Lion, leopard, elephant, buffalo and rhino. It's a hunting term from the colonial era, naming the five animals considered most dangerous to shoot on foot, which is why the list contains buffalo and not cheetah.
How hard each one is in Tanzania
Elephant. Easy. Tarangire in the dry season is remarkable for them, and the Ngorongoro Crater and the Serengeti deliver reliably.
Buffalo. Easy, and more dangerous than they look. Herds everywhere, and solitary old bulls with a famously poor temper.
Lion. Reliable. The Serengeti and the crater both have high densities, and most week-long northern trips produce several sightings.
Leopard. Genuinely uncertain. Solitary, nocturnal and superbly camouflaged. The Seronera valley's riverine woodland is the classic place, and a guide who knows the individual trees matters more than the park.
Rhino. The hard one. Tanzania's black rhino population is small and heavily protected, and the Ngorongoro Crater is realistically the only place on a normal northern itinerary. Expect a distant speck through binoculars rather than a close encounter, and treat seeing one as a bonus.
The problem with the list
People spend a week looking for five animals and drive past the interesting ones. The best mornings usually aren't a checkbox: a cheetah teaching cubs to hunt, a hyena den at dawn, a serval pouncing in long grass, vultures sorting themselves into a pecking order at a carcass.
What to look for instead
Cheetah on the southern plains. Serval and caracal, which turn up more often than people realise if you're actually looking. Bat-eared foxes. Honey badgers, if you're very lucky. Golden jackals. Dik-dik, always in pairs. And the birds, which almost everyone dismisses on day one and is photographing by day four: lilac-breasted rollers, secretary birds, ground hornbills, a thousand flamingos on a soda lake.
Tell your guide what you want
If you want the five, say so and they'll plan the week around it. If you'd rather sit with one leopard for an hour than tick three species before lunch, say that instead. Both are legitimate, and the only bad version is the guide guessing wrong for six days.
Bring binoculars. Properly.
The single biggest upgrade to a safari for the money, and the thing most people skip. One pair per person, not one shared pair, because passing them back and forth means somebody always misses it. Eight or ten times magnification is right; anything stronger is hard to hold steady in a vehicle. Half of what a guide points out is too far away to enjoy without them.
The Little Five, which is a joke worth knowing
Elephant shrew, buffalo weaver, leopard tortoise, antlion and rhino beetle. It started as a guide's gag and it's a genuinely good way to spend a slow afternoon, because looking for small things teaches you to look properly.