Headscratchers / A Hat Full of Sky

How can the only emotion the Hiver feels be fear if it has nothing to fear?

One of the Hiver's characteristics is that the only emotion it can feel is fear. Fear arises when there is something to feel fear for. Fear arises when there is something of value that can be lost. We're all on the same page there, right? It is almost universally regarded that something has value if it:

• Gives pleasure (e.g.: A beautiful book)
• Reduces pain (e.g.: A hug on an abysmal day)
• Serves a perceived higher purpose (e.g.: God)

The Hiver can't feel pleasure; it has no pleasure to lose. The only pain it can feel is fear. But if we say that the Hiver fears that it can't end its pain, it goes in a circle: the reason for the fear is, bizarrely, the fear itself. It is too stupid to think about a higher purpose, with the exception of power when it is inside a host. This stems from fear, and that fear, as I have said before, is absurdly circular.
So... if the Hiver has nothing to lose, and fear arises because you have something to lose, then... how and why does the Hiver feel fear, exactly?
I apologize beforehand for not being the most articulate here. I also apologize for making the word "fear" sound like it's from an alien language.