> "What even is intelligence?"
to me, intelligence is simply the ability to discern (useful) connections between phenomena, basically being able to accurately inter-/extra-polate from observation through time and space, or alternatively, the ability to predict the future (for relatively finite values of future). it's kinda like the derivative of knowledge, and wit is the derivative of intelligence.
an IQ test measures a very narrow slice of that. it doesn't encompass humor, art, or sports/dance (dynamic/kinetic ability) for instance.
with dogs (or other pets), the intelligent part is their ability to parse your alien communications into desired responses, similar to learning a foreign language without an instructor, an interpreter, or a reference available.