Psychology Wiki

Assessment | Biopsychology | Comparative | Cognitive | Developmental | Language | Individual differences | Personality | Philosophy | Social |
Methods | Statistics | Clinical | Educational | Industrial | Professional items | World psychology |

Animals · Animal ethology · Comparative psychology · Animal models · Outline · Index

For water intaak in humns see water intake

Like humans animals are largely made up of water and must maintain their water intake.

Osmoregulation in animals

Kidneys play a very large role in human osmoregulation by regulating the amount of water reabsorbed from glomerular filtrate in kidney tubules, which is controlled by hormones such as antidiuretic hormone (ADH), aldosterone, and angiotensin II. For example, a decrease in water potential of blood is detected by osmoreceptors in hypothalamus, which stimulates ADH release from pituitary gland to increase the permeability of the wall of the collecting ducts in the kidneys. Therefore a large proportion of water is reabsorbed from fluid to prevent a fair proportion of water from being excreted.

A major way animals have evolved to osmoregulate is by controlling the amount of water lost through the excretory system.

Osmoregulation in protists

File:Paramecium contractile vacuoles.jpg

Protist Paramecium aurelia with contractile vacuoles.

Amoeba make use of contractile vacuoles to collect excretory waste, such as ammonia, from the intracellular fluid by diffusion and active transport. As osmotic action pushes water from the environment into the cytoplasm, the vacuole moves to the surface and disposes the contents into the environment.

Osmoregulation in bacteria

Prokaryotes respond via altered gene expression to changes in the osmotic environment. The model organism E. coli's osmoregulation is well described.

Vertebrate excretory systems

Waste products of the nitrogen metabolism

Ammonia is a toxic by-product of protein metabolism and is generally converted to less toxic substances after it is produced then excreted; mammals convert ammonia to urea, whereas birds and reptiles form uric acid to be excreted with other wastes via their cloacas.

Achieving osmoregulation in vertebrates

Four processes occur:

  • filtration — fluid portion of blood (plasma) is filtered from a nephron (functional unit of vertebrate kidney) structure known as the glomerulus into. Bowman's capsule or glomerular capsule (in the kidney's cortex) and flows down the proximal convoluted tubule to a "u-turn" called the Loop of Henle (loop of the nephron) in the medulla portion of the kidney.
  • reabsorption — most of the viscous glomerular filtrate is returned to blood vessels that surround the convoluted tubules.
  • secretion — the remaining fluid becomes urine, which travels down collecting ducts to the medullary region of the kidney.
  • excretion — the urine (in mammals) is stored in the urinary bladder and exits via the urethra; in other vertebrates, the urine mixes with other wastes in the cloaca before leaving the body (frogs also have a urinary bladder).



Water is needed by many birds although their mode of excretion and lack of sweat glands reduces the physiological demands.[1] Some desert birds can obtain their water needs entirely from moisture in their food. They may also have other adaptations such as allowing their body temperature to rise, saving on moisture loss from evaporative cooling or panting.[2] Seabirds can drink seawater and have salt glands inside the head that eliminate excess salt out of the nostrils.[3]




See also


  1. Engel, Sophia Barbara (2005). Racing the wind: Water economy and energy expenditure in avian endurance flight, University of Groningen.
  2. Tieleman, B.I. (January 1999). The role of hyperthermia in the water economy of desert birds. Physiol. Biochem. Zool. 72 (1): 87–100.
  3. Schmidt-Nielsen, Knut (1 May 1960). The Salt-Secreting Gland of Marine Birds. Circulation 21 (5): 955–967.

