They are grazing out in the open — hardly prime targets for a solitary cat. Big brother Ron is around, somewhere. If Julie could enlist his help in herding them toward her, they'd have a fighting chance, perhaps. Tigers, unlike lions, aren't communal hunters by nature. They move secretly under the cover of forests and scrub. The upside of being a tiger is you don't have to share the spoils. The downside is that when you dine alone, you're responsible for it all, from soup to nuts — from strategizing and stalking to swiping and inflicting the suffocation bite.

Tigers are different from lions, socially-speaking, despite that the two are remarkably similar creatures underneath their coats. Lion researchers working in East Africa believe the key to group-living for lions is being able to defend large kills from others in the wide open spaces of the Serengeti plains. It makes sense to share a zebra with close relatives rather than lose it to strangers.

In their native Asia, tigers hunt alone. But will Ron and Julie adapt to their African habitat — a considerable chunk of which is grassland — by cooperating together? Or will they hunt alone in the forests and ravines here, habitat similar to that of Asia? John Varty is eager to find out.

It's been a while since either tiger has had a successful hunt. Ron killed a warthog about 10 days ago and Julie, a bushbuck about a week ago. Tigers are gorge-feeders. Post-kill, they stuff themselves so full of meat that it's no hardship to go without for a few days, or even a week. But this morning, Julie's making whining sounds, clearly hungry. Ron appears less bothered by the empty stomach.

At 8 a.m., Julie jumps off the Land Rover and creeps to the crest of a hill.

"She's working it out," Varty whispers. "You can see she's working out what to do."

He urges Ron to join his sister: "Let's go! You guys are goofing around!" Like a cheeky child, Ron hops up into the cab of a pickup to investigate a movie camera perched on a tripod that appeared sturdy until just now.

"NO RON NO!" Varty commands, tapping Ron's shoulder with a thin white baton. The discipline stick gets Ron off the truck, but Varty's appeal to him to help Julie goes unanswered. Ron flops down in the shade of the Range Rover.

Julie, meanwhile, has tiptoed into the cover of some brush at the top of the hill and begun taking the long way around to the wildebeest herd.