By Orla Guerin
BBC News Africa correspondent
Many Zimbabweans feel driven to flee by poverty and hunger
How far would you go to put food on the table?
Would you take your life in your hands - wading through crocodile-infested waters, and walking unprotected through land where leopards roam?
That is what Monica has just done, for the sake of her three-year-old daughter.
She has joined the exodus of Zimbabweans crossing illegally into South Africa - the so called "border jumpers".
They travel in the dead of night, guided by traffickers. The going rate is 200 rand (£14 or $28).
We met Monica shortly after dawn, as she emerged from the bush about 6km (3.7 miles) inside South Africa.
She was on foot with four other women - their faces showing the strain.
Monica told us they had been travelling for four days with traffickers who abandoned them when their money ran out.
"They called us baboons," she said. "They told us if you have no money we will leave you here and call the police to come and arrest you.
"We have nowhere to go right now. We have no money and the police are all over. We don't know what to do."
Monica was driven out of her homeland by poverty, hunger, and concern for her little girl.
"The situation is very bad," she said. "We will try by all means to get jobs. We can't go back. We are starving in Zimbabwe."
Mary, one of her travelling companions, is a mother of four. She also talked of starvation.
"We've got no jobs," she said. "We can't do anything in Zimbabwe. We are suffering."
After resting for a few moments the women picked up the few belongings they were carrying, and began walking towards the highway.
With no money and no place to go, their ordeal may be just beginning.
A short distance away a group of taxi drivers were waiting at a favourite rendezvous point - under a baobab tree.
They are part of a highly organised and lucrative trafficking network.
The taxi drivers have spotters with mobile phones, who warn if the police or army are near.
A ride to Johannesburg costs a fortune for a Zimbabwean - 1300 rand (£92 or $184).
No-one knows for sure how many border jumpers arrive every day, but the estimate from the taxi drivers is more than a thousand.
Most deported Zimbabweans cross the border again into South Africa
"Even pregnant women or women with a baby on their backs are jumping a 2m high razor-wire fence," one driver said. "Some are carrying newborns. It's bad."
The taxis leave with their human cargo within three to five minutes.
"We phone the guy at the corner," he says. "If he says the place is safe, we take everyone. If not, we offload them quickly."
For some the journey involves jumping fences, or cutting holes in them to crawl underneath. But there are easier places to cross the border, if you know where to look.
We found an area protected by only a single fence. There is no need to cut a hole, because there is an unlocked gate.
Once through the gate, the Limpopo River is just ahead, and beyond it, Zimbabwe.
The Limpopo is low now, but border jumpers have drowned when the river is in flood.
Just downriver another group was making their crossing, holding their valuables above their heads.
Border jumpers must cross a crocodile-infested river
They arrived safely on dry land, but there was a reception committee of local thugs.
They often lie in wait to rob or rape the new arrivals, sometimes tipped off by the traffickers.
The border jumpers spotted them in the distance. There was panic as they rushed to squeeze back through the fence, and return to the river.
They got away this time, but the thieves are a constant threat.
Zimbabwe is haemorrhaging some of its brightest and best.
In Johannesburg these days you find doctors, lawyers and head masters from Harare ready to work as cleaners.
Plenty of illegal migrants are arrested and sent home. So far this year, 57,600 have been deported to Zimbabwe, according to the International Organisation for Migration.
But many attempt the crossing again and again, unable to survive in a country with 80% unemployment and the world's highest inflation rate - now 2,200%.
The price of corn, the staple food in Zimbabwe, has just risen by a staggering 680%. That may drive many more desperate men and women into the arms of the traffickers.
Along the border between Zimbabwe and South Africa, a tragedy is unfolding - though its victims usually pass unseen.
They are women like Monica and Mary - mothers risking everything for a chance to feed their children.