PHYSIOLOGICAL & BEHAVIOURAL ADAPTATION OF CAMELS FOR HEAT REGULATION & WATER METABOLISM

Contents

  1. PHYSIOLOGICAL & BEHAVIOURAL ADAPTATION OF CAMELS FOR HEAT REGULATION & WATER METABOLISM
    1. Introduction
    2. Physiology of Accommodation:
      1. The Hoof of the Camel
      2. The Camel's Hump
      3. The Blood of the Camel
      4. The Udder
      5. The Urinary System
      6. The Digestive System
      7. Water Consumption
      8. Respiratory System
      9. Skin/Coat
      10. The Eye
      11. Skeleton
      12. Grazing
    3. Heat Regulation
    4. Water Preservation and Sweat Glands
    5. Kidney Function and Water Metabolism
    6. Water Metabolism in Stomach and Intestines
    7. Metabolic Water
    8. Salivary Glands and Water Metabolism
    9. Water Compensation
    10. References
      1. Bibliography
        1. Arabic References:
        2. English References:
      2. Figure Library

Introduction

Regardless of camels being highly associated with the middle east and Africa they have originated from north America about 45 million years ago (Cohen, 2013) from there on they have migrated great distances. The family of camelids consists: of the Dromedary, also known as the Arabian camel which is single humped; The Bactrian who is double humped ;The Alpaca, the Llama, the Vicuna, and the Guanaco. All species of the camel return to the specie of even toed ungulates called the Artiodactyl, and the suborder Tylopoda. The camelids play a crucial role in the life of the ancient Arabs who lived in the desert, the camel physiology matched perfectly to their harsh days, they suited their lives habitual and traveling wise. The camel stayed side by side of the desert peoples’ lives, resistant and generous in tough dry, and poor conditions, till the modern ways of transportation were invented. People relied on them for the sake of transport of heavy material from one area to another, they are also used for riding through long distances, nutritional reasons, for example camel hides, meat, skins, and furs and for entertaining reasons such as racing. Camels have proven to be the perfect desert animal due to its high produce of meat and milk compared to any other animal living there (El Amin, 1979).

Goal of the Research: To shine a light on the camel’s fascinating abilities in accomodation and survival to extreme dry climates.

Physiology of Accommodation:

The Hoof of the Camel

The Camel's Hump

The Blood of the Camel

The Udder

The Urinary System

The Digestive System

Water Consumption

Respiratory System

Skin/Coat

The Eye

Skeleton

Grazing

( الزروقي ومدني ،1992 )

Heat Regulation

The ability of the camel’s internal body temperature to change drastically but still maintaining homeostasis. They can cope with extremely hot days and very cold nights in the Arabian desert. Camels are heterothermic animals , depending on the light-cycle and also on the ambient temperature. During dehydration , the animal becomes poikilothermic. It must be noted that variation in body surface temperature and skin temperature is higher in the hump area compared to the underarm and flank areas. During the day , the camel stores in the heat energy which is then used during the cold nights. Heat regulation depends exclusively on evaporation on the body surface and not on increasing respiratory rate or panting which are absent in camelids.The fur of the camel is an efficient barrier against heat gain from the environment. During heat stress , the camel will initiate brain cooling since the brain consists of extremely sensitive tissues. This is done by the diversion of blood cooled by the nasal cavities which travel to the brain sinuses. In this way , venous blood cools down arterial blood of the carotid rete. This mechanism occurs during temperature changes of 33-45°C. It can thereby be concluded that myogenic vasoactive mechanism is the major means to heat regulation. (Elkhawad, 1992)

Water Preservation and Sweat Glands

The camel can tolerate water loss up to 30% of its body weight as compared to common mammals who can tolerate only 12% water loss. It must be noted that camels do not lose their appetite during dehydration unless extreme dehydration levels have been reached. It has been observed that when dehydrated camels are presented with water , they ingest a larger volume compared to the volume lost.Camels sweat directly from the skin surface as opposed to the hair surface since the former is much more effective and uses less energy. The excess water will be excreted 2-4 days later. Furthermore , the camel can drink one third of its body weight in water within 10 minutes without being intoxicated. In case of dehydration and high ambient temperature , camel reduce their fecal , urinary and sweating production. During dehydration periods , the kidneys reduce water losses both by decreasing the glomerular 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 (Kataria et al., 2001 A).

Kidney Function and Water Metabolism

The kidneys play a crucial role in the process of water balance inside the body, but they are not the only responsible organ for water excretion, the lungs, the skin and the digestive system also participates in this process. It has proven that the camel can go without water for three days with greenery present, and the amount of water that can be consumed from plants is approximately around 30 liters per day and during the colder months the camel does not drink large amount of water. Water consumption is dependent on the weather temperature during that season, the activity of the animal, and the amount of water present in the feed. Several studies have deduced that camels can go 30 days and a distance of 6000 kilometers without the present of water (Yagil et al.,1983.)

During the consumption of water, the absorption occurs in the mouth and the glands(?) due to the drinking receptors being present inside the mouth which get activated once water has entered the mouth, absorption also continues in the stomach and the intestines. The camel does not rely on water production from metabolic process especially in the cases of extreme thirst to avoid the heat production that occurs during metabolic process (Havez, 1968.)

