"On the plains of Africa, an army is on the march." "Over a million wilderbeasts are heading across the Serengeti Plains." "They face danger every step of the way, but they're heading for a massive confrontation." "Here, at the Mara River." "It's the perfect place for a surprise attack and the predators are taking their places." "Lions and leopards know every hiding place every ambush point and in the water lurk the largest crocodiles in Africa." "The trap is almost set and for this wilderbeast, it's about to be sprung." "What makes these animals risk the dangers of this crocodile-infested river ?" "And in a herd of over a million strong is life and death simply a lottery ?" "Can the time and place the wilderbeast decides to cross increase its chances of survival ?" "To find out, we'll look at the chain of events that led to this critical moment." "It's 6 months before the chaos of the crossing and the herd is in wilderbeast heaven" "Over 100 miles south of the Mara river the wilderbeasts have gathered on lush, short grass plains, to have their young." "For a wilderbeast, this is as good as it gets." "The grass here is crammed with calcium, witch gives mother's milk a lots of bottle (?" ")." "Everything a growing youngster needs for healthy teeth and bones, witch a few predators around here wouldn't mind munching on." "Wilderbeast have to grow up fast." "They can stand up 5 minutes after they're born." "Within a week, they can run 100 meters in less than 8 seconds." "They're only at risk if they get isolated." "But here the youngsters grow up in a protective forest of legs." "They're relatively safe." "With hundreds of thousands of mothers giving birth in a few short weeks," "Predators are overwhelmed." "Lush, green pastures, safety in numbers, the big question is why do they ever leave ?" "Especially to come here" "You have to wonder whether they've read the brochure" "This is the Mara river." "It flows even at the driest times of year but this predictable water supply is attracting the wrong sort of crowd." "These are the biggest crocodiles in Africa." "They've been around since the dinosaurs." "Nothing evolved to take their place, because nothing can make a killing like a croc." "Even so, some haven't had a substantial meal for months." "And big cats prowl the banks." "Their young aren't natural athletes, they couldn't keep up on the long wilderbeast migration." "Instead, both leopards and lions choose what they hope would be a good spot to settle down." "Here, at the Mara River, they have great views plentiful water, and if they're lucky, the imminent arrival of 160,000 tons of self-propelled stake." "But no one can predict whether the wilderbeast will cross here or even if the massive herd will get this far." "With Africa's biggest predators waiting to greet them, and a new generation getting stronger all the time, you could hardly blame the wilderbeast if they decided to call the whole thing off." "4 months to impact and the wilderbeasts are about to turn tail, and leave what seems like heaven." "But why ?" "They are victims of their own success." "With the arrival of the youngsters, the population has reached critical mass." "Wilderbeasts need to eat grass for 16 hours a day and with the short rainy season over, it can't grow fast enough." "Like a plague of hairy locusts, they've eaten themselves out of house, and home." "The whole herd must leave in search of green grass and water." "Those babies born late, are most at risk." "For the first few days of life, the calf is slower than its mother." "It's these youngsters that hyenas prefer." "No strugglers, no doodlers, no one can afford to be left behind." "It's a mass exodus." "There are so many animals, that from the air the megaherd looks like a dog's stain on the landscape." "But head toward the Mara River ?" "Where the calculating killers patiently wait." "It's one month to impact and the height of the dry season is approaching." "The river has animal magnetism and some uneasy neighbors are forced to become better acquainted." "Even big cats can loose their calculating cool." "Attacking a croc is no way to sort out the hunger pains." "Even if they survive the powerful jaws the croc has a bony amour-plated hide." "This cat food comes in its own tin and no one here has an opener." "Just like a family dog panting cools the leopard's body." "Tired moms are a soft target playground and pitstop combined." "At 4 months old, the cubs are almost wind." "And mammal moms are special engineered to produce nutritious milk even if their own health decline." "But there's still no herd on the horizon." "The wilderbeast may not even cross here." "All the predators can do, is wait." "The plains have long since turned from the salad bowl into a dust bomb." "As the dry season advances the wilderbeasts are forced to march ever onward." "Their lives are a constant search for green grass and water." "Without them, they grow weak." "And around here, the weak don't survive." "On their long journey, many wilderbeasts will fall." "But for a lion's pride, the time of plenty is brief." "Their cubs can't travel far." "The wondering wilderbeasts will soon be out of reach" "They must take advantage while they can." "Although many wilderbeasts will loose their lives, nothing can stop the march of the megaherd." "They must move one, in their constant