If I were a lion I'd be worried. At least a dozen Maasai warriors in battledress are bearing down on us, armed with sticks.

The noise they make is scarcely human – deep guttural grunts and throaty humming punctuated by high-pitched yelps. The jungle is moving towards us – an African Birnam Wood. The warriors are draped in bright colours – mainly blood red. But more than one is wearing fierce pink. Real men wear fuchsia.

There is no time to dwell on the fashion details as we are swept into the swirling, bobbing welcoming party at Ngerende, a safari lodge in the northern Mara. I have mixed feelings about the human zoo side of such spectacles, but keep my caveats to myself as the men do their thing with evident enthusiasm. Who am I to spoil their party?

We are in the Maasai heartland. The lodge is in an area defined as a "conservancy" bordering the national park from which the tribes were displaced, some would say dispossessed. The Maasai are not permitted to live in the park or graze their domestic animals within it, but here they cohabit with the wildlife and are encouraged to live and let lions live. That's not always easy when the big cats help themselves to cattle. The angry herdsmen tend to exact swift revenge, but they are being given incentives to be more tolerant. Every safari tourist in the conservancy pays a tax that goes into local coffers to be disbursed as the community decides. Call it the Lion Economy.

Ngerende Island Lodge is not actually located on an island but on a deep kink in the Mara River that is in the process of becoming an oxbow lake. It is Kenyan owned and run and makes a point of "empowering", as they put it, local communities – recruiting 70 per cent of staff from the Maasai. It has just seven rooms, all of them part-bungalow, part-tent, perched on the steep banks of the river. Mine is open to a full-length terrace during the day and made cosy and less inviting to insects and other unthinkables in the evening when canvas flaps are rollered down. The look is cool and contemporary without crossing into design fetishism.

Mercifully, there's no Wi-Fi, no iPod dock, no DVD or TV; the accommodation has its own open-air bath, brick fireplace, butler service and private hippo – who announces his presence in the opaque water below with a visceral harrumph as I am unpacking.

At this time of the year, the conservancy is packed with large animals. The famous wildebeest migration of the Mara-Serengeti ecosystem brings herds north from Tanzania in search of fresh grass and with them comes a travelling circus of fauna; some migrating peacefully alongside, others, higher up the food chain, here for the predator's equivalent of Christmas.

Almost as soon as we leave the compound on a game drive we are mobbed. The extraordinary range of life forms is bewitching: giraffes sway elegantly, propping tiny heads on their freak-show bodies; impala; Thomson and Grant gazelle show off their go-faster lines and corkscrew headgear; eland (the largest antelope) blink in the morning sun; and hundreds of zebras give the impression that Bridget Riley has waltzed through the savannah with a giant paint brush.

In such company, wildebeest are the comedy animals of the great African plains. They look a mess. When in herds, it's hard to tell where one mangy animal ends and another begins. When you do catch them alone they look like cow-sized rugs in the process of unravelling. They make a grunting chorus of honks, ohs, oohs and aahs – some interrogative, others assenting, some snoring. Like a gentlemen's club after a well-lubricated dinner. You can't take them seriously. Their main function is to be the larder. Where there are wildebeest, there be lions.

The radio in the Land Cruiser crackles and our dreamy progress takes an urgent turn. Stephen, the driver and guide, revs the engine, churning up the wet Black Cotton (the name given to the dark mud here). We are in pursuit of cats. We find them where three other safari vehicles have stopped. The conservancy is considerably less crowded with tourists than the national park. Here, at least, the cats have a chance to behave as nature intended.

These lions are doing plenty of that. They are a mating couple, too loved-up to pay any attention to voyeuristic humans or their noisy machines. They stride boldly out of the bush straight at us, looking like a pair of feline gunslingers, and choose to get intimate just inches in front of the Cruiser's bumper. Lion lovemaking is accompanied by vicious snarling and biting and is over in seconds. It sounds terrifying. But what they lack in finesse they make up for in frequency, mating up to 40 times a day.

