Over earths history, many creatures have evolved and thrived in the water, which allowed them to grow to massive proportions. The most notable of which you may know as Whales. The Whales were not the first animal to reach a large size and they certainly were not the last. Lets look at some of these Whale Mimics from the future:

The King-Gapemouth: descended from Razorbills, These are one of the first to fill a whale-like niche after the extinction of the Whales, at an impressive 30 million years in the future. Still with some vestigial remnants of their more bird-like past, including a similar body plan, they King-Gapemouths are of a modest size, 12-15 feet long. They hunt in packs of up to 5 and eat large invertebrates such as Mantasquid that have dominated over the fish since the fall of mankind. One of the most distinguishable traits of King-Gapemouths is the luxurious mane that they sport, seemingly only filling a sexual (along with popularity) purpose. Another key trait that distinguishes them from other Gapemouths is their strange convergent evolution of teeth. tough, yet flesh-derived bright-yellow hooks protrude from the roof of the mouth, and on the bottom a similar structure is seen, but derived from the tounge.

Fast forward a bit, and the birds fall out of power and the amphibians and reptiles rule the land. One amphibian descendant, which has had an catfish-like body structure for most of its evolutionary history after man, has dominated the oceans at a leisurely pace of 120 million years in the future. The original stock for this gentle giant was the salamander.

The Hux: The Hux is a large, eel shaped amphibian that has taken a filter-feeding lifestyle. Stretching 70 feet, this is by far the largest amphibian to ever exist. Its large protruding laws, with millions of filtering baleen, protrude out, and make up almost two fifths of its length. Its eyes have almost become fully vestigial, but it can still sense the environment around it by echolocation. Deep, echoing clicks and whirrs can often be heard by a Hux, making sure that there are no obstacles. Small protrusions of what was once limbs are now flippers to help it steer around the environment, although the main locomotion is done by two modified legs, now large and taken on a similar structure to the tails of cetaceans.

Now, after the age of birds, and the age of reptiles and amphibians, and after almost every age the earth will see of its fauna, there came one of the last ages of life: The age of invertebrates. The invertebrates had always dominated, albeit usually in small sizes, lurking in the background, waiting for their time to come. A mindbogglingly 500 million years in the future, the invertebrates started to take over the role of large-sized creatures. It would be another 200 million years before some strange, yet familiar forms arrived at the scene. Welcome to 700 million years in the future...

The Clasp-Jaws: Evolved from Mantasquids (which evolved from squids), the Clasp-Jaws have a very strange body plan. We start with a sleek, sausage shaped, orange and red body. At one end there is a gaping hole that the Clasp-Jaw uses to propel itself through the oceans using jet propulsion. Near the middle of the body there exists two steering fins on either side of the body, and a small, yet noticeable dorsal fin on top. Near the head, things get interesting. We find two large, front-facing eyes, which are used to take in as much light as possible in the murky depths of its habitat. At the mouth area, there exists jaws that are not dissimilar in shape to one of an army ant. These jaws almost double the length of the Clasp-Jaw, being 8 feet long. The entirety of the length of the Clasp-Jaw is about 20-25 feet, for comparison. These jaws clasp at unsuspecting prey (usually tuna-like shrimp) and then 4 manipulatory tentacles bring the limp food-item closer to the mouth.

The picture was made by as a commission for me, and I made the description: