He may be a runt with two broken legs, but Piwi the kiwi is as tough as they come.
RUN KIWI RUN: Piwi stretches his legs on a treadmill at Massey University. The stubborn brown kiwi has been undergoing rehabilitation after breaking both his legs in two separate incidents.
The accident-prone brown kiwi works out regularly on the treadmill in Massey University's Wildlife Ward.
He was first admitted in December after being discovered near Mt Ruapehu with a broken leg that had healed badly.
Piwi would have little chance surviving in the wild, especially as he's only half the size of a normal four-year-old kiwi.
Massey veterinarians had to rebreak his leg to straighten it.
In April he was sent to the Rainbow Springs Kiwi Wildlife Park near Rotorua for further rehabilitation, but broke his other leg the first night he was there.
Losing blood, Piwi was rushed back to Massey University's veterinarian centre.
Fortunately another kiwi was able to provide blood for a transfusion and Piwi pulled through.
But the fight wasn't over.
Palmerston North physiotherapist Fiona O'Connor prescribed a strict rehabilitation regime, including treadmill workouts, massage and physio exercises.
It's the first time veterinarians have used a treadmill for a kiwi's muscle development.
Piwi didn't take to it naturally and would be grumpy when woken for his workout three times a week, Dr Argilla said.
"He was particularly stubborn in true kiwi form, and just sat there [as if saying] I'm not going to do this."
He'd bite carer's hands when he got fed up with walking. But he's quite a tolerant little guy."
Staff from Rainbow Springs picked Piwi up yesterday for further rehabilitation before he is released back into the wild.
It is unknown how Piwi broke both legs, but vets suspect weakened muscles caused the second break.
The wildlife team will miss their favourite kiwi.
Dr Argilla said they had done the best they could for him.
"We are very worried about him, he's so little. Hopefully he finds a mate who will hang out with him."
Watch also a video about Piwi.
People are waiting to help.