Further reading

  • Baenninger, R. (1968). Fighting by Betta Splendens; Effects on Aggressive Displaying by Conspecifics: Psychonomic Science Vol 10(5) 1968, 185-186.
  • Besch, N. F., & Van Dyne, G. C. (1967). Effects of Septal Lesions Varying in Locus and Size Upon Consummatory Behavior in the Rat: Psychonomic Bulletin 1(2) 1967, 25-26.
  • Boice, R., & Boice, C. (1968). Water Intake Following Capture and Deprivation in Southwestern Rodents: Psychonomic Science Vol 12(3) 1968, 104.
  • Bolles, R. C. (1968). Anticipatory General Activity in Thirsty Rats: Journal of Comparative and Physiological Psychology Vol 65(3, Pt 1) Jun 1968, 511-513.
  • Carey, R. J. (1967). Independence of Effects of Septal Ablations on Water Intake and Response Inhibition: Psychonomic Science Vol 8(1) 1967, 3-4.
  • Cohen, J. S., & Stettner, L. J. (1968). Effect of Deprivation Level on Responses to Novel Alleys in Albino Rats: Psychonomic Science Vol 11(3) 1968, 103-104.
  • Collier, G., Levitsky, D., & Weinberg, C. (1968). Body Weight Loss as a Measure of Motivation in Thirsty Guinea Pigs: Psychonomic Science Vol 10(1) 1968, 27-28.
  • Corbit, J. (1967). Effect of Hypervolemia on Drinking in the Rat: Journal of Comparative and Physiological Psychology Vol 64(2) Oct 1967, 250-255.
  • Coury, J. N. (1967). Neural Correlates of Food and Water Intake in the Rat: Science 156(3783) 1967, 1763-1765.
  • Coury, J. N. (1967). Neural Correlates of Food Intake in the Rat: Dissertation Abstracts International.
  • Crow, L. T. (1968). Maintenance and Measurement of Water-Regulatory Variables through Controlled Feeding: Psychological Reports 22(3, PT 3) 1968, 1125-1128.
  • Dufort, R. H. (1967). Water Intake of the Rat with Food Present Following Different Durations of Water Deprivation: Psychological Reports 20(1) 1967, 146.
  • Essig, C. G. (1968). Increased Water Consumption Following Forced Drinking of Alcohol in Rats: Psychopharmacologia 12(4) 1968, 333-337.
  • Fuller, J. L., & Cooper, C. W. (1967). Saccharin Reverses the Effect of Food Deprivation Upon Fluid Intake in Mice: Animal Behaviour 15(4) 1967, 403-408.
  • Hatton, G. I., & Almli, C. R. (1967). Learned and Unlearned Components of the Rat's Adaptation to Water Deprivation: Psychonomic Science Vol 9(11) 1967, 583-584.
  • Hawkins, T. D. (1967). Effects on Schedule-Induced Polydipsia and Variable-Interval Bar-Press Performance: Psychonomic Bulletin 1(2) 1967, 34.
  • Hsiao, S. (1967). Saline Drinking Effects on Food and Water Intake in Rats: Psychological Reports 21(3) 1967, 1025-1028.
  • Hsiao, S., & Rasmussen, C. (1968). Why Does a Variety of Measures of Thirst Yield Different Results? an Explanation Developed by Studying the Effect of an Aversive Factor on Liquid Intake of Rats: Psychonomic Science Vol 10(3) 1968, 97-98.
  • Hulse, S. H. (1967). Licking in Rats: Some Effects of Stimulus Intensity on the Unconditioned Reflex: Psychonomic Bulletin 1(2) 1967, 34.
  • Hunt, G. L., Jr., & Smith, W. J. (1967). Pecking and Initial Drinking Responses in Young Domestic Fowl: Journal of Comparative and Physiological Psychology Vol 64(2) Oct 1967, 230-236.
  • Irwin, S., Banuazizi, A., Kalsner, S., & Curtis, A. (1968). One Trial Learning in the Mouse: I. Its Characteristics and Modification by Experimental-Seasonal Variables: Psychopharmacologia 12(4) 1968, 286-302.
  • Jackson, D. E. (1967). Excessive Drinking in the Rat: Excessive or Normal? : Psychological Reports 20(3, PT 1) 1967, 740.
  • Kakolewski, J. W., Cox, V. C., & Valenstein, E. S. (1968). The Consumption of a Saccharin-Glucose Solution by Satiated and Food-Deprived Immature Rats: Psychonomic Science Vol 11(9) 1968, 317-318.
  • Kissileff, H. R. (1967). The Control of Water Intake in the Rat Recovered from Lateral Hypothalamic Lesions: Dissertation Abstracts International.
  • Kutscher, C. (1967). Inhibition of Drinking in Thirsty Rats by Food Deprivation: Measures of Potential Internal Stimuli: Proceedings of the Annual Convention of the American Psychological Association 2 1967, 113-114.
  • Kutscher, C. L., Stillman, R. D., & Weiss, I. P. (1968). Food-Restriction Polydipsia in Hamsters: Psychonomic Science Vol 11(7) 1968, 243-244.
