The prison yard is filled with loud grunts and heavy clunks - the unmistakable sound of men pumping iron.
Tattooed inmates bathed in sweat are working out in the outdoor gym behind the razor wire of the Lansing Correctional Facility in Kansas.
Suddenly there is a very different sound - a high-pitched whimper. On the other side of the yard where another group of tough guys have found something else to occupy them - a puppy.
"Hold still, little fellow," laughs a man in a blue shirt as the tiny puppy scampers over his feet and across the grass.
Finally the man, inmate Danny Johnson, succeeds in catching the terrier and cradles him in his arms.
"This is Reno and he is quite a character," he says proudly. "He and his sisters were abandoned so we're looking after them now."
Danny is near the end of a 10-year sentence for aggravated kidnapping and burglary.
Inmate Danny Johnson has found his work caring for dogs therapeutic
He tells me that he was arrested after he broke up with his girlfriend and stormed into her house armed with a rifle. He no longer talks to her or to his children who stopped visiting years ago.
But despite all that, he says he feels positive about the future. He is hoping to set up his own animal shelter after his release.
"Working with the dogs, it helps me to help them. Big time. You know it is such a joy to do that.
"Some of them come in here with serious injuries, they have suffered terrible cruelty. I try to make sure that they recover and I get them to trust people again - it's amazing to see how they change."
The Safe Harbour programme, which gets the inmates to rehabilitate abandoned dogs is well-established and popular with people on both sides of the prison fence.
It has not been without controversy. In 2006, one of the local volunteers helped a convicted killer to escape by hiding him in a dog crate and driving him through the gates.
But Warden David McKune says that after that episode he received several letters and cards in support of the scheme.
"We believe that the benefits outweigh the risks," he says.
Security has been tightened up however and dogs now must be walked into and out of the prison.
In another part of Kansas two hours' drive away, prisoners are breaking in wild horses on a mustang ranch.
The horses come from states such as Wyoming where federal protection and a lack of natural predators have led to overpopulated herds.
The mustang ranch at Hutchinson Prison where inmates tame wild horses
Since vegetation and water could become dangerously scarce if there are too many animals, the US Bureau of Land Management rounds up the excess numbers.
Some of the horses wind up in prisons where they are tamed by inmates. Later they are offered for sale or adoption by the general public.
Sam Cline, the warden of Hutchinson Prison, is keen to show me what a good job his men are doing.
"Animals are unconditional in their affections and they really do give an individual an outlet for his tensions," he says.
"Sometimes we find men who can't relate to authority figures relate much better to the horses."
Don Austin, who says he got into trouble because of drugs and alcohol, is clearly attached to the horses. He strokes one on the nose and pats its glossy neck.
"It is therapeutic for me to take care of something and right now since I can't be with my kids; it helps me out a bunch to have a creature that needs me.
"A creature that is looking forward to me being there for meal times, grooming or whatever."
Fellow inmate Jimmie Barnes agrees and tells me he much prefers working on the ranch than sitting in a prison cell indoors.
Inmate Jimmie Barnes does not see his work on the ranch as a soft option
But what would they say to people who feel that convicted prisoners shouldn't be having fun riding horses?
Jimmie scoffs at the idea that breaking in wild horses is a soft option.
"If you have ever tried to do the ground work in one of these round pens with a wild mustang it is not always as much fun as it is cracked up to be.
"I have seen guys coming out there just dripping with sweat, you know."
I watch as a stallion which has never been touched by a human before is gently coaxed into the pen and made to walk in different directions.
His ears are flattened and he looks furious as he bucks and whinnies but Jimmie never raises his voice and moves with quiet confidence.
Warden Cline says being tough with these animals simply does not work.
"Some guys have a lifetime history of abusing people but if you play that game in the animal kingdom, you are going to pay the price pretty quick.
"We want our men to learn to do things with a patient, controlled, self-disciplined approach that doesn't allow for violence or outbursts of their own emotions.
"Hopefully when they leave prison, these are tools they'll use with other people."
My impressions are that these horses really do help to change these men. But as night falls the ranchers become convicts again when they return to their cells.
With their fluorescent lighting, metallic surfaces and constant noise, prisons seem to amplify, even encourage the occupants' aggression.
A prison in Norway has disposed of those buildings altogether and created the world's first eco-jail on an island in a fjord just south of Oslo.
The men at Bastoey are not petty criminals. Most have committed serious offences including murder and rape and they began their sentences in traditional closed prisons from where they applied to live on the island.
Those who are accepted must be willing to embrace the underlying philosophy here - that respecting nature helps you to respect yourself and other people.
Arne Kvernik Nilsen, the governor of Bastoey, says some prisons make bad people worse and criminals are often more dangerous to the community when they are released from traditional prisons.
Bastoy prison in Norway operates a working farm run by inmates
"I see this as a place of healing", he tells me. "We are trying to repair the damage we have caused by lock people up in old fashioned, high security prisons."
Proper research has yet to be done but the governor says according to certain tests, reoffending figures are much lower than in ordinary Norwegian prisons.
Of course the population here is carefully selected.
But another indication that the prison does work is that in five years there has only been one escape even though the prisoners are the ones who run the ferry service to the mainland.
I meet Jergen, who's serving a sentence for drug trafficking, sitting in the sunshine over a cup of coffee in the port of Horten - 20 minutes across the water from the prison.
He says he enjoys working on the ferry but above all he loves to work on the prison farm with the animals. With a broad smile he talks about learning to deliver calves. "We've had some complicated births - once I had to put arm inside and turn the calf around. Another time a mother died so I had to bottle feed the calves. Every time I see them walking around I feel as if they are my children!"
BBC NEWS | World | How puppy love helps US prisoners