 Dear students, in this topic we shall discuss asthma regulation in marine mammals. The marine mammals, for example whales, dolphins, sea lions, corpizes and seals, avoid drinking seawater because they have no extra renal salt glands so they cannot excrete excess salt. This is the strategy for not drinking water. When they are living in an environment where they cannot drink water, their environment becomes just like a desert. So they have desert like problems faced by them living in marine water which is without availability of drinkable water. So their physiological responses are generally similar to those of the desert dwelling mammals. However the details of these physiological adaptations vary. Now we shall discuss the asthma regulatory strategies of mammals living in marine environment. Marine mammals have the biggest problem that is the loss of water through excretion and respiration. So their strategy is water conservation. They can obtain water through intake of food and through its subsequent metabolism. So they utilize the metabolic water produced. They also depend on their kidneys for maintaining osmotic balance. Their kidneys are highly efficient which are capable of producing very hypertonic urine that minimizes the loss of water during excretion. Seals have nasal passages which have a labyrinth like proliferation of epithelial surface which reduces respiratory water loss. While whales and dolphins have a blow hole that cools the air passing through it. This is how respiratory water loss is minimized. Many also reduce respiratory water loss by suspending breathing for quite long time. Maybe up to 40 minutes. So when the breath is not taken, water loss will not occur. In females, milk production is one more reason for water loss. Because milk contains about 90% water. But this loss is minimized by producing highly concentrated milk in marine mammals. The milk in marine mammals that is about 10 times more concentrated as compared to a cow's milk.