Beaked whales in general are fascinating. Only a fraction of a percent of people will likely every see one and only a fraction of those people will even know that they're seeing something more notable than any other whale. They're incredibly poorly understood to the point where there are very possibly species that are completely unknown to science.
I was amazed at that as well about the Elephant Seal.
"One final note about life in the abyss: not all intruders from the lighted world are ROVs
or submarines. A southern elephant seal tagged by Census project TOPP recently dove
down 2,388 meters (~1.5 miles) from the surface. At that depth, water pressure is
roughly equal to 240 times the air pressure at sea level. The human eardrum can rupture
at 10 meters"
https://en.wikipedia.org/wiki/Beaked_whale