scholarly journals The ship of the desert. The dromedary camel (Camelus dromedarius), a domesticated animal species well adapted to extreme conditions of aridness and heat

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 231 ◽  
Author(s):  
S. Bornstein

The dromedary camel (Camel dromedarius) is extremely well adapted to life in hot and arid lands. In terms of physiological adaptation to heat and water deprivation it surpasses by far every other large animal of which data have been collected. None of the adaptive mechanisms to cope with the environmental stresses are unique to the Arabian camel, but the efficiency of its adaptation is superior. At high ambient temperatures the camels adapt to the scarcity of water by reducing their faecal, urinary and evaporative water losses. During dehydration, the kidneys reduce water losses both by decreasing the glomerual filtration rate and by increasing the tubular reabsorption of water. Also their ability of regulating their body temperature from 34.5-40.7 °C conserves a lot of water, when most needed.

1978 ◽  
Vol 44 (5) ◽  
pp. 751-758 ◽  
Author(s):  
C. C. Barney ◽  
R. S. Elizondo

Prostaglandin E1 (PGE1) hyperthermia (fever) was studied at ambient temperatures (Ta) of 18, 27, and 35 degrees C in four male unanesthetized rhesus monkeys (Macaca mulatta) implanted with four guide tubes and one reentrant tube within the preoptic anterior hypothalamus (PO/AH). Rectal, hypothalamic, and mean weighted skin temperatures, O2 consumption, CO2 production, and respiratory and total evaporative water losses were measured continuously before and during PGE1 fever at each Ta. The febrile reponse to PO/AH PGE1 injection was dose responsive and was less at a Ta of 35 degrees C than at the other Ta's. At a Ta of 18 degrees C, fever was brought about primarily by an increase in metabolic rate. At a Ta of 27 degrees C, fever was produced by an increase in metabolic rate and by skin vasoconstriction. At a Ta of 35 degrees C, fever was the result of an increase in metabolic rate and a decrease in sweating evaporative heat loss. At each Ta some generalized skin vasconstriction also occurred. During the plateau phase of the fever, the measured heat losses and gains returned to near control levels. The data indicate that the rhesus monkey shows specific thermoregulatory responses to PO/AH PGE1 injection and would be a good model for the study of thermoregulation during fever in higher primates.


1979 ◽  
Vol 27 (2) ◽  
pp. 213 ◽  
Author(s):  
CK Williams

The four species of Australian chats differentially occupy arid regions and are considered to have problems of water balance during reproduction. They breed mainly during the winter semester, when ambient temperatures and vapour pressure deficit are lower and evaporative losses of body water are reduced. During a drought breeding is depressed; but chats breed opportunistically after abundant rainfall and exploit, by nomadism, the unpredictable rainfall in semiarid and arid Australia. The breeding season of the most mesic species, Epthianura albifrons, is reduced in the more xeric regions. In arid sympatric breeding areas the more xeric species have the more extended breeding seasons. Chats are territorial only during reproduction. The male protects the receptive female and the eggs and offspring, but not environmental resources. Territorial defence involves plumage pigmentation consistent with Gloger's rule, plumage patterns, postures and ritualized fighting displays. Territoriality and territorial behaviour are reduced in the more mesic species. This is consistent with relative rates of evaporative water loss, synchrony and apparent density of nesting, water requirements and physiological adaptation to aridity. A hypothesis is presented which suggests an adaptive hormonal mechanism relating to physiological adaptation to aridity and determining the different plumages.


1999 ◽  
Vol 202 (21) ◽  
pp. 3021-3028 ◽  
Author(s):  
T.C. Hoffman ◽  
G.E. Walsberg

We tested the hypothesis that birds can rapidly change the conductance of water vapor at the skin surface in response to a changing need for evaporative heat loss. Mourning doves (Zenaida macroura) were placed in a two-compartment chamber separating the head from the rest of the body. The rate of cutaneous evaporation was measured in response to dry ventilatory inflow at three ambient temperatures and in response to vapor-saturated ventilatory inflow at two ambient temperatures. At 35 degrees C, cutaneous evaporation increased by 72 % when evaporative water loss from the mouth was prevented, but no increase was observed at 45 degrees C. For both dry and vapor-saturated treatments, cutaneous evaporation increased significantly with increased ambient temperature. Changes in skin temperature made only a minor contribution to any observed increase in cutaneous evaporation. This indicates that Z. macroura can effect rapid adjustment of evaporative conductance at the skin in response to acute change in thermoregulatory demand.