From my terrace back at the lodge I spot a crocodile sunbathing on the opposite bank. The hippos are also there taking in the rays. Half an hour later I hear the tinkling of bells and children's voices on the far bank. Maasai children and some of their goats are frolicking where a few minutes earlier the crocodile was parked. Baby goats scramble down to the water's edge for a drink. I tense up, waiting for a croc to lunge from the murk. It doesn't happen. We are in strange territory, somewhere between a pastoral idyll and nature red in tooth and claw.

The next morning the Mara is a crime scene. We find numerous fresh wildebeest corpses within yards of each other. The lions, says Stephen, are killing "just for fun". The carcasses don't seem to have been touched by the cats. A lone jackal circles the kills protectively and a bored-looking hyena lopes by to check them out. Both are only going through the motions; neither is remotely interested in eating.

We are on our way to a crossing point on the Mara River – where the herds gather before heading back to the Serengeti plains. The topography of the plains is familiar enough from BBC wildlife blockbusters. The vast space, the yawning sky, the umbrella acacias, and the stunning cloudbursts. What the Attenborough-fronted documentaries don't prepare you for is the surfeit of death.

There are carcasses everywhere, creating bloated reefs of rotting flesh in the river. All part of nature's balance, we are assured, a food chain that sustains the ecosystem. But the logic seems stretched. At this time of year the crocs are fat and sated. We don't see them harassing the herds. The inescapable conclusion is that the animals died in the river scramble, which (as survival strategies go) seems pretty stupid.

On the north bank, wildebeest and zebra pace fearfully, edging up to the water and retreating. This goes on for a couple of hours in front of a car park of safari vehicles lined up rather ghoulishly to watch the mayhem. Eventually, we are rewarded with a bona fide zebra crossing. It's an orderly affair with a few dozen zebras making it over without casualties. The wildebeest are still dithering when we leave.

On the way back we come upon one wildebeest that definitely won't be going back south. It has a lioness poking around deep within its ribcage. Parked up almost within touching distance I can hear the lioness going about her meal in bone-crunching, sinew-shearing detail. Her blood-smeared face emerges from inside the carcass with the heart of the wildebeest clamped in her jaws. It is swallowed whole in one satisfied gulp. She pauses for a rest and her mouth is open. She looks every inch the masterful hunter, but it is clear that she has lost one of her vital canines in her battles. Wildebeest are perhaps not quite the easy meat they seem.

The sun is setting. The 360-degree panorama from the flat horizons of the south to the escarpments of the north is thick with dots, as if the Mara has been sprayed by a meteorite shower. But the dots are animate. Each tiny speck is alive – they are wildebeest beyond number. They die in their thousands during the migration, but come back in force every year.

It dawns on me that it isn't the glamour animals – your lions, elephants and giraffes – that are the most successful here. Nature is playing a joke on us; it's not the survival of the biggest, the sleekest or the strongest that counts. By my unscientific reckoning, wildebeest must outnumber all the other large mammal species on the great plains put together by about 500 to one. Somehow these daft creatures, who appear to have been designed by a dysfunctional committee, are the true masters of the Mara. Mange rules.

Compact Facts

How to get there

Kenya Airways (020-8283 18181; kenya-airways.com) flies daily from London Heathrow to Nairobi with extra daylight flights at the weekend. Returns in economy class start at £506, business class from £2,161. Sankha Guha stayed at Ngerende Island Lodge (ngerende.com), where doubles start at £583 per person per night, based on two sharing, between 1 November and 19 December. The price includes return domestic flights to the lodge, full-board, two extended game drives, a guided bushwalk, game viewing at the Olchoro Conservancy, sundowners, a Masai village visit and one half-hour massage. Tribe (tribe- hotel.com) in Nairobi offers rooms from $285 (£183) per night.

Further information