0:00:00 > 0:00:03The world is full of extraordinary animals.
0:00:05 > 0:00:09But how well do we really understand them?
0:00:09 > 0:00:12How do they really think and feel?
0:00:13 > 0:00:17To find out, a team of spy creatures is going undercover.
0:00:19 > 0:00:21They not only look like part of the family,
0:00:21 > 0:00:24they behave like them, too.
0:00:26 > 0:00:28Armed with the latest camera technology...
0:00:30 > 0:00:32..they are going to travel the globe...
0:00:33 > 0:00:37..to understand the true nature of the animals they meet
0:00:37 > 0:00:41and reveal how intelligent they really are...
0:00:43 > 0:00:46..how badly behaved they can be...
0:00:48 > 0:00:51..how important friendship is to them...
0:00:53 > 0:00:54..and if it's possible
0:00:54 > 0:00:57that they can truly love each other.
0:00:57 > 0:01:01What they discover will change our perception of animals forever.
0:01:04 > 0:01:09Perhaps they are more like us than we ever believed possible.
0:01:16 > 0:01:17SCREECHING
0:01:20 > 0:01:23Animals live complex lives,
0:01:23 > 0:01:26but how sophisticated are their emotions?
0:01:30 > 0:01:34On the African savanna lives one of the world's most intelligent
0:01:34 > 0:01:37and family-focused animals -
0:01:37 > 0:01:38the wild dog.
0:01:41 > 0:01:44In this pack, all the puppies belong to just one mother,
0:01:44 > 0:01:46but are showered with affection
0:01:46 > 0:01:49by every member of the extended family.
0:01:53 > 0:01:57When the adults go hunting, a new pup makes an appearance.
0:02:00 > 0:02:03This is spy pup. The only giveaway
0:02:03 > 0:02:05is the camera in his eye.
0:02:08 > 0:02:09YELPING
0:02:09 > 0:02:12He is here to film the emotional dynamics of pack life,
0:02:12 > 0:02:16but first, he must be accepted by the pups.
0:02:17 > 0:02:20They could easily rip him to pieces...
0:02:23 > 0:02:27..so he mimics their body language, to make them feel at ease.
0:02:31 > 0:02:33He uses the play bow.
0:02:33 > 0:02:36It's a universal invitation to have fun.
0:02:45 > 0:02:47He's won them over,
0:02:47 > 0:02:50despite his slightly-strange smell.
0:02:55 > 0:02:59The adults, however, may be harder to convince.
0:03:05 > 0:03:08So, he makes a submissive gesture and wags his tail.
0:03:13 > 0:03:15GROWLING
0:03:24 > 0:03:28Now accepted, he soon gains the most intimate view
0:03:28 > 0:03:30of wild dogs ever seen.
0:03:44 > 0:03:48The pups beg for food by licking the adults' mouths.
0:03:48 > 0:03:51Fresh meat caught just for them.
0:03:57 > 0:04:00With survival depending on teamwork,
0:04:00 > 0:04:03affection strengthens family ties.
0:04:06 > 0:04:10Unfortunately, it's not just spy pup that's watching them.
0:04:14 > 0:04:15BARKING
0:04:19 > 0:04:23The strength of their love is about to be tested.
0:04:31 > 0:04:34Lions regard wild dogs as rivals.
0:04:42 > 0:04:45She'll kill the pups, if she can.
0:04:58 > 0:05:01Spy pup can only lay low and observe.
0:05:16 > 0:05:19The lioness picks up the smell of the den.
0:05:25 > 0:05:27The dogs try to divert her attention.
0:05:27 > 0:05:29WHINNYING
0:05:31 > 0:05:35But with pups in her sight, she won't be easily distracted.
0:05:40 > 0:05:42The pack keeps up the diversion.
0:05:45 > 0:05:48But it's the desperate mother who decides to risk all...
0:05:53 > 0:05:53..goading the lioness to attack her.
0:05:53 > 0:05:57..goading the lioness to attack her.
0:06:15 > 0:06:17Over and over, she teases the lion,
0:06:17 > 0:06:19while the pack provides backup.
0:06:31 > 0:06:35After 40 minutes of relentless pressure,
0:06:35 > 0:06:38the exhausted lioness accepts defeat.
