Why the Calusas were hostile towards the Spanish

It's great when research comes together

In researching my upcoming novel Shame of Kings, I have found consistent evidence that the Calusas fiercely resisted the Spanish invaders. This began with their fight against Ponce De Leon, in which they hit him with a poison-tipped arrow that killed him.

This got me thinking about why the Calusas felt this way. Did they simply distrust foreigners or were they just aggressive by nature?

Both could be true, but I found two sources that may suggest something else.

First, I read that the Calusas may have been “forewarned” “about the approaching juggernaut of Spanish colonization” in this article by John E. Worth at the Randell Research Center, Florida Museum of Natural History.