These feet come from a Saimang gibbon, the largest species of Gibbon.

They live in the rain forests of Malaysia.
Siamangs’feet have five toes like we have, but the one of the things that sets the Siamang apart physically from the other species of gibbons/Apes is webbing between their second and third toes.
If you look you can see the join!

And of course this would be a far better pik if he's feet were round a branch!