Animal Information

Urine, Urates, Uric Acid, Nitrates. A WASTE Product but not a WASTE of Time.

Urate: A salt derived from uric acid. When the body cannot metabolize uric acid properly, urates can build up in body tissues or crystallize within the joints.

The normal feces of a tortoise consists of fecal substance. This usually arrives as an odiferous formed mass consisting of the end products of digestion. In fact, the color, consistency, and volume of the feces will vary depending on what the tortoise is ingesting. But for the most part, the feces will be brown or greenish-brown if the diet is proper.

Click to read our page that talks about Grasses, Flowers, Weeds, and Hay Are More Important Than Produce to read more about the proper diet for tortoises.

Tortoises also produce urine and urates. Urine is the liquid portion stored in the urinary bladder. Urine contains waste products and toxins that are filtered from the bloodstream.

Reptiles also have one more type of excretion product, called urates or uric acid. This is the end product of protein digestion and is also stored in the urinary bladder as a creamy, off-white pasty semi-solid.

In reptiles, uric acid is cleared from the bloodstream by the kidneys.

Tortoises convert this ammonia to uric acid, which is less toxic to the bladder wall and lets them hold water in their bladder for long periods of time.

Tortoises that are desert species have adapted to their arid environment. They can recycle water from their bladder into their system when they do not have access to drinking water.

When the tortoise urinates, it will pass the liquid urine and the semi-solid urates at the same time.

A tortoise may urinate and defecate at the same time, which may leave urate deposits on the fecal material. This will make the feces appear as if it is white or off-white.

If the uric acid builds up in high enough levels, the uric acids combines with electrolytes like sodium, calcium, and potassium, to form urates.

Uric acid contains four nitrogen atoms, in which, only a small amount of water is needed for its excretion.

Check out this video where we share more about this important process….

Out of solute, it precipitates and forms crystals. The enzyme xanthine oxidase makes uric acid from xanthine and hypoxanthine, which in turn are produced from other purines. Xanthine oxidase is a large enzyme whose active site consists of the metal, molybdenum, bound to sulfur and oxygen. Uric acid is released in hypoxic conditions.

In a well-hydrated tortoise, these urates are secreted normally when urinating. In a dehydrated tortoise that is recycling its urine, the urates are not secreted, and can slowly build up into a bladder stone.

The exact cause is unknown. Dehydration plays a significant factor in this disease. Many people believe that tortoises get all the water they need from their food. This is not true, they need to drink water also, so make sure fresh water is available all day.  

Periodic soaking is recommended. Use lukewarm water, make sure the water level is no higher than the beginning of the top shell (carapace), and soak for up to 10 minutes.

Dry your tortoise off before placing back in its normal environment. Do not soak if your tortoise has surgery unless recommended by your veterinarian.

Diet is also a factor in this disease. For all tortoises, the overwhelming majority of their diet is from plants. If the diet is too high in protein, which would be from feeding dog or cat food, there might be excess urate production, leading to an increased chance of a bladder stone being formed. Your tortoise’s diet should consist of a high percentage of grass, and a lesser amount of green, leafy vegetables.

Here is an older video showing pooping behavior…


There are no specific symptoms that tell us a tortoise has a bladder stone, and some of them don’t show any symptoms at all. The more common symptoms are nasal discharge, poor appetite, straining to have a bowel movement, inability to lay eggs, lameness in the back legs, and lethargy.

A tortoise can become paralyzed in the back legs due to mechanical pressure from the bladder stone. The problem can even progress further, and some tortoises can succumb to the bladder stone.

Of the four major macromolecules in biological systems, both proteins and nucleic acids contain nitrogen. During the catabolism, or breakdown, of nitrogen-containing macromolecules, carbon, hydrogen, and oxygen are extracted and stored in the form of carbohydrates and fats.

Excess nitrogen is excreted from the body. Nitrogenous wastes tend to form toxic ammonia, which raises the pH of body fluids.

The formation of ammonia itself requires energy in the form of ATP and large quantities of water to dilute it out of a biological system.

Birds, reptiles, and most terrestrial arthropods, such as insects, are called uricotelic organisms because they convert toxic ammonia to uric acid or the closely-related compound guanine (guano), rather than urea.

In contrast, mammals (including humans) produce urea from ammonia; however, they also form some uric acid during the breakdown of nucleic acids. In this case, uric acid is excreted in the urine instead of in feces, as is done in birds and reptiles.

Of the four major macromolecules in biological systems, both proteins and nucleic acids contain nitrogen. During the catabolism, or breakdown, of nitrogen-containing macromolecules, carbon, hydrogen, and oxygen are extracted and stored in the form of carbohydrates and fats. Excess nitrogen is excreted from the body.

Nitrogenous wastes tend to form toxic ammonia, which raises the pH of body fluids. The formation of ammonia itself requires energy in the form of ATP and large quantities of water to dilute it out of a biological system.

Let us know your ideas and comments below!