It may be thought of as a symbol of rebirth. This snake features strongly in Aztec religion
It comes from Aztec mythology. The Aztec traveled across Mexico until they came upon the the symbol because they're gods had for told it.
an eagle perched atop a cactus with a long snake in its beak.
they bite a snake
a symbol of a snake is symbol for charm, danger and sexual energy
The eagle
It is a snake
what is a african symbol for strength?
If you mean the coat of arms found on the Mexican flag, it consists of a golden eagle atop a cactus, devouring a snake. It is part of an Aztec prophecy. See the related questions for further details.
War symbol
Because the snake was associated with her by virtue of it being a symbol of rebirth in nature and the fertility of the earth.
Slytherin's animal symbol is a snake/serpent.