SINGAPORE - He is 16 and is already a veteran of guided tours at biodiversity haven Chek Jawa on Pulau Ubin.
Dunman High School student Choo Yi Feng started conducting solo tours for groups of about 15 when he was 12, after a year of training from other guides.
But what made someone so young so passionate about the environment?
Yi Feng said it started after a trip to Underwater World in Sentosa, when he was three.
"I started reading books and watching documentaries about sea animals," he said.
At the age of eight, he visited Chek Jawa, and he knew then he wanted to be a guide.
Despite being told he was too young, Yi Feng continued to learn as much as he could about Chek Jawa's wildlife. On his next visit there, he volunteered as a guide again. He was only 11 then.
The answer from the lead volunteer guide was "yes".
He might know a lot about the wildlife, but it wasn't all smooth sailing for Yi Feng, especially on his first time leading a tour.
"Back in 2009 when I first started, I was so nervous that I missed out several spots on the boardwalk," said Yi Feng.