heads have disproportionately evolved compared to the rest of their body, the heart has to pump harder in order for blood to reach the brain and through the neck. If the giraffe had evolved consistently throughout its body, it would not have characteristically higher blood pressure than most other animals. If Simmon's theory is true, there are also some basic assumptions that must take place. For example, males should only use their necks for intrasexual fighting, their necks should be longer and more muscular than females, males with larger necks should be dominant, and lastly, the fossil record should show disproportionate increases in neck size when compared with other body parts (Simmons 774).Various experiments were run to help to determine which theory has more basis within it. First of all, dissections were performed on a large sample of female and male giraffes that were over one year old. All the heads were cut at the same place and were weighed, and necks were cut at similar areas from the shoulder. When analyzing the results of the sexes, it becomes apparent that females have smaller skulls that contain less protection and their neck length is about 35 centimeters shorter than the average male. If neck length had evolved because of food competition it would not make sense that females would have shorter necks. Both sexes need to survive in order for the species to survive. As stated by Simmons, "for males and females each weighing 800 kilograms, the head masses would be 20.3 kg and 18.0 kg respectively and the neck masses would be 60 kg and 51 kg respectively" (Simmons 777). Another significant difference to note between the sexes is that while female head mass stops increasing at less than 22 kg, the male head mass continued to increase throughout their lives. Also, female neck length leveled off at 60 kg while the males reached weights of over 100 kg. This information also points out problems with Darwin's ...
