The Evolution of the Long-Necked Giraffe (Giraffa camelopardalis L.) – What Do We Really Know? (Part 2)
Introduction: The story which is commonly taught in high schools about the evolution of the long-necked giraffe by natural selection (feeding-competition-hypothesis) fails to explain, among other things, the size differences between males and females. Giraffe cows are up to 1.5 meters shorter than the giraffe bulls, not to mention the offspring. The wide migration range […]
The evolution of the long-necked giraffe (Giraffa camelopardalis L.) – What do we really know? (Part 1)
In the following article the assertions of three supporters of the synthetic theory concerning the evolution of the long-necked giraffe will be discussed: the statements of Ulrich Kutschera, Richard Dawkins and Kathleen Hunt. Ulrich Kutschera made the following statement regarding the origin of the giraffe, on 29 November 2005 in 3SAT (a German TV channel): […]
The cervical anatomy of Samotherium, an intermediate-necked giraffid
Giraffidae are represented by many extinct species. The only two extant taxa possess diametrically contrasting cervical morphology, as the okapi is short-necked and the giraffe is exceptionally long-necked. Samotherium major, known from the Late Miocene of Samos in Greece and other Eurasian localities, is a key extinct giraffid; it possesses cervical vertebrae that are intermediate […]
Giraffe genome sequence reveals clues to its unique morphology and physiology
The origins of giraffe’s imposing stature and associated cardiovascular adaptations are unknown. Okapi, which lacks these unique features, is giraffe’s closest relative and provides a useful comparison, to identify genetic variation underlying giraffe’s long neck and cardiovascular system. The genomes of giraffe and okapi were sequenced, and through comparative analyses genes and pathways were identified […]
Fossil evidence and stages of elongation of the Giraffa camelopardalis neck
Several evolutionary theories have been proposed to explain the adaptation of the long giraffe neck; however, few studies examine the fossil cervical vertebrae. We incorporate extinct giraffids, and the okapi and giraffe cervical vertebral specimens in a comprehensive analysis of the anatomy and elongation of the neck. We establish and evaluate 20 character states that […]
The remarkable anatomy of the giraffe’s neck
Mammalian cervical vertebrae 6 and 7 and thoracic vertebra 1 possess many distinguishing characteristics. In the giraffe, bone morphology, muscle origins and insertions, as well as the location of the brachial plexus (described as many osteological and some soft tissue characters) are identical to those in other mammals but are all displaced posteriorly by one […]
Sexual selection is not the origin of long necks in giraffes
The evolutionary origin of the long neck of giraffes is enigmatic. One theory (the ‘sexual selection’ theory) is that their shape evolved because males use their necks and heads to achieve sexual dominance. Support for this theory would be that males invest more in neck and head growth than do females. We have investigated this […]