Alien Vs Predator

The Yautja circulatory system can be divided in to 3 circulations:

• 1. From the heart to the lungs
• 2. From the heart to the body
• 3. From the heart to the brain

In the Yautja circulatory system the brain has a separate circulation. This allows for a higher blood pressure in the rest of the body without damaging the fine network of blood vessels in the brain. This allows the Yautja to live with blood pressures that would normally kill a human.

The ability to create and survive such high blood pressure has certain advantages. The blood can be transported through the body faster and thus oxygen and other nutrients are transported quicker and waste products are removed faster.
This special circulatory system is part of why Yautja are so strong. It allows the organs and muscles to work harder and thus increase the muscles capacity.

The Yautja 5-part heart consists of 2 auricles and 3 ventricles. The blood is pumped from the right side of the heart (seen on the left of the heart schematic in blue) through the lungs. From there it goes back to the heart and into the left auricle (seen on the right of the heart schematic in green). From here it goes in to the 2 ventricles that are connected to it. One pumps it into the body and the other pumps it into the brain at a much lower pressure. When the blood has gone through the body and the brain it goes back to the right side of the heart and the cycle starts again.
The Yautja skeleton is stronger than our own, although the material it's made of isn't stronger than the material our own bone is made of. The yautja skeleton is stronger however because of its firm build. The bones are much thicker than our own and also much more compact which makes them heavier.

Yautja don't seem to have the problem of calcification which makes bones more fragile. This is partially because the oxygen rich blood allows the bones to reinforce their structure naturally, and also because their body uses more carbon in making the bone which makes it just as flexible as, and stronger than, human bone tissue, but about 3-4 times more dense and 5-6 times more heavy.

The reason Yautja are much stronger is due partially to the fact that the muscles have a much more efficient nutrient and waste product transport, as well as the much higher gravity on there home planet, And that the muscle fibers are prismoidal and triangular as opposed to a humans round muscle fibers. This makes more muscle able to fit in the same amount of space, and due to the larger size attributes to the greater strength.

The greater strength is also created by the higher percentage of muscular tissue per kg of body weight and the fact that Yautja are bigger then humans.

The Yautja nervous system is almost a replica of human nerves other than DNA and a few structural changes. The nerves use a form of organic fiber optics that allow chemical and electrical signals to travel at speeds up to 20 times faster than a human. Also instead of remaining relatively close enough for signals to take place, the nerve endings grow past eachother and intertwine, allowing for much faster communication.

An interesting thing of the Yautja is their unique DNA structure. Instead of a double helix, The yautja have a triple helix dna form. the advantages and disadvantages of this are unknown. Also instead of 4 base pairs like humans, they have 5 base pairs in their DNA. These differences may have unknown advantages or disadvantages.