Spacewhales are called thus due to their whale-like size and shape. They roam the universe, feeding on whatever large amounts of matter they come across. They produce all the materials they need from the matter they collect. This matter is very large in size. They are of such a size that entire civilizations of intelligent beings, such as Cranium Rats, can form inside them. These species can live for billions of years before being fully digested by the host Spacewhale, during which time they can live off of their own ecosystem, with their primary energy source being the generation of the Spacewhale's body heat. Spacewhales are hyper intelligent, as they have developed a method to use the the combined knowledge of all beings within them, and utilize the unused parts of their minds for processing without their direct knowledge. The Spacewhales are highly dependent on their inner beings, for more than just intelligence and food. They also depend upon the intelligent beings for reproduction. Every civilization will inevitably create a massive biological entity once they are advanced enough. These entities will begin relatively small in size, but eventually all species and civilizations will collaborate, creating one or more massive self-sustaining parabiological entities. When this happens, the host Spacewhale will transfer enough of its own consciousness into the entity to give it the ability to learn and become like the Spacewhale. This is the host Spacewhale's offspring. The offspring will eventually grow to replace the 'parent' Spacewhale.

Spacewhales are never observed by humans simply because of their overwhelming size. Their size is beyond human comprehension, as humans themselves are part of a Spacewhale. Our particular Spacewhale is larger than most, its size being roughly the size of our known universe. Much phenomenon that is commonly associated with the Big Bang Theory are actually a result of the Spacewhale. A small amount of microwave radiation that can be detected from space at all times usually thought to be residue remaining from the Big Bang is actually one of the Spacewhale's many forms of communication. This specific information is actually in a form that will be interpreted in time, and lead the human race to build the parabiological entity that will be the Spacewhale's offspring. A Spacewhale has no other methods of communication known by mankind, as other communications are directed outward, toward other Spacewhales.

Spacewhales use all parts of their inner matter in their survival. They use the fusion energy from stars as a source of body heat, as well as the resultant material for other sorts of energy. They are, in essence, biological fusion power plants. Able to sustain energy for a theoretically infinite amount of time, as they are built to not release any energy. All energy is contained within them. The only energy ever released from a Spacewhale is in the process of its offspring replacing it. A relatively small amount of energy is released there, but ultimately gained back plus more with the Spacewhale consuming external matter.

Spacewhales, in the environment of their scale, are relatively docile to one another. They simply wander around, consuming matter, and never competing. Eventually, the amount of matter in the universe will simply run out, leaving just Spacewhales. At this point it is theorized that they will then become aggressive, attacking and destroying one another until there is just one supreme Spacewhale. This Spacewhale will become the only true being in the universe, all others are subdivisions of itself. At this point, all ambition will be removed from the Spacewhale, as there is no longer anything to compete for. As a direct result of that, ambition will be removed from all beings within it, and the many civilizations that once existed will be no more than simple nomads, living a peaceful life, unconcerned with the going ons of the universe. Eventually the supreme Spacewhale will lose connectedness with the beings in it, giving them supreme control of all their individual minds. Once this happens, the universe will go into a chaotic state, as each small individual will have the intelligence to level a god. This will continue until they break through the space whale, whether accidentally or intentionally. The Space will suddenly have the need to re-populate itself with more civilizations, and along with that need will come the need to reproduce. Due to the civilizations having a head start in the developing of technology, they will produce a large amount of Spacewhales from within the parent Spacewhale, which will repopulate the Spacewhale population and begin the whole cycle of Spacewhales all over again.