And that's just his Jakarta home life. On top of that is his day-to-day work, spending days on end in some of the world's most impenetrable rainforests, which harbour flying snakes, drug-resistant strains of malaria and several potentially hostile tribes who only gave up headhunting a few years ago - all in the name of the orangutan or "man of the woods", one of the world's most endangered animals.
Dr Smits - botanist, biologist and speaker of 13 languages - is the director of the Wanariset Orangutan Rehabilitation Centre in East Kalimantan in Indonesian Borneo and also an adviser to the Indonesian Minister of Forestry.
He is the orangutan's last hope in this part of Borneo as their numbers decline still further. More each year are being captured for the illegal pet trade - some by corrupt officials - or slaughtered for food by villagers as they flee forest fires. Sunday morning at dawn, the only cool part of the equatorial day, finds Dr Smits doing his rounds of the cages at the Wanariset centre.
"Some baby orangutans have woken up even though they could not have heard me approaching," he said. "They must have smelled me or felt my presence."
The centre was filled to capacity with 171 orangutans, and there was still more than a month until the next lot were big and healthy enough to be released back into the wild.
By 8am he was on the road with his team, two forestry policemen and a week's worth of equipment - everything from microscopes to maps and cages to confiscation papers. He is heading for the remote interior, first along rough rainforest roads and thereafter by speed boat.
In the village of Muara Bengkuang the team found an orangutan barely alive in a cramped cage and coated in layers of its own excrement. Willie confiscated the animal and chastised the Dayak tribesman responsible.
"He was no trader, but to keep such a gentle animal for two years in such a dark, dirty place is mean, and I cannot help but feel uneasy that he will get away with just a confiscation charge," he said. "On the other hand their culture is so different - to them orangutans are food."
Dr Smits sleeps less than Margaret Thatcher's fabled four hours a night. He woke before dawn again on Monday, although this time in a logging camp deep in the rainforest, and he immediately embarked on more confiscation raids in nearby villages.
"It's always the same story," he said. "The fires destroy the organutans' habitat so they come into villages looking for food. The villagers are also hungry, so they kill the adult orangs for food and keep the babies as pets. But what is the point of having a pet that you don't look after?
"I'm afraid this is the tip of the iceberg. For every baby we find, there are two or three we don't; and for every baby, a mother has almost certainly been killed. Start adding it up and you can see why this is a disaster. I am pessimistic for the future of the orangutan in East Kalimantan."
Tuesday was evacuation day for the injured orangutans. A helicopter swept in low over the tree tops to airlift the little ones back to Wanariset for urgent medical treatment. Then Dr Smits and his team were off again, heading deeper into the rainforest on the scent of a key orangutan trader. His scouts had turned up useful leads.
At lunchtime the next day Dr Smits moved in for the kill, but the man he caught by pretending to be an interested orangutan buyer turned out to be only a small trader, not the big one we were after. He was disappointed, but at least now had some bargaining power. The small trader faced a prison term which could only be reduced in return for informing on the big trader.
It is rare for Dr Smits - a Dutchman who has lived here for 19 years - to be in unfamiliar territory, but Thursday found him heading up a tributary of the "Cut-Off-Head" river to Benhes, the last Dayak village before the wild uninhabited interior. From the air some weeks before Dr Smits had spotted its great forest, and knew at once it was perfect for releasing orangutans. The Dayaks were happy to protect orangutans as best they can for they believe they were once human beings. Now all he has to do is persuade the Indonesian government it is a good idea.
On Friday he was back at Wanariset for a sensitive operation to remove a spearhead from a female orangutan's groin. She made it.
Saturday was a rare day off and he flew to Jakarta to see his family, living virtually in hiding since the firebomb attack, for fear of reprisal attacks.Reuse content