  • Lubar, J. F., Boyce, B. A., & Schaefer, C. F. (1968). Etiology of Polydipsia and Polyuria in Rats with Septal Lesions: Physiology & Behavior 3(2) 1968, 289-292.
  • Macphail, E. M. (1968). Effects of Intracranial Cholinergic Stimulation in Rats on Drinking, Eeg, and Heart Rate: Journal of Comparative and Physiological Psychology Vol 65(1) Feb 1968, 42-49.
  • McFarland, D. J. (1967). Phase Relationships between Feeding and Drinking in the Barbary Dove: Journal of Comparative and Physiological Psychology Vol 63(2) Apr 1967, 208-213.
  • Mietkiewski, K., & Kozik, M. A. (1967). Neurosecretory Activity of Rabbit Hypothalamic Nuclei after Insulin Shock: Polish Endocrinology 18(3-4) 1967, 127-138.
  • Miles, R. C. (1967). Effects of Extreme Deprivation on Probability and Rate Measures of Learned Performance: Psychonomic Bulletin 1(2) 1967, 34.
  • Miller, N. E., & Carmona, A. (1967). Modification of a Visceral Response, Salivation in Thirsty Dogs, by Instrumental Training with Water Reward: Journal of Comparative and Physiological Psychology Vol 63(1) Feb 1967, 1-6.
  • Mogenson, G. J., & Stevenson, J. A. (1967). Drinking Induced by Electrical Stimulation of the Lateral Hypothalamus: Experimental Neurology 17(2) 1967, 119-127.
  • Morrison, S. D. (1968). Regulation of Water Intake by Rats Deprived of Food: Physiology & Behavior 3(1) 1968, 75
  • Morrow, J. E., & Smithson, B. L. (1968). Learning in an Invertebrate with a Positive Reinforcement of Water: Psychological Reports 22(3, PT 2) 1968, 1203-1204.
  • Owings, D. H., Haerer, H. A., & Lockard, R. B. (1967). Sucrose Intake Functions of Rat and Cockroach for Single and Six Solution Presentations: Psychonomic Science Vol 7(3) 1967, 125-127.
  • Parker, S. W., & Feldman, S. M. (1967). Effect of Mesencephalic Lesions on Feeding Behavior in Rats: Experimental Neurology 17(3) 1967, 313-326.
  • Phillips, A. G., & Mogenson, G. J. (1968). Effects of Unilateral Hypothalamic Lesions on Drinking and Self-Stimulation in the Rat: Psychonomic Science Vol 10(9) 1968, 307-308.
  • Pizzi, W. J., & Lorens, S. A. (1967). Effects of Lesions in the Amygdalo-Hippocampo-Septal System on Food and Water Intake in the Rat: Psychonomic Science Vol 7(5) 1967, 187-188.
  • Reynierse, J. H., & Spanier, D. (1968). Excessive Drinking in Rats' Adaptation to the Schedule of Feeding: Psychonomic Science Vol 10(3) 1968, 95-96.
  • Salzberg, C. L., Henton, W. W., & Jordan, J. J. (1968). Concurrent Water-Drinking on Fi and Crf Food-Reinforcement Schedules in the Rhesus Monkey: Psychological Reports 22(3, PT 2) 1968, 1065-1070.
  • Sengstake, C. B. (1968). Habituation and Activity and Patterns of Rats with Large Hippocampal Lesions under Various Drive Conditions: Journal of Comparative and Physiological Psychology Vol 65(3, Pt 1) Jun 1968, 504-506.
  • Singh, D., & Meyer, D. R. (1968). Eating and Drinking by Rats with Lesions of the Septum and the Ventromedial Hypothalamus: Journal of Comparative and Physiological Psychology Vol 65(1) Feb 1968, 163-166.
  • Spigel, I. M., & Ellis, K. R. (1967). Electrolyte Balance and Deficit-Drinking in a Reptile: Psychonomic Bulletin 1(2) 1967, 26.
  • Spigel, I. M., & Ellis, K. R. (1968). Electrolyte Balance and Deficit Drinking in a Reptile: Journal of Comparative and Physiological Psychology Vol 65(3, Pt 1) Jun 1968, 384-387.
  • Spigel, I. M., Ellis, K. R., & Kaiser, Y. E. (1967). Electrolyte Balance and Drinking in the Fresh Water Turtle: Journal of Comparative and Physiological Psychology Vol 64(2) Oct 1967, 313-317.
  • Umemoto, M., & Kido, R. (1967). Depressing Effect of Methamphetamine on Self-Stimulation in the Cat: Nature 216(5122) 1967, 1333-1334.
  • Vance, W. B. (1967). Sodium Thirst in Nephrectomized and Nephrectomized-Anosmic Rats: Psychonomic Science Vol 9(5) 1967, 301.
  • Vance, W. B. (1967). Water Intake of Hyposalemic Anosmic Rats: Psychonomic Science Vol 9(5) 1967, 297-298.
  • Vilar, A. N., Gentil, C. G., & Covian, M. R. (1967). Alterations in Sodium Chloride and Water Intake after Septal Lesions in the Rat: Physiology & Behavior 2(2) 1967, 167-170.
  • Werboff, J., & Anderson, A. (1967). Vibrissae and Genetic Background: Their Role in a Water Submersion Task with Mice: Perceptual and Motor Skills 24(3, PT 2) 1967, 1143-1153.