Explore Earth's Tropical Islands | BBC Earth

but the male is hesitant. Instead, it's the alpha female who takes the lead. Sounds of their splashes carry over 200 metres through the water and can draw unwanted attention. But unlike most other monkeys, proboscis are excellent swimmers. To survive here, they have evolved webbed feet. Finally, the reluctant male makes his move. But a mother and baby have been left behind. The baby must cling on for dear life. This time, the whole family have made it. Even the most vulnerable. Fiercely fought o

ver in World War Two, it's now home to three million nesting seabirds, including the biggest colony of Laysan albatross in the world. One four-month-old chick is especially hungry. Like the thousands of other albatross chicks, he's still flightless and dependent on his parents for food. But his mother is the oldest known living bird in the wild. An astonishing 67 years old. He hasn't seen her for over a week. In the searing tropical sun, he pants to cool down. And can only watch while other pare

nts return to feed their chicks. Finally, after two long weeks of waiting, the world's oldest known bird appears. Identified as Z333 on her leg band, she's more affectionately known as Wisdom. To her chick, though, she's instantly recognisable as Mum. In her extraordinary lifetime, Wisdom has flown almost five million kilometres and successfully raised 37 chicks. Today, she's surrounded by three generations of her extended family. But this exceptional great-grandmother has no time to rest, only

staying for 10 minutes before leaving to search for more food. The chick may have one of the most experienced mums in the world but his future is uncertain. Locusts. They're normally solitary insects, but when there's an abundance of crops, then numbers can reach plague proportions. These flightless hoppers can form armies a kilometre long. But they have only just begun on their path of destruction. At five weeks old, they morph into fully-fledged adults, and can take to the air in their billion

s. A swarm this size may only appear once in a decade in Madagascar. Travelling over 80 kilometres a day, they can devour 40,000 tonnes of vegetation, including the farmers' precious rice crops. On reaching the highlands, a plague is finally stopped by the heavy mountain rains. Wet wings prevent the locusts from flying, until eventually the swarm runs out of food and dies. Decken's sifaka. This youngster is three months old and already practising the vital skill of leaping. No one cluster of tre

es is large enough to sustain a whole family of hungry sifakas. This mother and son need to seek out another pocket of vegetation, possibly hundreds of metres away. They must run a deadly gauntlet. These limestone shards stand more than 100 metres tall and are sharp enough to shred human skin. But sifakas have thick, rubbery footpads and spring-like legs that can leap nine metres in a single bound. These lemurs have evolved into blade runners. Safely across, mother and son claim their reward: th

e fresh, juicy leaves they need to survive. With little to eat down here, many of Borneo's terrestrial mammals are smaller than on mainland Asia. Confined to her protected forest sanctuary, the exceedingly rare Bornean sun bear. Just over a metre long, it's the smallest bear in the world. This fallen branch is a valuable treat. Filled with wood grubs and beetles, nothing is wasted, even foul-tasting millipede. But it's not enough to sustain even this little bear. The real prize sits high above.

Guided by her exceptional sense of smell, it's the sweet scent of honey. For larger bears, this beehive may be out of reach. But being small helps defy gravity. With sharp claws and rough pads on her feet, she can ascend 40 metres higher than any other bear. To make it in Borneo's jungle treetops, this miniature acrobat has become more monkey than bear. In 1972, a pet shop imported several dozen Jackson's chameleons from East Africa. But they escaped. Slowly but surely, they found their way out

of the suburbs and up into O'ahu's forests. And that's where the trouble began. Horned males joined the escaped females. Free from predators and with an abundance of food, they began eating their way through Hawaii's unique wildlife. Invasive species like these chameleons have contributed to the extinction of over 500 native species. Attempts are now being made to recapture the chameleons, part of a much larger effort to save Hawaii's native wildlife. Even in the most unlikely places. In Hawaii'

s busiest city, Honolulu, a white tern chick is just a few days old. With no nest to protect him, he must cling to his street perch while he waits for his parents to deliver regular supplies of squid and small fish. These birds were revered by the ancient Polynesians. They knew that if they saw a white tern with a bill full of fish, it was a sure sign that land was nearby. And yet it's likely the arrival of humans wiped them out from the main islands. But now the terns are making a comeback. In

the last 60 years, their numbers have risen from a single pair to over 2,000 birds. Busy roads may help keep predators away. And trees planted within the city provide safety and prime nesting habitat. In six weeks' time, this chick will take to the air. With nightfall, the competition in the jungle intensifies, as many of Borneo's 180 species of frog now burst into song, all singing for a mate. The bigger the frog, the louder the call. But this male tree-hole frog is barely bigger than a fingern

ail. He'll need to do something special if he wants to be heard by a nearby female. She may only be metres away, but the chorus from the other frogs is deafening. This tiny male, however, has a trick. He searches for a tree hole. The size and shape of the hole are critical. He then does something remarkable. It begins with a sound soundcheck. Too low. He changes pitch. Too high. That's it. At this specific frequency, the tree hole resonates, amplifying the sound and broadcasting the call more th

an 50 metres across the forest. For a female, it's music to her ears. With superb directional hearing, she can home in on his calls. Finally, the tiny couple meet. Hidden from predators, the tree hole will go on to make an ideal nursery for their tadpoles. Tiny Labord's chameleons, only 3cm long, begin to hatch. They live for only four months, the shortest lifespan of any land vertebrate. For this young male, it's a race against time. In the dry season, there is little food, but his hatching is

perfectly timed. It's the start of the rainy season. The parched landscape is transformed into a flush of green. Just what this growing chameleon needs. As his eyes can move independently, he can spot a meal in any direction. And by locking both eyes on to a target, judge distance with deadly accuracy. With so much food on offer, the male Labord's chameleon can grow five times his size in just two months, transforming into an adult male with an eye-catching horn. A female approaches, but the mal

e has a rival. With such short lives, there's fierce competition for a chance to mate.