Two Riddles.

Sphinx was a monster that would eat
Whatever stranger she could get,
Unless his ready wit disclosed
The subtile riddle she proposed.

OEdipus was resolved to go
And try what strength of parts would do;
Says Sphinx, on this depends your fate;
Tell me what animal is that
Which has four feet at morning bright,
Has two at noon, and three at night?
'Tis Man, said he, who, weak by nature,
At first creeps, like his fellow-creature,
Upon all four; as years accrue,
With sturdy steps he walks on two;
In age at length grows weak and sick,
For his third leg adopts the stick.

Now, in your turn, 'tis just, methinks,
You should resolve me, Madam Sphinx,
What greater stranger yet is he
Who has four legs, then two, then three;
Then loses one, then gets two more,
And runs away at last on four?