[HarleyD]

Whoever calls on the name of the Lord shall be saved.

Correct, but let us not forget...

Rom 1:19 For what can be known about God is plain to them, because God has shown it to them.
Rom 1:20 For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse.
Rom 1:21 For although they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened.
Rom 1:22 Claiming to be wise, they became fools,

As far as Nineveh, it was the Lord who made the effort to bring Nineveh to repentence-even against the wishes of Jonah.

[xzins]

The important part is that he called for them. And even the animals.