An allometric analysis of the giraffe cardiovascular system
There has been co-evolution of a long neck and high blood pressure in giraffes. How the cardiovascular system (CVS) has adapted to produce a high blood pressure, and how it compares with other similar sized mammals largely is unknown. We have measured body mass and heart structure in 56 giraffes of both genders ranging in […]
Scaling of the Appendicular Skeleton of the Giraffe (Giraffa camelopardalis)
Giraffes have remarkably long and slender limb bones, but it is unknown how they grow with regard to body mass, sex, and neck length. In this study, we measured the length, mediolateral (ML) diameter, craniocaudal (CC) diameter and circumference of the humerus, radius, metacarpus, femur, tibia, and metatarsus in 10 fetuses, 21 females, and 23 […]
Large predators and their prey in a southern African savanna: a predator’s size determines its prey size range
A long‐term (13‐year) data set, based on > 4000 kills, was used to test whether a sympatric group of large predators adheres to the theoretical predictions that (1) mean prey body size and (2) prey diversity increase as functions of predator body size. All kills observed by safari guides are documented routinely in Mala Mala Private Game […]
Growth patterns and masses of the heads and necks of male and female giraffes
We have analyzed the growth patterns of the head and neck of 65 male and 71 female giraffes from two different populations of giraffes, and also the dimensions of 19 different components of the head and neck in 8 female and 13 male giraffes, to establish if they showed sexual dimorphism and if sexual selection […]
Home range — body mass relations: a field study on African browsing ruminants
Home range data were collected concurrently from four syntopic browsing ruminant species in a conserved savanna ecosystem. Mean home range areas were: giraffe (Giraffa camelopardalis) 282 km^2; kudu (Tragelaphus strepciceros) 21.9 km^2; impala (Aepyceros melampus) 5.81 km^2; steenbok (Raphicerus campestris) 0.62 km^2. Home range area (Ahr) scaled on body mass (M) as: Ahr = 0.024 […]
On reconstructing Giraffa sivalensis, and extinct giraffid from the Siwalik Hills, India
Giraffa sivalensis occurred during the Plio-Pleistocene period and probably represents the terminal species of the genus in Southern Asia. The holotype is an almost perfectly preserved cervical vertebra of disputed anatomical location. Although there is also uncertainty regarding this animal’s size, other specimens that have been assigned to this species include fragments of two humeri, […]
Necks-for-sex or competing browsers? A critique of ideas on the evolution of giraffe
Recent years have witnessed a resurgence in tests of the evolution and origin of the great height and long neck of the giraffe Giraffa camelopardalis. The two main hypotheses are (1) long necks evolved through competition with other browsers allowing giraffe to feed above them (‘competing browsers’ hypothesis); or (2) the necks evolved for direct […]