It's actually quite difficult to define human intelligence. Every time we think we find something unique by humans eventually some animal turns up that can do it too. It may be all just a question of degree and how it's used.
(I'm no expert, so take that with a grain of salt.)
As does house finches: https://royalsocietypublishing.org/doi/full/10.1098/rspb.202...
Sperm whale codas exhibit contextual and combinatorial structure: https://www.nature.com/articles/s41467-024-47221-8
Ants have developed symbolic language: https://pmc.ncbi.nlm.nih.gov/articles/PMC10093743/
Everywhere we look close enough, we find life doing smart things.
Some great apes can learn to use symbols for communication. Bees can use specific dances to indicate direction and distance.
Starting from what should be considered "writing" to how to identify specific artifacts as abstract words.
Some researchers spend years in the forest studying one animal to isolate one single word they're speaking. Understanding other kind of intelligences is a crazy complex task.