Overview of the feline kidneys, ureters, bladder, and urethra, and how the cat's desert-ancestor physiology produces highly concentrated urine.
General educational reference only — not clinical or veterinary advice. Anatomy varies between individual animals; consult a licensed veterinarian for any health concern.
Kidneys
Cats have two kidneys that filter waste from the blood and regulate water and electrolyte balance. As descendants of desert-dwelling ancestors, cats are efficient at conserving water and naturally produce relatively concentrated urine. The kidneys also help control blood pressure and red-blood-cell production.
Urine pathway
Urine drains from the kidneys through the ureters into the muscular bladder, where it is stored. It then leaves the body through the urethra. The male feline urethra is notably long and narrow compared with the female's.
Water conservation
By reabsorbing water efficiently, the feline kidney can produce very concentrated urine. This reflects an evolutionary adaptation to obtaining much of their water from prey. Water intake, diet, and ambient conditions all influence urine concentration.
Sources
Veterinary anatomy and physiology texts; Merck Veterinary Manual (general reference)