0:06:41 > 0:06:46Spy pup had a ringside view of this extraordinary encounter.
0:06:46 > 0:06:51And in the aftermath, the pups are reunited with their mother.
0:06:54 > 0:06:58Although family affection runs deep,
0:06:58 > 0:07:00nothing competes with the love of a mother.
0:07:05 > 0:07:05After the lion's visit, it's her that cleans the den.
0:07:05 > 0:07:10After the lion's visit, it's her that cleans the den.
0:07:10 > 0:07:14For her pups, it's a chance to enjoy the dust bath.
0:07:22 > 0:07:24Even spy pup joins the fun.
0:07:45 > 0:07:48A mother's love is so fundamental,
0:07:48 > 0:07:52could it be found in a relic from a prehistoric age?
0:07:58 > 0:08:00In Uganda, this Nile crocodile
0:08:00 > 0:08:04is coming ashore for a very important event.
0:08:05 > 0:08:09Her babies are about to hatch.
0:08:18 > 0:08:22Sharing her nest are some very special hatchlings.
0:08:25 > 0:08:29Ones with cameras in their eyes. They are here to record
0:08:29 > 0:08:33the relationship between a mother crocodile and her young.
0:08:38 > 0:08:41The spy hatchlings have been filming her for days,
0:08:41 > 0:08:43as she waits for her real young to arrive.
0:08:44 > 0:08:46CAWING
0:08:47 > 0:08:50The calls of her babies synchronise their hatching,
0:08:50 > 0:08:54encouraging the whole brood to emerge at once.
0:09:00 > 0:09:02They are also cries for her attention.
0:09:08 > 0:09:10For three long months,
0:09:10 > 0:09:12she protected her eggs day and night,
0:09:12 > 0:09:14as she waited for this moment.
0:09:24 > 0:09:27Now, she meets her babies for the first time.
0:09:38 > 0:09:40They are delicate and vulnerable.
0:09:42 > 0:09:45GROWLING
0:09:46 > 0:09:50But they are not safe here. She must get them to water.
0:09:51 > 0:09:54Her solution is extraordinary.
0:10:05 > 0:10:09Despite having the most powerful bite in nature,
0:10:09 > 0:10:11she carefully gathers them in a throat pouch,
0:10:11 > 0:10:13beneath a stockade of deadly teeth.
0:10:15 > 0:10:18She is as gentle as a croc could ever be.
0:10:32 > 0:10:36Safe in her care, tails dangling between her teeth,
0:10:36 > 0:10:38she takes them to water.
0:10:55 > 0:10:57She won't enjoy her babies' company for long.
0:11:00 > 0:11:03Crocodiles can have 80 hatchlings...
0:11:04 > 0:11:08..and another batch is crying for her attention.
0:11:08 > 0:11:10CAWING
0:11:17 > 0:11:19She won't leave any behind.
0:11:22 > 0:11:24Even spy hatchling.
0:11:56 > 0:12:01Safe in her cavernous mouth, all survive unscathed.
0:12:06 > 0:12:08And spy hatchling is still filming.
0:12:15 > 0:12:17They still need her protection.
0:12:17 > 0:12:20Even in the water, just one in ten survive...
0:12:22 > 0:12:25..for danger is everywhere.
0:12:27 > 0:12:29A grey heron.
0:12:31 > 0:12:34He has the pick of the bunch.
0:13:05 > 0:13:09Crocodiles have changed little since the age of the dinosaurs,
0:13:09 > 0:13:12but their maternal care is anything but primitive.
0:13:15 > 0:13:18She'll protect her babies for the next two months.
0:13:22 > 0:13:25Such care becomes stronger when whole families are involved.
0:13:30 > 0:13:34African elephants show a much more developed sense of love.
0:13:37 > 0:13:41Their extended family is made up of related females,
0:13:41 > 0:13:43led by a wise old matriarch.
0:13:43 > 0:13:47She holds the wisdom of the generations
0:13:47 > 0:13:49and this needs to be passed on to all.
0:13:53 > 0:13:56To infiltrate the herd, a new spy creature is needed.
0:13:58 > 0:14:00One based on a bird that lives among them.
0:14:03 > 0:14:08This is spy egret, complete with a filming eye.
