Another point I was going to make CS.
Quote:
|
Originally Posted by WILLIAM
Christine,
You comment that there is no reason why a Sauropod's could not mate makes sense to me. It should not have been included in the writer's list of arguments. Perhaps sauropods were anatomically re-arrange to allow a different position. As soft tissue is not preserved in the fossil record, there is no data to answer a mating question.
The issue of blood pressure and the sauropod's ability to support its mass is a different question.
|
My Bold.
But it was included so I pointed it out. I don't think a different position would be the case for mating to happen.
As for blood pressure
HERE is an example of a giraffes way of coping.
Quote:
|
“To drive blood eight feet up to the head, the heart is exceptionally large and thick-muscled, and the blood pressure—twice or three times that of a man—is probably the highest in any animal” (Foster 409). “When a giraffe is standing in its normal erect posture, the blood pressure in the neck arteries will be highest at the base of the neck and lowest in the head. The blood pressure generated by the heart must be extremely high to pump blood to the head. But when the giraffe bends its head to the ground it encounters a potentially dangerous situation. It must lower its head between its front legs, putting a great strain on the blood vessels of the neck and head. The blood pressure plus the weight of the blood in the neck could produce so much pressure in the head that the blood vessels would burst. Mercifully, however, the giraffe is equipped with an adaptational package, including a coordinated system of blood pressure control. . . . Pressure sensors along the neck’s arteries monitor the blood pressure, and can signal activation of other mechanisms to counter any increase in pressure as the giraffe drinks or grazes. Contraction of the artery walls [which have increased muscle fibre toward the head], a shunting of part of the arterial blood flow to bypass the brain, and a web of small blood vessels (the rete mirabile, or ‘marvelous net’) between the arteries and the brain all serve to control the blood pressure in the giraffe’s head. Notice that adaptations require other adaptations so that a specialized organism such as the giraffe can function optimally” (Davis and Kenyon 71). The giraffe also has special “control valves in the jugular veins” (Foster 409); these “heavily valved veins control return of blood to the heart” (Davis and Kenyon 70).
|