They toured a hospital, complete with an accident and emergency department and operating area, and watched as a patient was treated.
In this case, though, the patient was a Gambian rat.
This tour of the animal hospital was one of the highlights for 27 children who got a chance yesterday to see what goes on behind the scenes at the River Safari.
The children, who are beneficiaries of The Straits Times School Pocket Money Fund (STSPMF), were on an educational tour.
They were accompanied by Straits Times journalists and volunteers from Samsung, which sponsored the excursion.
Each child also received a Samsung Galaxy tablet.
Besides the animal hospital, some children visited the Wildlife Nutrition Centre too, also called the Central Kitchen, where animals' meals are prepared. Both places are not usually open to the public.
The children tried their hand at cracking walnuts that keepers give to capuchin monkeys - which open the nuts by smashing rocks on them - and took a whiff of the food pellets that flamingos eat.
They also took part in a scavenger hunt, planned by the ST journalists, that took them through the entire River Safari.
Junyuan Primary School pupil Ashley Yaw, 12, said: "I really liked the behind-the-scenes tour because it's not something that you can usually see when you visit the River Safari.
"We learnt many new things, like how orang utans can actually drink Milo and even tea."
STSPMF, started in 2000 as a community project by ST, provides pocket money to children from low-income families to help them through school.
The children can use the money for school-related expenses, such as buying a meal during recess or paying for transport.
The fund has disbursed $68 million to help more than 170,000 children and young people in need.
STSPMF general manager Tan Bee Heong said: "Our beneficiaries had a fun and memorable time. We are thankful to staff from The Straits Times and Samsung Electronics Singapore for taking time to take the students on this outing and for bringing so much joy to our children from low-income families."
• Additional reporting by Cara Wong