Chief executive of SPCA Ric Odom said he agreed with the jail sentence for Heka.
"Heka's crimes are genuinely disturbing and some of the worst offending we've seen,'' he said.
"Basically, people who abuse animals are also very likely to abuse people, so a custodial sentence is fully justified.''
Mr Odom said the case raised the issue of how New Zealanders treat so-called pests like possums.
"Although possums do significant damage to our forests and it is legal to hunt, trap, and kill them, it is still an offence to ill-treat them,'' he said.
"If you kill them, you must do so humanely and avoid inflicting unnecessary suffering on them. All animals are sentient living things that feel pain and distress.''
Man who nailed possum to tree to serve jail time
