Seduku is not happy. Relentlessly, she hammers at the coconut shell, smashing it onto the wooden deck. Despite her best effort s, she can’t seem to crack the thick, coir-covered husk open. She’s no amateur, though: the oldest of all the orangutans at Semenggoh Nature Reserve, this 45-year-old grandmother is not one to give up easily. Indeed, like all the red apes at this 1,600-acre nature reserve, near Kuching, the capital of the Malaysian state of Sarawak, Seduku has already overcome considerable adversity to be here. Down it comes again, and wham: the glossy white milk comes spilling out.

A total of 27 semi-wild orangutans reside in the primary forest surrounding Semenggoh, although its focus has shifted somewhat since opening in 1975. Having successfully released so many red apes into the reserve over the last 40 years, the rehabilitation programme has now transferred to Matang Wildlife Centre in the Kubah National Park, allowing Semenggoh to concentrate solely on studying the biology and behaviour of its tree-dwelling residents. However, a key part of the centre’s activities also revolves around raising awareness about the plight of the beleaguered primates, which it does through twice-daily feeding sessions.

Open to the public, these provide supplementary rather than essential sustenance for the apes, which are otherwise encouraged to forage in the forest for themselves. Yet it’s the relative scarcity of food in the jungle, combined with their solitary existence and slow reproductive cycle — which can see a span of up to eight years between offspring — that explains why orangutans are in such a predicament. The other reason, of course, is man — responsible for the illegal pet trade, palm-oil plantations, habitat loss and hunting for meat or medicine. According to the WWF, worldwide numbers now stand at around 75,000, confined to Borneo and Sumatra, where once they roamed as far afield as South China and mainland Indonesia. But centres such as Semenggoh are seeking to redress that balance, giving orphaned or captured orangutans a sanctuary in which to roam.

After watching Seduku do her worst with the coconut husk, as two of her six children and grandchildren play contentedly nearby, I move through the jungle to the main feeding stat ion. The sound of the rainforest intensifies as I walk, hinting at the gibbons, porcupines, crocodiles, river terrapins and birds that also call Semenggoh home. Cicadas and frogs chime in as I reach a clearing and wait for the afternoon’s fruit delivery to arrive. Semenggoh tries to keep things as natural as possible. A few overhead ropes and the feeding platforms are all that suggests the presence of man.

Then, suddenly, the ropes begins to move. With perfect dexterity, a flash of red hairzip-wires down the line, scooping up bananas with her hands and feet. This, I discover, is Analisa, a 19-year-old female, who swiftly retreats to gorge on her pickings. Like Seduku, she’s a regular at feeding times, more reliant perhaps on the supplementary food than the males. This becomes especially pronounced during the ‘fruiting season’, roughly from November to February, when wild food becomes abundant and sightings of the apes, females or males, can be rare.

It’s time to draw the session to a close, we’re told by warden Dominic, who jokes the orangutans need to find a hotel room for the night. But Seduku is refusing to bid us farewell. As her son Ganya and her grandchild Anaku gambol in the branches above, she stretches out on her back, red-tufted belly turned up ward, and lets her hands thud heavily onto the deck. She may be in her twilight years, but I’m pleased to see she’s not growing old gracefully. Feeding at Semenggoh take place twice daily, from 9-10am and 3-3.30pm.