0:14:09 > 0:14:13The first challenge will be surviving the initial encounter.
0:14:17 > 0:14:20It could be a brief assignment.
0:14:20 > 0:14:22CAWING
0:14:22 > 0:14:25He is facing 40 tonnes of unstoppable herd.
0:14:46 > 0:14:48His first test over,
0:14:48 > 0:14:50it's now down to business.
0:14:52 > 0:14:56As well as spy egret, there are other cameras covering the action.
0:14:59 > 0:15:04Spy tortoise can, quite literally, get under the elephants' feet.
0:15:26 > 0:15:30The cameras soon capture something remarkable.
0:15:36 > 0:15:40A vulnerable new arrival, less than an hour old.
0:15:43 > 0:15:46His mother must help her new-born to his feet.
0:15:53 > 0:15:56It's the start of the most important relationship of his life.
0:16:07 > 0:16:09His first steps are a challenge.
0:16:28 > 0:16:32The bond between them will be complete when he finally suckles.
0:16:34 > 0:16:36Easier said than done.
0:16:41 > 0:16:43His mother gently guides him to the spot.
0:16:50 > 0:16:52It's time to meet the relatives.
0:17:03 > 0:17:04It's a big occasion.
0:17:04 > 0:17:08Each member of the family wants to introduce themselves.
0:17:12 > 0:17:16They will all play a role helping him grow up.
0:17:26 > 0:17:29For now, the attention is overwhelming.
0:17:44 > 0:17:47But in the coming years, he'll learn all he needs to know
0:17:47 > 0:17:51for his survival from these loving females.
0:17:58 > 0:18:02The babies of some animals have to find their place
0:18:02 > 0:18:04in even larger animal families.
0:18:10 > 0:18:12This temple in Rajasthan
0:18:12 > 0:18:16is home to a troop of 120 Indian languors,
0:18:16 > 0:18:19made up of related females and their offspring.
0:18:20 > 0:18:25They are the most gentle and affectionate monkeys in the world.
0:18:25 > 0:18:29It's a sisterhood with an unusual system of childcare.
0:18:34 > 0:18:37To see how this works in practice,
0:18:37 > 0:18:41a spy baby monkey is joining the family -
0:18:41 > 0:18:45complete with camera eye and a range of life-like movements.
0:18:45 > 0:18:50The plan is to blend subtly into the crowd.
0:18:51 > 0:18:54But the monkeys have other ideas.
0:18:57 > 0:18:59They are more than a little suspicious
0:18:59 > 0:19:01of the stranger in their midst.
0:19:06 > 0:19:08She's creating such a stir,
0:19:08 > 0:19:11every monkey in the neighbourhood pays her a visit.
0:19:14 > 0:19:18Her camera reveals the extraordinary athletic prowess
0:19:18 > 0:19:20of these lively monkeys.
0:20:10 > 0:20:12To escape the pandemonium,
0:20:12 > 0:20:15the mother has set up a baby and toddler group
0:20:15 > 0:20:17in a quiet part of the temple.
0:20:18 > 0:20:22But looking after baby is a full-time occupation.
0:20:22 > 0:20:25So, once they are three weeks old, if Mum wants a break,
0:20:25 > 0:20:30she has a solution - employ a teenage baby-sitter.
0:20:32 > 0:20:35As these young females develop feelings of love and care,
0:20:35 > 0:20:37they just want to hold a baby.
0:20:39 > 0:20:43It's an arrangement that gives the mums a break.
0:20:45 > 0:20:47A chance to be pampered and groomed.
0:20:50 > 0:20:53She may have a designated baby-sitter, but here,
0:20:53 > 0:20:56every young female wants to play mum.
0:21:09 > 0:21:11When everyone's had a go,
0:21:11 > 0:21:14there's always one left holding the baby.
0:21:14 > 0:21:16It's a serious responsibility,
0:21:16 > 0:21:19but the novelty soon wears thin,
0:21:19 > 0:21:22especially when everyone else is having all the fun.
0:21:29 > 0:21:32The baby-sitter decides to join the game...
0:21:34 > 0:21:37..while the baby clings on for dear life.
0:21:55 > 0:21:58But some challenges test the baby's grip to the limit.
0:22:00 > 0:22:04An almost sheer drop of 20 metres.
