Four indigenous children who survived 40 days in the Colombian Amazon after a plane crash have been released from the hospital, authorities said on Friday.

After a monthlong treatment, the siblings were doing "very well," the director of the country's Family Welfare Institute told journalists.

"They are actually very well," director Astrid Caceres said, adding the children had all gained weight.

Lesly, 13, Soleiny, 9, Tien Noriel, 5,  and Cristin, 1, were the only survivors after the small plane they were passengers in crashed in the jungle. 

Their mother and two other adults died in the incident. 

Understanding of the forests helped the kids survive

The four children who were rescued currently showed no physical effects from the 40 days they spent in the Amazon, Caceres said.

She added, even little Cristin is "completely recovered in terms of physical development."

Officials and relatives praised the Indigenous children's knowledge of the jungle and Lesly's courage for their survival in the jungle with its many inherent dangers — including snakes, predatory animals and armed criminal groups. 

It took around 200 military and Indigenous rescuers with search and rescue dogs to track them down. They were rescued on June 9 and taken to a military hospital in Bogota for treatment. 

The Family Welfare Institute will temporarily take custody of the children because of a "complex family situation" that has seen a custody dispute between the two younger children's father and their maternal grandparents.

ara/sms (AFP, Reuters)