Naked Bike Ride spokesman Conrad Schmidt said six squad cars and a paddy wagon showed up as the group of about 75 naked cyclists arrived along the city's English Bay.
They were taking part in a naked bike ride event, which happens several times a year. Such protests are taken periodically as part of the World Naked Bike Ride
It is an international clothing-optional bike ride in which participants plan, meet and ride together en masse
on human-powered transport (the vast majority on bicycles, and fewer on skateboards, rollerblades, roller skates) to "protest oil dependency and celebrate the power and individuality of our bodies."
Conrad Schmidt said the boy was in tears as police took him and his father away.
He said the arrest prompted the group to cycle through downtown Vancouver to the police station.
Vancouver Police Const. Jana McGuinness said several people had called police, concerned about the child's well-being. Police arrived and reached an agreement with the man that both he and his child would wear underwear during the ride.
As he left to join the group on the ride, the man stripped his and his son's clothes off. The father was then arrested at the scene of the bike ride under public nudity laws.
However, McGuinness said it appeared the man regretted his actions.
"When they were leaving (the scene) it was under the understanding that perhaps he hadn't shown the best judgement, there were a number of people that took offence to the child being naked in the group and subjected to people's scrutiny," she said. "It sounds like it's been a good lesson all around."
Some apparently stayed away from the police station protest to express their unhappiness over the way the father dragged his son into the protest ride.
One cyclist who declined to give her name said the man took off the boy's pants
"The leaders of this event do not support what the guy did," she said.
"I think that's wrong. The kid's a minor."