What actually goes through the mysterious hole in its skull is a large blood vessel ... vessels is expected to be present under the skin of all snakes, what is special about H.

Let's start with that skull: The bones are connected by ... lower jaw to widen to make room for its meal. The skin stretches. How does the snake breathe while its mouth and throat are full?

"We found that both habitat use and diet preferences are strongly correlated to skull shape in this group of snakes, indicating these are likely factors driving cranial evolution for these species." ...