Wearing his lionskin cape and swinging his trusty club, Hercules, the strongest man on Earth, tramped down a dirt path that led into a swamp. The smell of rotting vegetation filled the air. His latest assignment was to kill the hydra, a horrible water snake that lived somewhere in the marshes. "How do I get myself into these things?" the hero asked himself.
This fearsome animal had nine heads, and one of them was immortal. Its breath was so poisonous that just being touched by it was lethal. Fortunately, Hercules’ young nephew Iolaus (ey-oh-LAY-us) was along on the trip. He couldn’t be much help – he was just a kid! – but at least he was company.
The two trudged deeper into the stinking swamp. Bubbles of gas rose and broke at the surface of stagnant pools. Mists rose and hid the Sun. The path widened a bit. Off to one side, a big hole in the ground led back under a rock. It was the home of the hydra. The leaves and grasses around the opening were dead – killed by the creature’s dreadful breath.
Hercules prepared some flaming arrows and shot them into the hydra’s lair. The enraged animal slithered out, hissing, squirming, and coughing from the smoke. Hercules picked up his club.
He attacked the beast and knocked one of the animal’s heads off. But look! Two new horrible heads grew in its place and hissed at him. Hercules knocked off another head. Two more grew. This was getting him nowhere.
As Hercules vainly hacked at the hydra’s necks, he felt a sharp sting in his foot. Now what? Hercules looked down and saw a crab pinching him. It had been sent by the goddess Hera (HEER-a), who had always disliked Hercules. He kept fighting.
Meanwhile, hoping to frighten the serpent, Iolaus set some nearby trees on fire. Then he had an idea. He broke off a burning branch. The next time Hercules knocked off a head, Iolaus dashed in and burned the spot where the head had been, so new heads could not grow. Together, Hercules and Iolaus destroyed the hydra’s remaining mortal heads.
Then Hercules reached for his sword. He cut off the hydra’s immortal head and buried it under a rock. Although it was still alive and as evil as ever, it could do no more harm. The hero and his nephew congratulated each other.
But what about the crab? In the heat of the fight, Hercules stepped on it, squashing it. To show her gratitude to the small creature, Hera placed it in the sky as a constellation.
The crab, or Cancer, as we call it, is not a bright constellation. On a March evening, if you face south and look overhead, you can see the twin bright stars of the constellation Gemini. Look carefully to the left of the twins to find the dim lopsided square of stars that forms the body of the crab – as inconspicuous in the sky as a crab is in the sea.