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Giraffe Evolution: Two Popular Stories

The giraffe (Giraffa camelopardalis) is a marvelous animal, better known than its forest-dwelling relative the okapi and countless other charismatic artiodactyls in large part due to its proportions. As a result, there has been no shortage of speculation about the origins of the giraffe’s iconic neck. Making things up about giraffes is a well-established tradition: Timotheus of Gaza (~500 CE) reports that “the giraffe is an Indian animal; and it is born from the intercourse of different animals” (presumably a

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Giraffe Stature and Neck Elongation: Vigilance as an Evolutionary Mechanism

Giraffe (Giraffa camelopardalis), with their long neck and legs, are unique amongst mammals. How these features evolved is a matter of conjecture. The two leading ideas are the high browse and the sexual-selection hypotheses. While both explain many of the characteristics and the behaviour of giraffe, neither is fully supported by the available evidence. The extended viewing horizon afforded by increased height and a need to maintain horizon vigilance, as a mechanism favouring the evolution of increased height is reviewed. In

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Zoo Foraging Ecology: Preference and Welfare Assessment of Two Okapi (Okapia johnstoni) at the Brookfield Zoo

Applying principles of foraging ecology to zoo-housed animals can positively influence animal behavior, and assist with evaluating exhibit space and design. In this study, we implemented zoo foraging ecology by measuring giving-up densities (GUDs) in food patches to address several welfare-related questions with captive okapi (Okapia johnstoni). Our objectives were to: (1) determine whether food patches can reveal how the individual animals perceive their exhibit space (i.e., areas of preference and aversion; landscapes of comfort); and (2) determine whether implementation

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A Multi-Institutional Assessment of Factors Influencing Locomotion and Pacing in Captive Okapis (Okapia Jonhstoni)

The okapi (Okapia johnstoni), native to the Democratic Republic of Congo, is a large, solitary, and diurnal forest-dwelling ungulate highly sensitive to captive conditions. The captive population demonstrates persistent health problems, reproductive abnormalities, and several potentially abnormal repetitive behaviors. This study reports on locomotion and pacing in adult male and female okapis. Commonly, data on repetitive behavior have been derived from surveys. Although insightful, the results are often highly generalized and provide little information about the true preponderance and nature

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Giraffe and okapi: Africa’s forgotten megafauna

The Giraffidae family includes only two living species of ungulates: the giraffe (Giraffa camelopardalis) and the okapi (Okapia johnstoni), both restricted to the African continent. Taxonomically, the Giraffa and Okapia genera separated from each other approximately 16 million years ago (Hassanin et al., 2012), and they now exhibit as many differences as similarities. Today Okapia is represented by one species (Okapia johnstoni; Hart, 2013), though with surprisingly high genetic variation (Stanton et al., 2014), whereas nine subspecies of giraffe are

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The binucleate cell of Okapi and Giraffe placenta shows distinctive glycosylation compared with other ruminants: A lectin histochemical study

The placenta of ruminants contains characteristic binucleate cells (BNC) with a highly conserved glycan structure which evolved early in Ruminant phylogenesis. Giraffe and Okapi placentae also contain these cells and it is not known whether they have a similar glycan array. We have used lectin histochemistry to examine the glycosylation of these cells in these species and compare them with bovine BNC which have a typical ruminant glycan composition. Two placentae, mid and near term, from Giraffe (Giraffa camelopardalis) and

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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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Understanding selection for long necks in different taxa

There has been recent discussion about the evolutionary pressures underlying the long necks of extant giraffes and extinct sauropod dinosaurs. Here we summarise these debates and place them in a wider taxonomic context. We consider the evolution of long necks across a wide range of (both living and extinct) taxa and ask whether there has been a common selective factor or whether each case has a separate explanation. We conclude that in most cases long necks can be explained in

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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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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 in the evolutionary elongation of the neck. We describe detailed anatomical features of the cervicals of S. major, and compare these characteristics with the vertebrae

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