Why do marine iguanas sneeze out white salt after eating algae in seawater?
Show answer & explanation
Answer: Salt glands near the nostrils release excess salt taken in with seawater.
The spray warns nearby iguanas of a predator approaching. — This salt spray removes excess salt rather than serving as an established predator alarm. It helps maintain the animal's internal salt balance. Other iguanas noticing the spray would not by itself make it a warning signal.
The sneeze clears seawater from the airways after feeding in the sea. — The salty secretion comes from nasal glands, not from seawater trapped in the lungs. It removes salt absorbed into the body during feeding. Clearing the airways is a different task from regulating salt in the blood.
Salt glands near the nostrils release excess salt taken in with seawater. ✓ — Marine iguanas expel excess salt through nasal glands after taking in salt with marine food and water. The glands concentrate salt from the blood into brine that is expelled through the nostrils. Salt can dry into white crystals around the snout.
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