Last year, a test of cephalopod smarts reinforced how important it is for us humans to not underestimate animal intelligence. Cuttlefish were given a new version of the marshmallow test, and the results appeared to demonstrate that there’s more going on in their strange little brains than we knew.
https://www.sciencealert.com/cephalopods-can-pass-a-cognitive-test-designed-for-human-children