2018 ◽  
Vol 315 (2) ◽  
pp. R165-R190 ◽  
Author(s):  
Annabel J. Sorby-Adams ◽  
Robert Vink ◽  
Renée J. Turner

Acute central nervous system injury, encompassing traumatic brain injury (TBI) and stroke, accounts for a significant burden of morbidity and mortality worldwide. Studies in animal models have greatly enhanced our understanding of the complex pathophysiology that underlies TBI and stroke and enabled the preclinical screening of over 1,000 novel therapeutic agents. Despite this, the translation of novel therapeutics from experimental models to clinical therapies has been extremely poor. One potential explanation for this poor clinical translation is the choice of experimental model, given that the majority of preclinical TBI and ischemic stroke studies have been conducted in small animals, such as rodents, which have small lissencephalic brains. However, the use of large animal species such as nonhuman primates, sheep, and pigs, which have large gyrencephalic human-like brains, may provide an avenue to improve clinical translation due to similarities in neuroanatomical structure when compared with widely adopted rodent models. This purpose of this review is to provide an overview of large animal models of TBI and ischemic stroke, including the surgical considerations, key benefits, and limitations of each approach.


Ecology ◽  
1966 ◽  
Vol 47 (4) ◽  
pp. 589-594 ◽  
Author(s):  
William R. Dawson ◽  
Vaughan H. Shoemaker ◽  
Paul Licht

Author(s):  
Juliana H. Giffoni ◽  
Raffaella B. C. Teixeira ◽  
Raphael R. Wenceslau ◽  
Melina A. F. Abrantes ◽  
Jéssica G. Oliveira ◽  
...  

2006 ◽  
Vol 54 (1) ◽  
pp. S302.4-S302 ◽  
Author(s):  
F. Tondato ◽  
L. Rougée ◽  
G. K. Ostrander ◽  
M. Ungs ◽  
M. M. Mower
Keyword(s):  

2015 ◽  
Vol 282 (1804) ◽  
pp. 20142781 ◽  
Author(s):  
Eran Levin ◽  
Brit Plotnik ◽  
Eran Amichai ◽  
Luzie J. Braulke ◽  
Shmulik Landau ◽  
...  

We report that two species of mouse-tailed bats ( Rhinopoma microphyllum and R. cystops ) hibernate for five months during winter in geothermally heated caves with stable high temperature (20°C). While hibernating, these bats do not feed or drink, even on warm nights when other bat species are active. We used thermo-sensitive transmitters to measure the bats’ skin temperature in the natural hibernacula and open flow respirometry to measure torpid metabolic rate at different ambient temperatures ( T a , 16–35°C) and evaporative water loss (EWL) in the laboratory. Bats average skin temperature at the natural hibernacula was 21.7 ± 0.8°C, and no arousals were recorded. Both species reached the lowest metabolic rates around natural hibernacula temperatures (20°C, average of 0.14 ± 0.01 and 0.16 ± 0.04 ml O 2 g −1 h −1 for R. microphyllum and R. cystops , respectively) and aroused from torpor when T a fell below 16°C. During torpor the bats performed long apnoeas (14 ± 1.6 and 16 ± 1.5 min, respectively) and had a very low EWL. We hypothesize that the particular diet of these bats is an adaptation to hibernation at high temperatures and that caves featuring high temperature and humidity during winter enable these species to survive this season on the northern edge of their world distribution.


1999 ◽  
Vol 276 (5) ◽  
pp. R1302-R1310 ◽  
Author(s):  
Christopher C. Barney ◽  
Gina L. Smith ◽  
Michael M. Folkerts

Spontaneously hypertensive (SH) rats and normotensive Wistar-Kyoto (WKY) rats were exposed to either 25 or 37.5°C for 3.5 h, and their thermal and water balance responses were compared. After exposure, either a blood sample was obtained or the rats were allowed to rehydrate for 4 h. SH rats had both higher core temperatures and evaporative water losses during heat exposure. Measurements of hematocrit, hemoglobin concentration, plasma protein and sodium concentrations, and plasma osmolality indirectly showed that the SH rats were dehydrated relative to the WKY rats after exposure to either 25 or 37.5°C. SH rats drank significantly more water but also had significantly higher urine volumes than the WKY rats and thus rehydrated only slightly better than the WKY rats. SH and WKY rats had similar levels of water intake and urine output after 24 h of water deprivation. The elevated thermal response of SH rats to heat exposure does not appear to lead to uncompensatable changes in body water status.


2017 ◽  
Vol 14 (2) ◽  
Author(s):  
Guilherme José da Silva e Sá

Abstract This article presents data collected in ethnographic research begun in 2014 at the Faia Brava Reserve in Portugal. The Faia Brava Reserve has been dedicated to ecological restoration by the association that manages it. This has made the reserve the starting point of an ambitious project for re-naturalizing the western region of the Iberian Peninsula, which foresees the reintroduction of large animal species in Portugal through its integration to the Rewilding Europe network. The article describes some of the steps necessary to the creation of re-naturalization areas, and some of the hypotheses associated to the re-naturalization project in Europe and particularly in Portugal.


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