the blood was drink ….
I suspect Robert E. Howard must have read this passage and decided to top it. Because in his 1934 novella A Witch Shall Be Born, Howard place his own hero Conan in a similar situation – with the added twist that Conan has to pull off the same trick while being crucified:
The man hanging on the cross was the one touch of sentient life in a landscape that seemed desolate and deserted in the late evening. … Conan stared at that expanse of empty waste shimmering tawnily in the late sunlight as a trapped hawk stares at the open sky. … Curses ebbed fitfully from the man’s lips. All his universe contracted, focused, became incorporated in the four iron spikes that held him from life and freedom. … He hung motionless, his head resting on his breast, shutting his eyes against the aching glare of the sun.
A beat of wings caused him to look, just as a feathered shadow shot down out of the sky. A keen beak, stabbing at his eyes, cut his cheek, and he jerked his head aside, shutting his eyes involuntarily. He shouted, a croaking, desperate shout of menace, and the vultures swerved away and retreated, frightened by the sound. They resumed their wary circling above his head. Blood trickled over Conan’s mouth, and he licked his lips involuntarily, spat at the salty taste.
Thirst assailed him savagely. … He glared at the distant river as a man in hell glares through the opened grille. … He bit his lip to keep from bellowing in intolerable anguish as a tortured animal bellows. … The sun sank, a lurid ball in a fiery sea of blood. Against a crimson rampart that banded the horizon the towers of the city floated unreal as a dream. The very sky was tinged with blood to his misted glare. He licked his blackened lips and stared with bloodshot eyes at the distant river. It too seemed crimson with blood, and the shadows crawling up from the east seemed black as ebony.
In his dulled ears sounded the louder beat of wings. Lifting his head he watched with the burning glare of a wolf the shadows wheeling above him. He knew that his shouts would frighten them away no longer. One dipped – dipped – lower and lower. Conan drew his head back as far as he could, waiting with terrible patience. The vulture swept in with a swift roar of wings. Its beak flashed down, ripping the skin on Conan’s chin as he jerked his head aside; then before the bird could flash away, Conan’s head lunged forward on his mighty neck muscles, and his teeth, snapping like those of a wolf, locked on the bare, wattled neck.
Instantly the vulture exploded into squawking, flapping hysteria. Its thrashing wings blinded the man, and its talons ripped his chest. But grimly he hung on, the muscles starting out in lumps on his jaws. And the scavenger’s neckbones crunched between those powerful teeth. With a spasmodic flutter the bird hung limp. Conan let go, spat blood from his mouth. The other vultures, terrified by the fate of their companion, were in full flight to a distant tree, where they perched like black demons in conclave.
Ferocious triumph surged through Conan’s numbed brain. Life beat strongly and savagely through his veins. He could still deal death; he still lived.
Oh, and Conan does finally get off that cross thing. In case you were worried.