search for food leaving this lion pride behind." "When it comes to finding grass and water, wilderbeasts seem to have a sixth sense." "Maybe they see distant lightning, or hear the rumble of the thunder." "Whatever the reason, the advance of the dry season pushes them steadily towards the Mara River." "But those that have lived long enough to see it, remember a place with lush grass even in the driest time of year." "But to reach this paradise" "They first have to cross the river of death." "The lush pastures beyond the Mara River ows their existence to some unique local geography." "Sitting alongside them, is a lake the size of Ireland" "Lake Victoria is so big it spans three countries." "The hot African sun evaporates its water turning it into cloud." "When these clouds hit the area around the Mara River they fall as rain." "At the height of the dry season this natural rain-making machine turns the area into a wilderbeast paradise." "Water may turn scorched Earth into lush pastures but it turns the river into a murderous torrent." "Its changing mood, curves and crossing points dictate the battlefield in witch the wilderbeast big cats and crocs will meet." "The Mara River has a life of its own." "And with the coming of the rain, it's developing a bit of an attitude." "And on the distant horizon a sight to give every hungry predator hope." "The wilderbeasts have nearly made it" "But as they approach, the big question is" "Where to cross ?" "Some crossing points are visible for miles and the lie of the land follows the wilderbeasts towards them." "for a predator, there's no use pretending you're not here" "The confrontation is inevitable." "It's just a matter of time." "This small group has managed to arrive a day earlier than the main herd." "They're desperate for water, but understandably nervous." "Throughout their journey they sought safety in numbers safest thing to do would be to wait for the other but the lush green grass is on the other side of the river." "Will it prove irresistible ?" "The advance party looks set to cross alone." "Conditions are perfect." "But not for the wilderbeast." "A blow from a wilderbeast hoof can knock a crock out of action permanently." "But this group is so small, the crocs have less chance of getting injured." "The crocs work as a team." "Twisting hunks of flesh from the bone is easier when someone is holding the other end." "Today, reptiles rule." "And with the rain continuing to fall, the river is still rising." "Tomorrow, when the megaherd arrives it looks set to be even worse." "On far bank, the handful of surviving wilderbeasts lack safety in numbers." "The broke the rule :" "Never travel alone." "Dawn." "For some of these wilderbeasts it will be the last they ever see." "Over night the megaherd has arrived." "And as the numbers mount, so does the pressure." "Wave upon wave of wilderbeasts, pushing from the back forcing the front runners dangerously close to the edge." "They're tired, scared and desperate for food but no one wants to be the first to leap." "Something's got to give." "The front runners can't hold back for ever." "The time to cross has arrived." "Lush green pastures are just a few feet away but these last few feet will prove more deadly than anything this wilderbeast has faced in its six months trek." "Ranks of crocodiles still wait in the water." "But this time, the wilderbeast have numbers on their side." "They're preparing to storm the river en masse." "Crocodiles may be thick-skinned, but they are not stupid." "They don't risk a blow from the wilderbeasts hooves." "Thos in the middle of the herd are completely safe." "Only those on the sidelines are at risk." "But nothing can stop the main assault." "Things are going well." "Then someone throws a spanner in the wilderbeast's works." "The leopard launches an attack." "Although she misses completely, panic spreads through the herd and they hurry along the bank, in search for a safer entry point." "The leopards take advantage of the confusion." "It's only a young wilderbeast, but it will be enough to give her growing cubs food for days." "But this simple act" "Is destined to have an unexpected and catastrophic effect." "The wilderbeast have found another entry point." "But leap before they look." "It's only when the front runners reach the opposite bank that they realize there's no way out." "But thousands are following in their lead." "It's gridlock." "All their lives, the herd has protected them." "Stick together, stay safe." "But here, the rule they've lived their lives by, is failing them." "Every year at the crossing, more wilderbeast die under the hooves of the herd than in the jaws of the predators." "But for every wilderbeast that falls at the river thousands survive, to reach this paradise." "A wilderbeast's life is a never-ending search for green grass and water." "And, as their numbers grow, that search must take them further than ever from their birthplace." "As far as the Mara River" "And for those who survive, beyond that." "In a few months the dry season will be over, and the wilderbeast will be able to head back, once more to the place of their birth." "For them, there's nothing like the nutritious green grass of home." "But for now, the wilderbeast have all they can eat." "And the lions, in this wilderbeast paradise can make hay" "while the sun shines."