Source Verification: Hydra
Every claim below is either what a named ancient source attests, in its own line or section, or a point where the sources themselves disagree.
What the Sources Attest
How many heads did the Hydra actually have?
Apollodorus, the source that narrates the labor in full, gives it nine heads, eight mortal and one immortal. Other ancient mythographers give very different counts, from far fewer up to as many as a hundred, so there was never a single agreed number in antiquity - the figure varies by author rather than settling on one canonical total.
Source: Apollodorus, Library 2.5.2
Why couldn't Heracles just cut off all the Hydra's heads?
Every time he smashed or severed one head with his club, two grew back in its place, so attacking it directly only multiplied the problem. He only succeeded once his nephew Iolaus began cauterizing each neck with a burning torch immediately after Heracles struck, which sealed the wound before it could regenerate.
Source: Apollodorus, Library 2.5.2
What happened to the Hydra's one immortal head?
Since it could not be killed like the others, Heracles cut it off anyway and buried it under an enormous rock, permanently sealing it away rather than destroying it. This solved the practical problem - the head could no longer threaten anyone from underground - without contradicting its immortality.
Source: Apollodorus, Library 2.5.2
Why did Eurystheus refuse to count the Hydra as one of the ten labors?
He ruled that Heracles had not defeated the monster unaided, since his nephew Iolaus had done the cauterizing that made victory possible. This disqualification, along with a second one for the Augean stables, is why the traditional count of Heracles's labors ended up at twelve instead of the ten originally set.
Source: Apollodorus, Library 2.5.2
What did Heracles do with the Hydra's blood afterward?
He dipped the tips of his arrows in it, since the blood carried the same lethal poison as the monster itself. Those poisoned arrows reappear later in his story, most significantly in the myth of his own death, where a robe treated with what was believed to be a love charm made from Hydra-poisoned blood ends up killing him.
Source: Apollodorus, Library 2.5.2
Where Accounts Differ
- head count variant
- Head count variant: Apollodorus gives nine heads; other ancient mythographers, including Diodorus Siculus, report figures from far fewer to as many as a hundred, with no single count treated as canonical.
Sources
- Hesiod, Theogony 313-318
- Apollodorus, Library 2.5.2
- Diodorus Siculus, Bibliotheca Historica 4.11
- Timothy Gantz, Early Greek Myth (1993)