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Review

Giraffe Stature and Neck Elongation: Vigilance as an Evolutionary Mechanism

Faculty of Life Sciences and Education, University of South Wales, Wales CF37 1DL, UK
Academic Editor: Chris O’Callaghan
Biology 2016, 5(3), 35; https://doi.org/10.3390/biology5030035
Received: 1 August 2016 / Revised: 2 September 2016 / Accepted: 7 September 2016 / Published: 12 September 2016
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 giraffe, vigilance of predators whilst feeding and drinking are important survival factors, as is the ability to interact with immediate herd members, young and male suitors. The evidence regarding giraffe vigilance behaviour is sparse and suggests that over-vigilance has a negative cost, serving as a distraction to feeding. In woodland savannah, increased height allows giraffe to see further, allowing each giraffe to increase the distance between its neighbours while browsing. Increased height allows the giraffe to see the early approach of predators, as well as bull males. It is postulated that the wider panorama afforded by an increase in height and longer neck has improved survival via allowing giraffe to browse safely over wider areas, decreasing competition within groups and with other herbivores. View Full-Text
Keywords: feeding giraffe; sexual selection; okapi; silvatherium; thermoregulation feeding giraffe; sexual selection; okapi; silvatherium; thermoregulation
MDPI and ACS Style

Williams, E.M. Giraffe Stature and Neck Elongation: Vigilance as an Evolutionary Mechanism. Biology 2016, 5, 35. https://doi.org/10.3390/biology5030035

AMA Style

Williams EM. Giraffe Stature and Neck Elongation: Vigilance as an Evolutionary Mechanism. Biology. 2016; 5(3):35. https://doi.org/10.3390/biology5030035

Chicago/Turabian Style

Williams, Edgar M. 2016. "Giraffe Stature and Neck Elongation: Vigilance as an Evolutionary Mechanism" Biology 5, no. 3: 35. https://doi.org/10.3390/biology5030035

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