Intelligence is a concept that's hard to define in an absolute; the border is rather fleeting.
Tool use? Repetition/learning of behaviour? Self-conscience (aka recognising yourself in a mirror)? Planning and teamwork? Sacrifice of the individual for the good of the tribe? Religion? Language/Speech? Writing/Art? Mathematics?

All of that can be found in various degrees and configurations over most of the animal kingdom. We've specialised in all of those, true; but compared to what might be, I'm not sure if we're even now truly intelligent.

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[Foot mouth in put]
Si tacuisses, philosophus mansisses.