Vascular system of giraffe
Both the discussions of the vascular system of the giraffe…mention venous valves, but both overlook the special ‘seried’ valves found at the entry of major tributaries into the axillary and brachial veins, though not into the jugular. Fewer occur in the closely-related okapi and some in jugular and femoral veins of the bactrian camel.
Robert Goetz: A pioneer of the study of the physiology of animals in the wild
Studying the physiology and behaviour of free-living wild animals was impossible until the technology to capture wild animals and to make measurements in the field was developed. A pioneer in this field was Robert H. Goetz who, having completed medical degrees in Germany and Switzerland, took up an appointment as a research scientist in the […]
Nasal heat exchange in the giraffe and other large mammals
The respiratory air of the giraffe is exhaled at temperatures substantially below body core temperature. As a consequence, the water content of the exhaled air is reduced to levels below that in pulmonary air, resulting in substantial reductions in respiratory water loss. Measurements under outdoor conditions showed that at an ambient air temperature of 24 […]
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 […]
Ovarian Ultrasonography Correlated with Fecal Progestins and Estradiol During the Estrous Cycle and Early Pregnancy in Giraffes (Giraffa camelopardalis rothschildi)
Fecal and urinary progestin analyses have shown that giraffes express a short reproductive cycle, averaging 15 days, compared with other large ruminants. However, actual ovarian events have not been correlated with the hormonal pattern. In this study, mature cycling female Rothschild giraffes (Giraffa camelopardalis rothschildi) were repeatedly examined by transrectal ultrasonography to correlate ovarian function […]
Harvey Cushing and the regulation of blood pressure in giraffe, rat, and man: introducing ‘Cushing’s mechanism’
The fundamental mechanism that underlies essential hypertension is a high total peripheral resistance. We review here possible origins of high total peripheral resistance in physiologically hypertensive giraffes, spontaneously hypertensive rats and humans with essential hypertension. We propose that a common link could be reduced brainstem perfusion, as first suggested by Cushing in 1901. Any tendency […]
Pressure profile and morphology of the arteries along the giraffe limb
Giraffes are the tallest animals on earth and the effects of gravity on their cardiovascular system have puzzled physiologists for centuries. The authors measured arterial and venous pressure in the foreleg of anesthetized giraffes, suspended in upright standing position, and determined the ratio between tunica media and lumen areas along the length of the femoral/tibial […]
Respiration and metabolism in the giraffe
Measurements have been made on respiration of three resting unstressed adult giraffe under normal conditions. Tracheal dimensions and body dimensions have also been measured in a large number of giraffe and other mammals. The results indicate that contrary to statements in the literature the giraffe does not have an abnormally large dead space, though the […]
Haemodynamics of the jugular vein in the giraffe
Controversy cotinues over the haemodynamics of the circulation to and from the head of the giraffe. The recent study by Hargens et al. provides new information explaining the absence of oedema in the legs of the ambulant giraffe. But in sedated, standing giraffes the pressure gradient down the jugular vein is about one-tenth of, and […]
The giraffe symbol of the African wilderness
An article overviewing giraffe evolution, ecology, reproduction, and population threats. Also discussed briefly the Veterinary Red Line fence and impacts on population movements.