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The giraffe’s long neck : From evolutionary fable to whole organism

A LONE GIRAFFE BULL STOOD at the edge of the scrubby bush forest that opened into a grassland. It was August, the beginning of spring, but also the middle of the dry season in the southern African savannah. The grasses and forbs were yellowed and brittle. Many trees and bushes had no leaves, though some still bore fruit, and others were just beginning to flower. The giraffe didn’t seem bothered by our presence, although we were off the main tourist track.

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Left Ventricular Morphology of the Giraffe Heart Examined by Stereological Methods

The giraffe heart has a relative mass similar to other mammals, but generates twice the blood pressure to overcome the gravitational challenge of perfusing the cerebral circulation. To provide insight as to how the giraffe left ventricle (LV) is structurally adapted to tackle such a high afterload, we performed a quantitative structural study of the LV myocardium in young and adult giraffe hearts. Tissue samples were collected from young and adult giraffe LV. Design-based stereology was used to obtain unbiased

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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 evolution of the long-necked giraffe can be reconstructed from fossils.” According to today’s best giraffe researchers, all fossil links that could show us the

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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 that exhibit unique genetic changes and likely contribute to giraffe’s unique features. Some of these genes are in the HOX, NOTCH and FGF signalling pathways,

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The structure of the masseter muscle in the giraffe (Giraffa camelopardalis)

In the giraffe (Giraffa camelopardalis), the masseter muscle was divided into several layers. The superficial and more medial (second) tendinous sheets of the masseter muscle fused with each other at the dorso-caudal part and a fleshy portion was located between these tendinous sheets. In the rostral part, the most superficial tendinous sheet turned around as a compact tendon and attached to the facial crest (Crista facialis). The turned tendinous sheet, however, never fused with the second tendinous sheet and this

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Umbilical cord stump retention and age estimation of newborn giraffes (Giraffa camelopardalis)

The umbilical cord stump is a conspicuous characteristic used to identify recently born giraffes (Giraffa camelopardalis) (Foster & Dagg, 1972; Langman, 1977; Leuthold & Leuthold, 1978; Pratt & Anderson, 1979; Pellew, 1981; Dagg & Foster, 1982). However, there is surprising disagreement over the length of time that the umbilical stump remains attached, with reports varying from about 4 weeks (Pellew, 1981; Serengeti, Tanzania: subsp. tippelskirchi) to 6 weeks (Leuthold & Leuthold, 1978; Tsavo East, Kenya: subsp. tippelskirchi) to 60 days

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Some uterine parameters in antelopes and a giraffe

Uteri of 69 African antelopes and a giraffe were morphologically examined and numbers of caruncles and their rows in each horn were recorded. Antelopes of subfamilies Taurotraginae, Aepycerotinae, Antilopinae, and Alcelaphinae had about 50 to 100 caruncles arranged in four rows in each uterine horn. Hippotraginae had about 100 to 200 caruncles in six to eight rows in each horn, and Reduncinae had about 10 to 20 caruncles in two rows in each uterine horn. The giraffe had about 70

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Gaits in mammals

In recent years there has been a great deal of published work on movements of various mammals, in particular, studies on the bone morphology and range of movements of joints, the muscle structure and places of muscle attachment, the physiology of muscle performance, the peculiarities of species as mechanical systems and the specific leg movements in the gaits of some common mammals — monkeys, cheetahs, dogs, horses and pecoran species. No comprehensive work on the gaits of mammals has been

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Ovarian and placental morphology and endocrine functions in the pregnant giraffe (Giraffa camelopardalis)

Gross, histological and immunocytochemical examinations carried out on maternal and fetal reproductive tissues from two pregnant giraffes at an estimated 8 and 13.5 months of gestation (term=15 months) revealed a typically ruminant macrocotyledonary placenta with binucleate trophoblast cells scattered sparsely in the placentome where they stained intensely with a prolactin antiserum. Binucleate cells were present in greater numbers in the intercotyledonary allantochorion where they did not stain for prolactin whereas the uninucleate trophoblast still did. A single large corpus luteum

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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 hypothesis in 17 male and 21 female giraffes with body masses ranging from juvenile to mature animals, by measuring head mass, neck mass, neck and

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