In the late 1970s, Professor Peter Ng Kee Lin was a teenager who needed help with a school project on fiddler crabs and so he went to Professor Leo Tan Wee Hin, an eminent marine biologist at the then University of Singapore.
Fast-forward nearly 40 years and Prof Tan is still helping Prof Ng with crabby tasks. On a recent trip to Borneo, he spent three days combing the jungle for a rare purple crab Prof Ng believed could be found there. In the end, he found an even rarer specimen, which he "smuggled" back to Singapore between two ice-cold cans of CocaCola to preserve the tissues.
Asked why he goes to such lengths for his protege, Prof Tan only smiles. "I spotted Peter when he was in junior college. That kind of student, you don't let go," he says. "I took him under my wing when he was 18 years old. There was this outer insolence - but I like a challenge."
Words to be expected from a person who took up marine biology in part because he nearly drowned learning to swim off Changi Beach when he was a child.
"We had no swimming pools in those days," explains Prof Tan, who turns 71 this year. "I became a marine biologist to conquer my fear of water."
The son of a clerk and a housewife, science was not on the family radar, yet he became the first person to do a doctorate in marine biology from the University of Singapore.
His initial area of interest was molluscs, but he became fascinated with crabs while doing his postgraduate studies at Duke University in North Carolina, United States.
When Prof Ng, then a teenager, approached him for help, Prof Tan was a senior lecturer with many demands on his time, but he felt - and continues to feel - that his first duty as a teacher is "to inspire those with an aptitude for science".
He also saw a kindred spirit in the younger man who was fascinated by the natural world, especially the relatively little-documented aquatic fauna of South-east Asia. To this day, when Prof Tan travels, he has a litre of absolute alcohol in his luggage for preserving specimens and refuses maid service in hotel rooms because the sinks in his room are plugged up and made into makeshift preservation tanks.
So when the similarly collectingcrazy Prof Ng entered university as an undergraduate, Prof Tan offered him laboratory space to do research on lobsters, even though this was frowned upon in those days. Undergraduates were meant to absorb and study, while postgraduates did research.
"I told him there was a lot of money in aquaculture to interest him," he recalls, laughing. "He was very clumsy. He broke every piece of glassware in the lab."
Their connection remained even as Prof Tan was seconded to the Singapore Science Centre as its director in 1982, an appointment he took up full time four years later and held until 1991. After that, he became foundation dean of the School of Science at the National Institute of Education (NIE) and was NIE's director from 1994 until 2008. He was also chairman of the National Parks Board from 1998 to 2007.
In 2008, he returned to the National University of Singapore as professor and director of special projects at the Faculty of Science, and began working with Prof Ng at the Raffles Museum of Biodiversity Research.
Married with two grown sons, he is looking forward to the time when he can take his two grandchildren, now under the age of three, to the Lee Kong Chian Natural History Museum and watch them learn about the natural world he loves so much.
But ask what his enduring legacy is and he does not mention the museum, but its head.
He says: "I've got immortality through Peter. You have to groom the next generation, that's your duty. You reach a certain stage in life when time is not on your side, but if you get successors, the legacy continues."