Water is not something most of us give much thought to. When we are thirsty, we turn on the tap or reach for a water bottle. But what do animals do when they are thirsty? Do animals need water to survive, and what happens if animals cannot find a safe water source?
Animals require water for hydration, metabolism, temperature regulation, respiration, and waste removal. Carnivores get water from their prey, while herbivores take their water from plants, and insects use the morning condensation to survive.
This article looks at why animals need water to survive and how they survive when water is scarce.
Do Animals Need Water To Survive?
All animals need water to survive. Here are a few key reasons why animals need water:
- Hydration: Water is crucial for maintaining the balance of fluids in an animal’s body. It is needed for basic physiological functions like digestion, circulation, and temperature regulation.
- Metabolism: Water plays a central role in various metabolic processes, including the breakdown of food for energy. Without water, these processes cannot occur efficiently.
- Temperature Regulation: Many animals use evaporative cooling, such as sweating or panting, to regulate their body temperature. This process relies on water to work effectively.
- Respiration: Oxygen transport in the body often relies on water-soluble molecules. Without sufficient water, respiration becomes compromised.
- Waste Removal: Water is necessary for the excretion of metabolic waste products from the body, primarily through urine.
Without water, all animals would begin suffering from eye conditions due to their eyes drying out. Water is essential for regulating body temperature, especially for endothermic (warm-blooded) animals. During digestion, water is required for efficient metabolic reactions to ensure the proper breakdown of food and absorption of nutrients.
A lack of water in the bowel can cause constipation, so a regular water source is vital to maintaining a healthy digestive tract.
Water helps to keep joints lubricated, so animals with a water deficit will begin to experience joint stiffness and other related conditions.
Blood is 94% water and is responsible for transporting oxygen and other substances around the body. A lack of water can slow these processes, reduce oxygen delivery to cells, and cause a dramatic change in blood pressure.
Water is vital for many bodily processes such as the secretion and absorption of hormones and enzymes throughout the body and the production of bodily fluids such as urine, saliva, and tears.
Without water, animals would not be able to produce saliva, which would create issues with swallowing. An animal could eventually starve to death due to their inability to swallow if they do not have access to water.
Water is everywhere on Earth and is needed for every animal to survive. Water can be found as a gas, liquid, or solid depending on the environment. Approximately 70% of the surface of the Earth is covered in water, and some organisms contain up to 90% water, with the human body holding 60% water.
Human brains are formed of 83% water, as are our kidneys. The heart and muscles around the body are approximately 75% water, and blood is even higher at 94%. On average, men carry around 5% more water in their bodies than women.
Water is a simple, naturally occurring solution made from one oxygen atom and two hydrogen atoms (H2O). Oxygen atoms have a negative molecular charge, while hydrogen atoms are positive. This causes water droplets to be attracted to one another.
All animals need water to survive, but some animals living in arid environments like deserts do not have access to water. Animals in dry habitats have adapted ways to store water for use during dry seasons or droughts.
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How Do Desert Animals Survive?
Desert animals have evolved a range of remarkable adaptations that allow them to survive in the harsh and arid conditions of deserts, where water and food resources are often scarce. Here are some common strategies and adaptations employed by desert animals.
Avoiding Heat
The easiest technique to adapt in the desert is to search for shade. The body uses less water if an animal can keep its body temperature low. Most desert animals are crepuscular, meaning they are active in the hours after sunset and before sunrise. Temperatures at these times are much cooler than they are during the day.
Gila monsters and rattlesnakes are both crepuscular. Reptiles are cold-blooded so avoiding the heat is vital as they use the environment’s temperature to regulate their body temperature. Even on a mild day in the desert, staying in the sun can quickly cause death due to heat exposure.
Smaller animals will dig burrows to avoid daytime temperatures. It is much cooler below ground, and many small mammals, most reptiles, and all desert amphibians use this technique.
Some desert animals will aestivate during the hottest hours of the day. Aestivation is similar to hibernation. An animal will enter a deep sleep where their heart and metabolic rates fall, bringing down their body temperature. Their reduced metabolic rate means they use less energy. Once the temperature cools, the animal will come around and be active.
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Water Retention
Desert toads will burrow into damp soil during the day, keeping their skin moist. Animals like vultures get most, if not all, of their water from their diet. Prey animals carry a lot of water in their blood and organs, sustaining a predator’s water requirement for some time.
Most reptiles and bird species excrete uric acid, removing waste from the body without losing too much water. Mammals, on the other hand, do not produce this. Instead, they produce urea, which contains a high volume of water.
Finding Water In The Desert
Most deserts do not have rivers or lakes, and those that do are only available during the short rainy season.
Many animals acquire water from their diet. The American badger has a varied diet of small mammals, lizards, birds, and eggs. All of these are vital sources of water as well as nutrition. They dig dens along desert river beds where the soil is soft, and the badger will stay underground during the hottest parts of the day.
Carnivores have access to plenty of water sources which they get from their prey, while herbivores get their water from desert plant life that has high water content. Plants use their long root systems to absorb water far below the surface. Fruits, seeds, and leaves from vegetation can also provide ample water for the many herbivorous mammals, reptiles, and amphibians found in North America’s deserts.
Some desert animals, such as the bobcat, have adapted to living near urban towns with plenty of water sources. Bobcats can often be seen drinking from garden ponds, man-made lakes on golf courses, and even puddles formed on pathways or rural sidewalks.
The desert bighorn sheep have adapted to living on the steep rocky mountainsides of North America’s deserts. At higher altitudes, the air holds more moisture, and vegetation can be found. Bighorns are very agile creatures and can navigate with ease. The plants they eat provide most of their water requirements, but they can be seen drinking from puddle formations when rain falls.
Desert insects find water collection much easier than larger animals. They tend to do most of their water sourcing at dawn and dusk. As water condenses in the air, the water droplets land on the ground or plant leaves. Insects and some other invertebrates, such as earthworms, will collect this water. As the temperature rises, the water droplets will eventually evaporate, so desert insects are more active around dawn and dusk.
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References And Further Reading
A Level Biology. (2016, December 9). The Biological Importance of Water. Retrieved from A-Level Biology: https://alevelbiology.co.uk/notes/the-biological-importance-of-water/
ACS Distance Education. (2021). Don’t Let Your Pets Be Thirsty! Retrieved from ACS Distance Education: https://www.acs.edu.au/Info/Pets/Pet-Care/water-needs.aspx
Gurera, D., & Bhushan, B. (2020). Passive water harvesting by desert plants and animals: lessons from nature. Philosophical Transactions Of The Royal Society A.
Hess, P. (2017, March 16). How some animals survive on almost no water. Retrieved from Popular Science: https://www.popsci.com/how-some-animals-survive-on-almost-no-water/
Schmidt-Nielson, K. (1965). Desert Animals: Physiological Problems of Heat and Water.