Energy advantages of orientation to solar radiation in three African ruminants

Hetem, Robyn S.; Strauss, W. Maartin; Heusinkveld, B.G.; Bie, S. de; Prins, Herbert H. T.; Wieren, S.E. van

doi:10.1016/j.jtherbio.2011.07.012

Cited by 23 publications

(19 citation statements)

References 35 publications

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“…Recently, Hetem et al (2011) analyzed factors determining body orientation in three species of African ruminants -blue wildebeest (Connochaetus taurinus), eland (Tragelaphus oryx) and impala (Aepyceros melampus). Despite a rather limited data set, the study brought clear evidence for thermo-alignment in all three species -they oriented perpendicular to incident solar radiation during austral winter and parallel to incident solar radiation during austral summer.…”

Section: Thermo-alignment In Blue Wildebeest Eland and Impalamentioning

confidence: 99%

Magnetic alignment in mammals and other animals

et al. 2013

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a b s t r a c tMagnetic alignment (MA) constitutes the simplest directional response to the geomagnetic field. In contrast to magnetic compass orientation, MA is not goal directed and represents a spontaneous, fixed directional response. Because animals tend to align their bodies along or perpendicular to the magnetic field lines, MA typically leads to bimodal or quadrimodal orientation, although there is also growing evidence for a fixed unimodal orientation not necessarily coinciding with the magnetic cardinal directions. MA has been demonstrated in diverse animals including insects, amphibians, fish, and mammals. Alignment can be expressed by animals during resting as well as on the move (e.g. while grazing, hunting, feeding, etc.). Here, we briefly survey characteristic features and classical examples of MA and review the current knowledge about the occurrence of MA in mammals. In addition, we summarize what is known about mechanisms underlying MA and discuss its prospective biological functions. Finally, we highlight some physiological effects of alignment along the magnetic field axes reported in humans. We argue that the phenomenon of MA adds a new paradigm that can be exploited for investigation of magnetoreception in mammals.

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Section: Thermo-alignment In Blue Wildebeest Eland and Impalamentioning

confidence: 99%

Magnetic alignment in mammals and other animals

et al. 2013

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“…However, this orientation behavior decreases when there is a reliable source of water available (Maloney et al, 2005). Other African species, such as the eland, blue wildebeest, and impala also use preferential body orientations, positioning their bodies parallel to the sun in summer and perpendicular in winter (Figure 4) (Hetem et al, 2011). Once again, energetic demands drive these behaviors relative to the amount of direct solar radiation.…”

Section: Behavioralmentioning

confidence: 99%

Effects of Solar Radiation on Animal Thermoregulation

Norris¹,

Kunz²

2012

Solar Radiation

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“…Understanding how different species use thermoregulatory behaviors, such as orientation to solar radiation, to buffer changes in the thermal environment could help identify species vulnerable to climate change (Fuller, Mitchell, Maloney, & Hetem, ). Typically, behavioral thermoregulatory responses of mammals have been studied through visual observations by human observers (Alvarez, Guevara, Reyes, Sanchez, & Galindo, ; Fuller et al, ; Hetem et al, ; Lease et al, ; Treydte, Van der Beek, Perdok, & Van Wieren, ), a labour‐intensive and arduous process, and potentially biased in its outcome, because it is not possible to watch all individuals, or even index individuals, all the time. Moreover, the presence of a human observer may disrupt not just normal animal behavior (Jack et al, ; Klailova, Hodgkinson, & Lee, ; McDougall, ) but also autonomic function (Fuller et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…Blue wildebeest are more dependent on shade, whereas black wildebeest prefer open habitats with little to no shade available (Skinner & Chimimba, ). Both black (Lease et al, ; Maloney et al, ; Vrahimis & Kok, ) and blue wildebeest (Berry, Siegfried, & Crowe, ; Hetem et al, ) have been found to rely on orientation to solar radiation for thermoregulatory purposes. Both wildebeest typically orientate perpendicular to the sun early in the morning and late afternoon, especially in winter when ambient temperatures are cool, but in summer, and in the heat of the day, they orientate parallel to the sun (Berry et al, ; Hetem et al, ; Lease et al, ; Maloney et al, ; Vrahimis & Kok, ).…”

Section: Introductionmentioning

confidence: 99%

“…Such behavior presumably reduces the need for autonomic means of thermoregulation, such as sweating or panting (Bartholomew, 1964). Conversely, in cold environments, Alpine ibex bask in the morning to reduce metabolic costs of rewarming (Signer, Ruf, & Arnold, 2010) and blue wildebeest could save the energy equivalent of approximately 9% of their basal metabolic rate by orientating their bodies perpendicular to solar radiation instead of parallel during daylight hours (Hetem et al, 2011). The reliance of herbivores on solar orientation behavior as a thermoregulatory strategy can differ between closely-related species in the same environment (Lease, Murray, Fuller, & Hetem, 2014), and within species between different seasons (Hetem et al, 2011).…”

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Biologging subcutaneous temperatures to detect orientation to solar radiation remotely in savanna antelope

et al. 2019

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Observations of animal thermoregulatory behavior are labor‐intensive, and human presence may disturb the normal behavior of the animal. Therefore, we investigated whether a remote biologging technique could be used to detect orientation to solar radiation in savanna antelope. We predicted that when a mammal was orientated perpendicular to solar radiation, the subcutaneous temperature on the side of the body facing the sun would be greater than that on the opposite side, whereas when the mammal was orientated parallel to solar radiation, subcutaneous temperatures on both sides would be similar. A pilot study showed that the difference between left‐ and right‐side temperatures under a pelt reflected orientation to solar radiation if a pelt‐covered cylinder had been orientated for 15 min or longer. In addition, the rate of change in temperature difference could detect orientation that had changed within the previous 5 min. We implanted temperature‐sensitive data loggers subcutaneously into the flanks of eight black (Connochaetes gnu) and eight blue (Connochaetes taurinus) wildebeest. By incorporating both the rate of change and subcutaneous temperature differences and excluding times when wildebeest were lying down, our predictions correctly matched behavioral observations of wildebeest orientation to solar radiation 71% of the time. Our technique tended to fail when wildebeest were lying down, wind speeds were high and the sun was overhead. But those are conditions in which the benefits of manipulating orientation to solar radiation is of diminishing importance to a free‐living mammal. Therefore, subcutaneous temperatures provide physiologically relevant information on the importance of solar radiation to mammals.

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Energy advantages of orientation to solar radiation in three African ruminants

Cited by 23 publications

References 35 publications

Magnetic alignment in mammals and other animals

Magnetic alignment in mammals and other animals

Effects of Solar Radiation on Animal Thermoregulation

Biologging subcutaneous temperatures to detect orientation to solar radiation remotely in savanna antelope

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