#The Don'Rahj

The Don'Rajh are species of legendary sea serpents. They grow to colossal sizes, outlive most sapient species, and are utterly fearless, ruthless, predatory and intelligent.

##Biology

A Don'Rahj is a serpentine sea creature of up to 250 meters length and 25 meters diameter. They can be divided into three main parts; the head, the body, and the tail. Note: all sizes will be given for the largest Don'Rahj.

####Head.

The most obvious feature of the head is the great, four part maw. The four mandibles can be up to 10 meters in length, and are supported by skeletal bone. On the end of each mandible are a set of 4 steeply inwardly angled fangs, with the largest fang (~1m) closest to the end and the size of the fangs decreasing in size as they go along. These fangs are used to secure a hold on prey, and the mandibles are used to increase the area which it can attack and the size of prey it can hunt.

The mandibles have two joints, one elbow like, and one shoulder like. This allows them to extend directly away from the body, but also allows the Don'Rahj to pull any creature or foodmass caught in the fangs to the lampray like mouth that sits in the middle of its maw for ingestion. The lower quarter of each mandible is webbed with a cheek like muscle mass to make it easer to direct food to its mouth. The entire maw and mouth area is armoured with specially adapted scales and bone plate which prevent prey from harming it and have allowed the Don'Rahj to charge ships with impunity. The mandibles are shaped such that when closed, the front of a Don'Rahj is highly streamlined, but when open this vast maw directs water, air and prey into it.

The head lacks a true skull unlike the majority of fish or snakes, but rather has a small, highly armoured brain case at the connection between the top of the spine and the maw supports. Due to this, there are a number of interesting adaptations. Don'Rahj, have 2 large and highly eyes (~2m diameter) one on the side of its head, for better field of view. These eyes would be a vulnerable point on most creatures, but the Don'Rahj can actually retract them into its head for protection behind armoured plates or cause them to protrude nearly half their diameter for better field of vision. Another adaptation is instead of standard linear jaw muscles of most species, the mandibles, true mouth and beginning of the oesophagus have sphincter like constricting muscles along this length. This will grind and crush anything which enters the mouth against the many rows of teeth, ensuring even small prey are ready for digestion.

The Don'Rahj uses a wide array of sense organs to detect its prey. It has many combination smell/taste organs both internal to the maw and on the exterior of the head with which it can track prey, especially injured prey. Its eyes are very large, with very strong focus, and a sensitivity range which extends into the infra-red to track the paths of prey in cold oceans, especially at depth. It can orient them to provide near full angle vision, or to focus with binocular vision on prey (as long as the maw is closed). When in the final charge or at high speed or out of the water, it will usually retract its eyes and use other senses. The Don'Rahj do not have singular ears, but a number of senstive pressure organs along its length providing both excellent audio sensing, as well as highly accurate depth information. Finally, the Don'Rahj, much like sharks have passive electro-perception to aid detection of prey in waters where smell or vision would be near to useless.

####Body

The body is relatively cylindrical at first glance, with a slight ridge running along the spine. This ridge is actually highly developed muscle which pulls the ribs out into a much flatter and broader position, to providing a gliding surface. The skin is actually armoured hide, most often a dark grey / blue for camouflage as much as possible. The skin secretes a mucous which helps lubricate the armoured hide through the water, aiding its speed. The hide of old Don'Rahj will be highly scarred from fights with other Don'Rahj in establishing territory and mating rights.

The four fins are separated into two pairs based on their location and purpose. The dorsal and ventral fins protrude a relatively short distance and travel the length of the creature, merging at the tail which is large (> 30m tall x 60m long) and deeply forked. These fins are used for propulsion at low speeds, as the serpentine motion of the Don'Rahj forces these fins into the water. At high speeds, the body locks tight and the tail does the majority of the propulsion. The pectoral fins emerge just behind the head and are usually tucked tight into the body, extending approximately half to two thirds down the body.

When the Don'Rahj erupt out of the water, they will spread these spiny pectoral fins, giving them a very large gliding surface with which it can create large arcs through flocks of low flying birds or to attack surface prey from an unexpected angle. While it lacks any ability to provide propulsion to itself while out of the water, a Don'Rahj's high sprinting speed of up to 200km/h in the most powerful specimens allow for a very large vertical leap (150m) or an incredibly long distance glide in a shallower arc. This leaping out of the water is also a result of high speed charges against surface prey and is used often in sexual displays.

The main spinal joints allow for greater horizontal motion than vertical, causing the majority motion of the Don'Rahj to be sinuous, as well as causing the vertical tail.

The Don'Rahj have gills, but they are highly adapted, allowing the Don'Rahj to extract oxygen from sufficiently fast flowing air, which results in it using its maw like a jet intake when gliding.

The Don'Rahj have a double stomach digestive system. The first stomach is lined with teeth much like the mouth, and exists to grind all 'food', including plant material such as tree trunks into a fine slurry. The second stomach is highly acidic and filled with digestive enzymes which break down the food for absorption in the intestines. However, its excrement is highly nutritious to smaller organisms, causing the sea floors in Don'Rahj territories to be highly productive.

The Don'Rahj have multiple hearts, which all have a synchronised beat due to a equal length of nervous tissue linking each to the brain. This lets the Don'Rahj have much smaller hearts than a creature its size would require, as well as a much faster heart beat, something which aids its high speed sprints.