The function of the kidney is absorbing as much as water so it can be returned into the body. In account to the amount of urine excreted in a thirsty camel is 0.001 of the camel’s weight per day while in thirsty goats it is 0.005 of their body weight per day which 5 times more of their body weight in comparison to the camel. The urine excreted in the camel is highly concentrated which is due to the anatomical feature of the kidneys having a high number of nephrons with longer loops of Henle in comparison to other animals, the longer length helps in a higher water absorption into the bloodstream. Studies have shown that the amount of water excreted by the urine decreases from 5 liters to 1.5 liters per day in the state of thirst. In addition to that it has been shown that the glomerular filtration decreased in the situation of lack of water by 75% meaning from 81 mL per kg to 22 mL per kg, and the amount of blood plasma into the kidney by 72%.Not only that but also the ability of the camel to concentrate its urine is due to kidney response to anti-diuretic hormone (Yagil, 1974).

Furthermore, the kidney is said to have higher amount of salt in its urine than the sea water when the camel’s diet is salty plants. The antidiuretic hormone is produced in the hypothalamus and is released into the bloodstream in response to increased levels of osmolarity.

Water Metabolism in Stomach and Intestines

Metabolic Water

Salivary Glands and Water Metabolism

Water Compensation

References

Bibliography

Arabic References:

English References:

Al-Baka, H. A. (2016). Camels and adaptation to water lack. MRVSA,(5), 64-69.

Ali, M. A., Adem, A., Chandranath, I. S., Benedict, S., Pathan, J. Y., Nagelkerke, N., . . . Kazzam, E. (2012). Responses to Dehydration in the One-Humped Camel and Effects of Blocking the Renin- Angiotensin System. PLoS ONE,7(5). doi:10.1371/journal.pone.0037299

Banerjee, S., & Bhattacharjee, R. C. (1963). Distribution of body water in the camel (Camelus dromedarius) [Abstract]. American Journal of Physiology-Legacy Content,204(6), 1045-1047. doi:10.1152/ajplegacy.1963.204.6.1045

Bouâouda, H., Achâaban, M. R., Ouassat, M., Oukassou, M., Piro, M., Challet, E., . . . Pévet, P. (2014). Daily regulation of body temperature rhythm in the camel (Camelus dromedarius) exposed to experimental desert conditions. Physiological Reports,2(9). doi:10.14814/phy2.12151

Cohen, J. (2013, March 05). Giant Ancient Camel Roamed the Arctic. Retrieved April 24, 2019, from https://www.history.com/news/giant-ancient-camel-roamed-the-arctic

Elkhawad, A. (1992). Selective brain cooling in desert animals: The camel (Camelus dromedarius) [Abstract]. Comparative Biochemistry and Physiology Part A: Physiology, 101(2), 195-201. doi:10.1016/0300-9629(92)90522-r

Ghoke, S. S., Jadhav, K. M., & Thorat, K. S. (2013). Assessing the Osmotic fragility of Erythrocytes of rural and semiurban Camels ( Camelus dromedarius ). Camel- International Journal of Veterinary Science,1(1), 75-78.

Haroun, E. (1994). Normal concentrations of some blood constituents in young Najdi camels (Camelus dromedarius). Comparative Biochemistry and Physiology Part A: Physiology,108(4), 619-622. doi:10.1016/0300-9629(94)90347-6

Nejat, S., Pirmoradian, M., Rashedi, M., & Nejat, S. (2016). Prevalence rate and composition of bladder stones in camel (Camelus dromedarius). Journal of Camel Practice and Research,23(1), 147. doi:10.5958/2277-8934.2016.00024.2

Schmidt-Nielsen, B., Schmidt-Nielsen, K., Houpt, T. R., & Jarnum, S. A. (1956). Water Balance of the Camel [Abstract]. American Journal of Physiology-Legacy Content,185(1), 185-194. doi:10.1152/ajplegacy.1956.185.1.185

Schmidt-Nielsen, B., Schmidt-Nielsen, K., Houpt, T. R., & Jarnum, S. A. (1957). Urea Excretion in the Camel [Abstract]. American Journal of Physiology-Legacy Content,188(3), 477-484. doi:10.1152/ajplegacy.1957.188.3.477

Schmidt-Nielsen, K., Schmidt-Nielsen, B., Jarnum, S. A., & Houpt, T. R. (1956). Body Temperature of the Camel and Its Relation to Water Economy [Abstract]. American Journal of Physiology-Legacy Content,188(1), 103-112. doi:10.1152/ajplegacy.1956.188.1.103

Solaiman, M. K. (2015). Functional Anatomical Adaptations of Dromedary (Camelus Dromedaries) and Ecological Evolutionary Impacts in KSA. International Conference on Plant, Marine and Environmental Sciences (PMES-2015) Jan. 1-2, 2015 Kuala Lumpur (Malaysia). doi:10.15242/iicbe.c0115058

Stone, H. O., Thompson, H. K., Jr., & Schmidt-Nielsen, K. (1968). Influence of erythrocytes on blood viscosity. American Journal of Physiology-Legacy Content,214(4), 913-918. doi:10.1152/ajplegacy.1968.214.4.913

Yagil, R., Etzion, Z., & Ganani, J. (1978). Camel thyroid metabolism: Effect of season and dehydration [Abstract]. Journal of Applied Physiology,45(4),

Figure Library