John, who is a listener of the show writes “In episode #218 one of the guests mentioned he saw the animal produce the wood knocking sound by rapping it’s knuckles against a tree.
The surprisingly heavy wood knocking sound produced by the fist is likely indicative of unusually high bone density combined with the force a large massive creature can produce.
I once had a 220lb martial art instructor who would casually rap his knuckles on the walls as he walked down the cinder block hallway to class. When he did this it sounded like someone hitting the wall with a sledgehammer. At first we didn’t know what he was doing to produce the sound. When asked, he showed us but no one could reproduce it. When the average person did it, the sound was very quiet and weak, more like a feint tapping, additionally it hurt too much for someone with untrained bones to hit hard enough to be any louder. If you shook the instructor’s hand it felt waaaay heavier than it “should”. His bone density was significantly higher from decades of hitting bricks and heavy objects.
I witnessed this many times after with other highly skilled martial artists who were capable of breaking marble slabs with their bare hands with zero sign of injury. Upon shaking their hands I never ceased to be amazed by the weight of their hands.
Check out “Wolff’s Law”
“Wolff’s law is a theory developed by the German anatomist and surgeon Julius Wolff (1836–1902) in the 19th century that states that bone in a healthy person or animal will adapt to the loads under which it is placed.”