Realistic Mer Biology Rambles
Ok so first of all, this post is gonna focus mainly on cetaceans (aka the family of whales and dolphins and all that jazz)Â
first of all, the textbook I’m reading says that the largest differences between living on land and living in water can be boiled into 6 points. Those being (1) not being able to breathe at all times, (2) increased rate of heat loss due to less/no fur, (3) relative weightlessness, (4) greater resistance to movement, (5) changed characteristics of sound propagation, (6) low light conditions in all but near surface waterÂ
second of all, looking at skeletal structures of ancestors of whales and a progression as time goes on, we can notice some of the main changes.Â
this is an image I found that shows what I’m talking about. some of the main changes is the elongation of the spine as the tail becomes more important in swimming.Â
The slow reduction of hind legs.Â
fusion of head and spine reducing head movementÂ
The nostrils slowly move up the head to eventually become the blow hole.Â
The body becomes streamlined to reduce drag in water.Â
Ability to hold breath for up to an hour in some species.
they can grow to such large sizes because they do not have to support their own body weight (relative weightlessness)
broad horizontal tail flukes powered by muscles to swim
dorsal fin to provide rotational stability (in some species of cetaceans)
Other things not visible, but also changed:
sophisticated sound processing systems Â
and I haven’t gotten to the chapter in my textbook that talks about this is detail yet, but they have a vascular heat exchange system to further remove heat loss
We can assume that some of this will apply to mer, or specifically mer that are based on cetaceans will have many of these adaptations.Â