Knocking on the Gruffalo

We found the Graffalo at Whinlatter. I started knocking on the wood, first on the arm and then on the jaw. I got two distinct notes. The arm was higher than the jaw. I tried to estimate how much by do-re-mi.

I don't have perfect pitch so I couldn't tell you the note but was trying to get the relative jump. I found this: https://thatsmaths.com/2014/08/28/temperamental-tuning/ which doesn't quite agree with https://prgomez.com/why-do-re-mi/ but implies that the frequency of the arm is roughly 1.25x higher than the jaw.