They are desert animals and their bodies have adapted to extracting most of the water from their food. In the wild, they don't have access to water all the time and the food they eat very often isn't that moist. So producing urine is a waste of water and they have reduced it to a minimum. That's an adaption you will find in many desert animals.
Once a month is fine. Gerbils are desert creatures so produce very little urine and waste compared to other rodents.
To conserve water
a camel produces very little sweat and urine
Gerbils have water-conserving internal systems that use little water, and use that little water, they do not waste water. They excrete very little liquid. They also burrow to stay cool.
You must see your doctor.
Very little sweat and urine is not a structural adaptation. It only means your body is dehydrated and that all the fluid is being absorbed. If it is only no urine, there may be a problem with your urethra. Not urinating is very bad for the body as toxins build up in the body therefore, very little sweat and urine is not a structural adaptation.
It is advantageous for survival to void little liquid in hot conditions. A camel does not store water in its humps. The water that it drinks is absorbed into its bloodstream.
Lime. In fact, don't put chlorine in contact with urine. It can produce very toxic fumes.
my gerbil is called snuffles and she is very clever she is very quiet but if you hold her next to your ear then you can hear her doing very quiet squeaks. if i grab her a bit too hard then she does a louder squeak and you will easily hear her. i hope your gerbils are as clever as my little snuffles. i have trained her tricks:)
Gerbils have evolved special kidneys and some other adaptations to survive with very little, if any, water.
because some camels have very little water, or they preserve water in their humps
because they save water