Like many Singaporeans, I have fond memories of going to the Singapore Zoo as a child.

I have also visited several times in recent years and they have always been free-and-easy affairs.

I decided to experience it a little differently this time by engaging a guide from local travel company Xperience Singapore to take my family around the exhibits.

And I can happily say that the Zoo - Declassified! tour has given me a new-found appreciation for our beloved park.

In a tour that lasted more than two hours, I learnt a lot more about the different species and why their exhibits are built a certain way, more than I would have from just reading the signboards.

Our experienced guide could rattle off trivia and answer a barrage of questions, mostly from my seven-year-old daughter.

Children are naturally inquisitive and I am glad there was an expert to save me from having to Google the answers every few minutes.

We took the morning tour, which started at 10am, and headed to the Treetrop Trails to look for Anna and Ako, a pair of tree-swinging siamangs or gibbons.

Our guide talked about the zoo's open concept and free-ranging areas, which allow the animals to roam about in natural surroundings without being confined to cages.

At the free-ranging area for orang utans, it was quite a sight to see the primates manoeuvre the interconnecting vines right above our heads.

My seven-year-old asked what stops the animals from escaping if there are no cages to hold them in.

Our guide explained that the zoo uses several ways to keep animals in - for example, having a moat around animals that cannot swim.

He added that, by giving the animals enough food and water and shelter, they are content to stay and not make a break for it.

The zoo also gives the animals plenty of opportunities to act on their natural instincts.

For example, the cheetahs chase mechanised rabbits as a form of exercise, and meat for the big cats are hidden in gunny sacks for them to tear into.

We learnt that animals such as ostriches and zebras are placed together to create "positive stress" so they will not get bored. And male baboons sometimes "steal" babies from the females just to be fatherly.

I had also wondered about the white rhino. Judging by the dirty brown tone of its hide, I found its name a bit of a stretch.

But, as our guide explained, the name comes from the Afrikaans word "weit", referring to their wide muzzle, which somehow later became "white".

The zoo's Fragile Forest zone, a biodome built as a tropical rainforest habitat, was a hit with the kids. My two daughters could not resist the cute free-roaming animals, from mousedeer and eclectus parrots to two-toed sloths and Malayan flying foxes.

The tour covered about 70 per cent of the zoo. It ended at the Great Rift Valley of Ethiopia exhibit, where my family took a break. We later continued on our own to look for the white tiger and hippos.

The price of the tour ($35 for adults and $30 for children) does not include admission to the zoo (from $31.20 for adults, $20.80 for children and $18 for senior citizens).

But you can use SingapoRediscovers vouchers to offset the costs of the tour and zoo admission.

The Zoo - Declassified! tour is available only on Mondays this month because of the large turnout due to the school holidays. From next month, tours will be moved to the weekends.

The zoo also conducts its own tours, although some have been suspended. For now, only the Private Buggy Tour is available (from $240 for up to five people), but it is fully booked until the end of this month.

• Eating Air is an occasional series on local tours. For more stories on exploring Singapore, go to str.sg/sg-go-where