We can assume cetaceans are sentient beings based on many factors that indicate they think, communicate, and are biologically capable of "Knowing" what they are....but this "God" thingy apparently did not create them in it's image.
By the way...where do you fit gravity into your assumed measurements of mass.
Furthermore that fact that, as you have pointed out, that sentient beings think, communicate and are capable of knowing what they are, is evidence that they have been created by a superior sentience that thinks, communicates, and is capable of knowing what it is. It is not an unreasonable assumption at all.
And with regards to gravity, that is also based on the assumption that there is a force called gravity that is directly proportional to the product of an object with a mass of A, another object with a mass of B, and is inversely proportional the squared distance between the two objects. That is what Newton assumed and it is known as Newton's law of gravitation.
We regularly see, feel, and manipulate the forces of gravity and mass....the only things we see from God, might be faith healing.
I think we all know how that works out in the end.
Furthermore things like the force of gravity are the indirect effects of the energy of God. But we can measure the direct effects of God's divine energy by observing how that energy effects sentience in the form of divine qualities, such as tolerance, mercy, an absence of the conception that others are enemies, cleanliness, self control, and truthfulness. Jesus exhibited these qualities to a very high degree and therefore, we can understand that he was indeed motivated, under the influence if you will, of a very pure type of love of God.