In addition to this, studies have shown that the third eye can help a bearded dragon navigate based on the position of the sun.
Parietal eye testing was performed on Italian wall lizards at Italy’s University of Ferrara. Researchers surrounded a pool with fencing and trained the lizards to swim across the pool onto a small ledge. There was nothing blocking the sky, so the lizards could use the sun as a point of reference.
Once the lizards were able to successfully swim across the pool, scientists moved them into closed rooms for a week so that they could control the light cycle. Some rooms had lighting that matched the natural day and night cycle going on outside. The other rooms used erratic lighting to throw off the lizard’s internal clocks.
The researchers performed swimming tests on the lizards again and only the lizards that were in the first rooms were able to successfully swim to the ledge. The other lizards appeared to be confused by the differences in where their internal clocks expected the sun to be and where it actually was.
This result was further confirmed when scientists covered the parietal eyes of the lizards and ran the swim test again. The lizards appeared to lose their sense of direction and ended up swimming randomly around the pool.