Seaswimmers

Seaswimmers are creatures of the kingdom Carpozoa descended from the Speartooth Seaswimmer. Seaswimmers in general bear several similarities to snakes on Earth, but pursue a solely aquatic existence.

Anatomy
Seaswimmers have no limbs, like their limbless ancestors, and thus move by rippling their body. All seaswimmers have a forward-projecting tooth, used to stab at prey or in territorial fights, while in others, such as the Sanddigger Seaswimmer, it is used to dig up prey hidden in the sand. In some, this tooth has become a horn located farther up the head. They possess three eyes and four snorkel-like nostrils, and have a fluke at the end of their tails. Their skin is extremely streamlined, being very smooth in texture, and covers a layer of blubber that provides warmth. Some, like the Emperor Seaswimmer, are partially homeothermic.

Behavior
Some species of seaswimmers, such as the vicious seaswimmer, are pack hunters, but others hunt alone or in pairs.

Breathing and Blood
Seaswimmers still breathe air, and so need to surface every so often to breathe. Like all carpozoans, seaswimmers have red, iron-based blood.

Diet & Energy
All seaswimmers are carnivores, but hunt a wide range of prey due to their disparate niches.

Evolution
All seaswimmers are descended from the speartooth seaswimmer, itself descended from the slender spotted limbless. The first seaswimmers frequently ventured back onto land, but some, such as the emperor seaswimmer, have adapted to become nearly fully aquatic.

Locomotion
All seaswimmers swim by rippling their bodies in a serpentine fashion.

Reproduction
Seaswimmers reproduce sexually with two genders, and they give birth to live young. Most seaswimmers have to return to land to give birth, but a few species have adapted to give birth at sea.

Senses
Seaswimmers have three pairs of eyes, like their limbless ancestors. The Emperor Seaswimmer has modified sensory cells beneath its lower jaw which are highly sensitive to vibrations in the water.

Size
Most seaswimmers are around 50-170 centimeters (.5 to 1.7 meters) in length, but one species, the tumor seaswimmer, has grown to a massive size of nearly 4 meters through the evolutionary effects of shallows gigantism.