The water in the teapot at the centre of the circle is for washing our hands, but it will be the first thing guzzled, should the fish heads prove difficult to chew.

Remembering not to accept food if it is offered in jest with the left hand (it’s the hand they use to wipe) I roll a ball of steamed rice and boiled jungle fern in the palm of my hand.

It’s on standby as a chaser if the water doesn’t stand up to the task.

Fortunately, our concerns are allayed when our host, Jeff, suggests we move from eating our meal on the floor to playing a game of cards. No complaints there.

It’s our first taste of life in the small village of Batu Puteh, on the banks of the Kinabatangan River, in Malaysia’s north-east state of Sabah.

On the bus ride from the region’s capital, Kota Kinabalu, most expect vast stretches of pristine rainforest, but much of the five-hour trip is spent looking out across palm oil plantations.

It was here during the ’80s and ’90s that rainforests were flattened at a phenomenal rate for their timber, and now less than half of what once stood remains.

For most of the men from Batu Puteh and other villages in Sabah, the plantations are a main source of employment, creating a juggling act for the government when pressured to protect what’s left of the forests.

Despite widespread deforestation, this northernmost region of Borneo is one of the world’s richest ecosystems, and still lures countless visitors keen to catch a glimpse of sun bears, hornbills, proboscis monkeys and the star attraction: orang-utans, whose name means literally ‘man of the forest’.

A trip up the river at dusk affords the best chance of seeing the wildlife.

We’re here in the wet season and the regular afternoon storm brewing on the horizon sets a moody backdrop for the wide murky river and its lush tree-fringed banks, as our traditional kelotok boat motors through a light sun shower.

Jeff scours the trees for any movement, and before long we slow to a halt to catch a string of strange-looking proboscis monkeys leaping between tree branches, some with their young clinging to their undersides.

A passing kelotok quickly creates a buzz in the group with word of an orang-utan feeding a few hundred metres around the bend.

Unfortunately, the typically shy ape cottoned on to the frenzy and made itself scarce before we could reach it.

It’s one of about 20,000 wild orang-utans on Borneo, and while this animal proved elusive, Jeff assures us we won’t be disappointed tomorrow when we reach Sepilok.

After a night spent dodging leeches, plastering ourselves in mosquito repellent and sleeping in a hammock, we relish the chance to freshen up with buckets of cold water at our host family’s home.

Jeff’s timber house is basic but spacious, with nine family members living under one roof.

I lose track as he reels off names every time someone new files through the door.

There’s an influx when four relatives return from a nearby mosque.

While Malaysia is an Islamic country, not all Muslims here are practising.

We’re told that Muslims don’t drink alcohol, but in the same breath we hear about the spirits some of the men enjoy.

The next call to prayer resonates at 5.30am, leaving a light sleeper little option but to rise early ahead of a journey to the Sepilok Orangutan Rehabilitation Centre. Operating since 1964, the reserve is home to between 60 and 80 orphaned or confiscated orang-utans.

A further 25 young orphans are being rehabilitated in the centre’s nurseries, learning ‘pre-school’ skills such as foraging, nest building and climbing.

These are some of the lucky ones, as an estimated 250 to 1000 wild orang-utans are still captured and sold on the black market each year.

As we make our way along the boardwalk towards the viewing gallery, a couple of young orang-utans cartwheel their way along the ropes to reach the feeding platform.

The keepers only feed the apes a monotonous menu of milk and bananas so that the young animals learn to forage for their own food.

It’s easy to see that orang-utans share 97 per cent of their DNA with humans, when their behaviour closely resembles that of children.

On the platform, a younger ape’s hyperactive antics become too much and a larger adolescent chases him off so he can eat in peace.

While many of their actions mimic those of humans, the right-hand-for-eating rule is never going to hold much weight with an orang-utan.

Their Sepilok menu might seem boring, but at least they won’t face the uncertainty of a plate of leftover fish heads.

» Dan Imhoff travelled to Borneo with Intrepid Travel (020 3147 7777). The 10-day Sabah Discovery tour is £545, plus about £97 for local payment.