 Dear students, in this topic, we shall discuss osmoregulation in terrestrial animals. Terrestrial animals face the problems of both water and salt loss. Water and salt loss occurs because they have water permeable epidermis. This loss occurs through respiratory epithelia, by the production of sweat and through urine excretion. To maintain a balance between the loss and gain of water and salt, the terrestrial animals feed on moist and salty food materials, which compensate for the deficiency of both water and salt. Additionally, for water regulation, either they drink water, or they adopt water conserving strategies by physiological and behavioral means. Terrestrial animals have a lot of physiological adaptations to reduce their osmotic problems. The first of them is the water-proof covering of the body, which prevents evaporation of water. These coverings include porno scales, which are developed by reptiles, feathers, which are developed by birds, and fur, which are developed by mammals. In addition, terrestrial arthropods have a chitin-exoskeleton, which also prevents evaporation of water loss. In addition, various mechanisms check the loss of water through urine and feces. These two processes are a major cause of water loss. Rectum and Kalwaika absorb water from feces. Whereas water from urine is reabsorbed by the loop of Henle in kidneys. In addition, arthropods, birds, snakes, or lizards convert these water conserving strategies into uric acid during evolution. So that uric acid is excreted in a semi-solid form and uses minimum water for its excretion. In addition to these strategies, the animals that live in a very hot and dry desert environment adopt more water conserving strategies than these animals.