Crushing my body tightly against a boulder, I'm frightened to even breathe.

Behind this haphazardly stacked kopje sits 50 million years of natural history embodied in almost two thundering tonnes of flesh - the size and power of a BMW car with a notoriously volatile grump at the wheel.

Being within arm's reach - and trampling distance - of one of the world's oldest and most critically endangered species is humbling.

And when heavily pregnant Nadungu detects my presence with her acutely-tuned antennae-like ears, bolting away in a cloud of ochre dust, I'm soberly reminded of how fragile a black rhino's existence has become.

Home to just under 1,000, Kenya is one of the eastern black rhino's biggest strongholds, and efforts are underway to preserve and grow that population.

What's more, tourists are now able to observe the animals at a much closer range than ever before, thanks to a pioneering project to return black rhino to a rugged, tribal territory in northern Kenya - uniquely driven by requests from indigenous people living there.

Launched at the beginning of 2017, Walking With Rhinos is the first black rhino tracking experience in East Africa and the first community owned and managed project of its kind on the continent.

By the mid-1990s, black rhino had been wiped out completely from this remote sector of Samburu County, which now forms the Sera Conservancy. But in 2015, with the help of Northern Rangelands Trust, Kenya Wildlife Service and conservationist Ian Craig, black rhino from the nearby Lewa Conservancy and other national parks in the country were translocated to a fenced 41sq mile sanctuary within Sera. The birth of Nadungu's calf a few days ago raises the current number of residents to 12.

Owned by Italian writer and safari guide Riccardo Orizio, the Saruni stable was exclusively invited to set up a lodge within Sera, six miles from the Sanctuary.

I'd arrived in the neighbouring Kalama Conservancy via a 50-minute bush flight from Nairobi, for an overnight stay at Saruni Samburu, a six-villa hilltop camp drowning in views of enormous skies and burning red plateaus, crowned by Mount Kenya on a clear day.

Driving initially along tarmac road, we soon turned off into the bush for a 45km journey to Saruni Rhino. Villages were a collection of mud and animal hide huts clustered together, and the local 'school' constituted a gathering of wide-eyed children sheltering below the shady, protective arms of an acacia tree. By the time we reached our final destination, the modern world had disappeared almost completely.

Saruni Rhino is remote - even by Northern Kenyan standards - and wonderfully so.

Rhino within the Sanctuary have been fitted with microchips in their horns, allowing rangers to monitor movements and track their whereabouts.

A fleeting glimpse of Nadungu has whet my appetite for further encounters, and on our second outing into the Sanctuary, we go in search of another female, Napanu.

Standing on top of a rocky mound, rangers Thomas and Anthony take turns in holding aloft an aerial, hoping to detect clicks from chip 16; each rhino is numbered and has its own frequency.

Once Napanu has been located, we travel by foot, led by our guide Sambara. Weaving through fairy-tale turrets of termite mounds and spiky commiphora bushes, I painstakingly watch every step, tip-toeing through a minefield of brittle twigs and jagged quartz rocks, trying not to make a noise.

While closing in on our quarry, we reach a stand-off, frozen for 45 minutes as she grows suspicious of our presence. When she finally moves into the valley, we position ourselves at the base of a hill and marvel as she trots slowly towards us, every fold, crease and skin rumple visible in glorious, magnified detail.

This time, there's no rock to hide behind and with only metres of air between us, her breath almost touches my neck. One camera click results in a mock charge, causing Sambara to intervene by shouting and clapping, leaving me drunkenly dumbstruck as one of the world's few surviving black rhinos hurriedly scrambles away.

The return of black rhino to this region of Kenya is more than a conservation effort and revenue generator - it's also a source of pride for the Samburu people. The same is true for the Reteti Elephant Sanctuary, another pioneering community owned and managed project in neighbouring Namunyak Conservancy, part of the Matthews Range where one of Kenya's largest elephant population resides.

Arriving early morning after a two-hour drive from Sera, we're the only tourists privileged to watch a writhing throng of eager trunks reaching for their bottles at feeding time.

There are plans to release some of the 13 elephants into Sera later this year, along with Reteti's only rhino, three-month Loijupu who was abandoned at birth.

A bundle of wonder and hope, he curiously stumbles towards me and - perhaps naively - I allow him to get much closer than his elders. Nostrils flared and bottom lip curling, he's unbelievably cute.

But an instinctive defiant foot stamp is a firm reminder he's wild, belligerent and, above all, a fighter - like every black rhino today should be.

How to get there

The Ultimate Travel Company (theultimatetravelcompany.co.uk; 020 3553 2024) offers a six-night holiday from £5,237 per person, with three nights at Saruni Samburu and two nights at Saruni Rhino on a fully inclusive basis, including game viewing and rhino tracking at Saruni Rhino. Also includes a night at Ole Sereni Hotel, Nairobi, international flights from London and internal light aircraft flights.

Both KLM (klm.co.uk) and Air France (airfrance.co.uk) offer flights to Nairobi from various regional departure points via their hubs in Amsterdam and Paris. Economy fares from the UK start at £393 return, including taxes and charges.