A lion moans from the uncharted darkness beyond your Zambezi campfire; red kangaroos dodge spinifex tussocks as they bound across the Outback; a green turtle hauls out of the Pacific beneath the stars on a Costa Rican beach.
Whatever the wildlife cliché, you needn't be a naturalist to appreciate that few things are more evocative of a place than its untamed creatures.
Today's wildlife watchers, appetites whetted by the likes of Big Cat Diary and the Discovery Channel, have blazed trails to places and experiences that were unthinkable a generation ago.
Birds of paradise in Papua New Guinea? Been there. Lemurs in Madagascar? Done that. When Peter Matthiessen wrote The Snow Leopard, after months combing the Himalayas for the world's most elusive big cat, he could scarcely have imagined that today he need only join a tour group to tick off this fabled beast.
Of course it is A-listers such as snow leopards – known to naturalists as "charismatic megafauna" – that continue to shift the most tours. An Indian wildlife itinerary is almost unthinkable without attempting to see tigers; one to Borneo implausible without orang-utans. And African tourism remains dominated by the anachronistic "Big Five": a throwback to colonial days, when the quintet in question – lion, leopard, elephant, rhino and buffalo – were reputedly the hunter's most dangerous adversaries.
The appeal of such big-hitters is understandable. Pop psychology suggests they stir in us some primal hunting instinct – or that they embody the untamed, for which our sanitised, urbanised souls cry out. Certainly, there's an undeniable thrill to an encounter with, say, elephants. Especially when the trunk comes up, the ears flap and a trumpet blast gets your knees wobbling in a novel and disturbing way.
But the risk is that your agenda shrinks to a tick list: get the snaps for the folks back home then dash on to the next one. Some African operators now promote the "little five" (elephant shrew, buffalo weaver, antlion, leopard tortoise and rhinoceros beetle) as a light-hearted foil. Pay attention to the small stuff, they are suggesting, and you'll enjoy a richer all-round wildlife experience.
It's a sound principle. Even in a teeming national park, nothing simply parades around for your viewing pleasure. It's easy to forget that those action-packed documentaries – all kills and copulation – are edited down from thousands of hours. You could, for example, spend days in the Kalahari and never see a meerkat. And that, surely, is the point. These are wild animals. Where would be the excitement if each turned up on cue as predictably, say, as a price-comparison website advert on ITV?
Mindful of the need to manage unrealistic expectations, today's wildlife guides often spend as much time explaining the ecology as they do seeking out big animals. Hence the rise of destinations such as Costa Rica or Sabah, Malaysia, where dense forest can make large mammals hard to find but an immersion in their sheer tropical profusion – the plants, insects, birds, reptiles – is just as rewarding.
But while it's all well and good appreciating the animals, do they appreciate us? Stories abound of unscrupulous operators harassing wildlife, vandalising habitats and contributing nothing in return. Conservationists argue, however, that responsible tourism can drive conservation. It gives developing nations – and, crucially, local communities – an economic incentive to protect their wildlife and natural habitats. Rwanda, for example, earns about £4m a year purely from gorilla tourism. Without people paying to see them, Africa's greatest apes might be long gone. The people around Volcanoes National Park in the former Belgian colony now have new schools and clinics, and sustainable alternatives to lopping down the forest.
Globally, guidelines are being established to keep wildlife tourism sustainable: boats must allow whales space, for example, while most national parks set aside "core zones" that are off-limits to tourists. Conscientious operators follow sustainable practice – including carbon offset schemes – while independent travellers are better informed about how to view wildlife responsibly.
And watching wildlife need not mean flying to some other hemisphere. With the hedgehogs and grey seals of Autumnwatch now outdoing big cats in the ratings, we are increasingly learning that wildlife begins at home. Only relatively recently, for instance, have we caught on to the excellent whale watching off the coasts of Britain and Ireland.
In the end, be it a red squirrel on Brownsea Island in Dorset or a red panda in Nepal, the appeal is the same: that frisson of escape that comes from sharing a moment – however fleeting – with a wild creature in its own world.
Mike Unwin is the author of '100 Bizarre Animals', published by Bradt Travel Guides (bradt-travelguides.com), £16.99
The call of the weird
Some creatures are worth seeing for their oddness alone – and none more so than these five.
Madagascar's weirdest lemur inspires much local superstition: small wonder, with its gremlin face and skeletal middle fingers. Sightings are easiest on the island of Nosy Mangabe, where it has been re-introduced. You'll need a torch, a guide and luck.
Kiwi, New Zealand
This pear-shaped, flightless national emblem boasts both the bird world's best sense of smell and proportionally its biggest egg. All five species are threatened and largely confined to island sanctuaries. Try Stewart Island for guided walks to see brown kiwis.
Giant anteater, Brazil
A monster termite guzzler, with a hosepipe face, grappling hook claws and a metre-long broom of a tail. Try Brazil's Serra da Canastra National Park for close daytime encounters.
This big, enigmatic waterbird, with its Dutch clog of a face, frequents Africa's deepest swamps and enjoys legendary status among birders. Uganda's Murchison Falls and Zambia's Bangweulu wetlands are the top spots for viewing. Take a guide, a boat and wellies.
The stick-thin jaws of the world's oddest crocodilian, are adapted for side-swiping fish and surmounted by a bulbous knob that amplifies its courtship hisses. Now very rare, your best chance are the sandy riverbanks in Nepal's Chitwan National Park.
The beauty of birdwatching is that birds are everywhere. Nonetheless, certain spectacles pack an extra punch.
Macaw clay-lick, Manu, Peru
Manu, Tambopata and a handful of other reserves in the Peruvian Amazon host one of nature's greatest colour shows, as hundreds of macaws, right, gather at exposed riverbanks. They come for sodium-rich red clay to supplement their fruity diet, and carry it away in a kaleidoscope of wings. Hides nearby make life easy for photographers.
Eagles and cranes, Hokkaido, Japan
Winter on Japan's northernmost island assembles some dramatic birds against a suitably snowy backdrop. Red-crowned cranes perform balletic, bugling courtship displays on the frozen fields, while huge Steller's sea-eagles gather on the sea ice in search of fish.
Pretty in pink, Nakuru, Kenya
The flamingos of East Africa's Great Rift Valley commute between lakes according to season. Lake Nakuru is the best known, with congregations in the hundreds of thousands turning the shoreline pink. And should you tire of flamingos, the surrounding reserve is home to 450 other species, from massive martial eagles to dazzling rollers, sunbirds and glossy starlings.