Old record penned by Animals leads to more yawning (6)
I believe the answer is:
deeper
'more yawning' is the definition.
Both the definition and answer are comparative adjectives. Perhaps there's an association between them I don't understand?
'old record penned by animals' is the wordplay.
'old record' becomes 'ep'.
'penned by' indicates putting letters inside.
'animals' becomes 'deer'.
'ep' put into 'deer' is 'DEEPER'.
'leads to' acts as a link.
Can you help me to learn more?
(Other definitions for deeper that I've seen before include "more involved" , "Wiser" , "Lower in pitch" , "More profound or more intense" , "Profounder" .)