Why do spinosaur skull grooves hint at salt glands?

Answer: To excrete excess salt

To excrete excess salt ✓ — Correct! The grooves on spinosaur skulls match the pattern of salt-gland ducts in modern reptiles like seabirds and turtles. These glands filter excess salt from the blood and expel it through the nostrils, helping animals that drink seawater or eat salty prey. This suggests spinosaurs faced similar salt stress, possibly from a brackish or marine diet.

To store water — Wrong. Water storage organs, like a camel's hump, are not associated with skull grooves. Salt glands are about removing salt, not storing water. The groove pattern is specific to duct systems, not reservoirs.

To anchor jaw muscles — Wrong. Jaw muscle attachments leave different marks—rougher areas for tendons, not smooth grooves. The grooves are too fine and positioned differently from muscle anchors. They are more consistent with soft tissue ducts.