Meaning of a sentene

“the California newt’s display of its red underbelly is a clear warning that predators ignore at their peril


To me, “that” refers to the warning, so the boldface says predators ignore the warning because of their own good.

The meaning is totally nonsense to me.
I expected the sentence says something like that predators avoid the newt because of the warning.

Do I understand the sentence correct?

If you do something at you own peril, it may be dangerous for you you or may cause you problems.

If a predator decides to ignore the red underbelly of a newt and attacks it (newt), it may cause the predator harm.