From Bruce Reidenburg:
The scientists are now exploring the layers of muscle on the sides of the whale. There is an interesting highly developed muscle that is special to the youngest baby whales. Since fetal whales are curled sideways in utero, this special adapted muscle unfolds the tail after the whale is born.
In people these muscles pull the back straight when standing. In the baby whale, this muscle is very powerful and becomes less developed as the animal ages. In humans, this is only one of a series of muscles that straighten the backwhen standing, so it is weak in baby humans and gets stronger as we learn to walk and run.
There is another interesting adaptation that is becoming visible during today’s dissection. The muscles of the abdominal wall involved in flexing ventrally are attaching to the broad non-respiratory ribs. In humans these muscles attach to the anterior part of the pelvis. In whales, these muscles are positioned to help propel the body wave during swimming. As we go deeper, we will find out what structures are tied to the whale’s small residual pelvis.