Relationship between dolphins and alien intelligence

Dolphin intelligence

Probably just me but I would be interested in getting other opinions about this, is there a similarity between the "grey" alien that is descibed in many abduction cases and dolphins?
Both considered intelligent life
Both are grey with big black eyes...

is it plausable that human kind was the creation of an Alien Intelligence and that one alien earth hybrid was a dolphin?

Just had a bit of a trippy dream about it and got it stuck in my head....

The Visitors claim to have lead previous existences as animals. Cetaceans are indeed very bright creatures,although forced to adapt to the ocean and frustrated they have no limbs.Just swim there.
The Visitors i have met have claimed to be cats,dogs,avians and hoofed creatures.
Strangely,no cetaceans.Just Poseidon who is very high up the ladder and has no physical form.