Im observing my male Boa laying next to the water dish with his head partially submerged in the water. Back up 15 min. He was drinking and the decided to submerged his entire head and leave it submerged for a minute or lifted it up and repeat. Additionally he opens his mouth randomly like he is yawning and sometimes only slightly. I hear him make a low hissing noise but if i put his head near my ear I do not hear any real stressed breathing.