0:22:06 > 0:22:10The baby-sitter is oblivious to the danger.
0:22:19 > 0:22:21For the baby, a final indignity.
0:22:21 > 0:22:23SQUEALING
0:22:25 > 0:22:29Time for the mother to reclaim her infant.
0:22:30 > 0:22:33The baby-sitter wants a break, too.
0:22:33 > 0:22:38There are plenty more volunteers, but for both baby and mother,
0:22:38 > 0:22:40enough is enough.
0:22:48 > 0:22:50It seems traumatic,
0:22:50 > 0:22:53but this is how teenagers learn the parenting skills
0:22:53 > 0:22:54they'll need in the future.
0:22:58 > 0:23:00There's no shortage of love here,
0:23:00 > 0:23:03even if, at times, it's tough love.
0:23:15 > 0:23:17The prairies of North America,
0:23:17 > 0:23:20home to an animal with a surprisingly-loving nature.
0:23:27 > 0:23:30This inquisitive soul is the prairie dog.
0:23:33 > 0:23:34He has a new neighbour.
0:23:35 > 0:23:36Spy prairie dog.
0:23:42 > 0:23:45CHIRPING
0:23:45 > 0:23:48Everyone's curious to see the new arrival.
0:23:59 > 0:24:03They live in towns, made up of around 20 family groups.
0:24:05 > 0:24:09In these wide open spaces, everyone relies on each other
0:24:09 > 0:24:10to watch for danger.
0:24:13 > 0:24:16So, to strengthen their family connections,
0:24:16 > 0:24:19they have an endearing way to express their affection.
0:24:20 > 0:24:22Kissing.
0:24:23 > 0:24:24Like a human kiss,
0:24:24 > 0:24:28it's thought to encourage the bond of love and release oxytocin -
0:24:28 > 0:24:31a pleasure hormone that floods the brain.
0:24:38 > 0:24:42It also helps identify family members
0:24:42 > 0:24:44and strangers from out of town.
0:24:46 > 0:24:50But when a rival male blatantly steals a kiss,
0:24:50 > 0:24:52it doesn't go down well with the head of the family.
0:25:06 > 0:25:10The cheating female wisely hides, as fur flies.
0:25:41 > 0:25:43Love rival gone,
0:25:43 > 0:25:45the prairie dogs regroup,
0:25:45 > 0:25:49with an enthusiastic display called a jump-yip.
0:25:49 > 0:25:53The jump-yip shows the colony is alert and on guard.
0:25:53 > 0:25:56It also reinforces its unity,
0:25:56 > 0:25:59ensuring everyone is on the same wavelength.
0:26:00 > 0:26:03Even spy prairie dog gives it a go.
0:26:03 > 0:26:05CHIRPING
0:26:41 > 0:26:43CHIRPING
0:26:46 > 0:26:48BELLOWING
0:26:48 > 0:26:51Back on the African savanna,
0:26:51 > 0:26:54the new-born elephant is on the move
0:26:54 > 0:26:57and he now needs the protection of his family more than ever.
0:27:02 > 0:27:04The spy creatures are on duty, too.
0:27:18 > 0:27:22As they travel, the mother uses her tail to make sure her baby
0:27:22 > 0:27:24is always in touching distance...
0:27:26 > 0:27:30..for danger can come from the most unexpected places.
0:27:30 > 0:27:33And wild dogs can be a threat,
0:27:33 > 0:27:36especially when they have their own pups to protect.
0:27:39 > 0:27:43For now, they are blissfully unaware that the elephants are close.
0:27:43 > 0:27:45The pups are constantly playing,
0:27:45 > 0:27:50building the social skills they need to be fully part of the pack.
0:27:51 > 0:27:53ELEPHANT BELLOWING
0:27:53 > 0:27:55But the elephants are getting closer.
0:27:55 > 0:27:57They could easily destroy the den and crush the pups.
0:27:58 > 0:28:02The dogs advance, to meet the threat.
0:28:24 > 0:28:27Wild dogs are effective killers,
0:28:27 > 0:28:29able to take down a new-born elephant.
0:28:30 > 0:28:35But their only concern now is the safety of their own young.
0:28:35 > 0:28:38Stragglers are rounded up.
0:28:40 > 0:28:43The elephants are equally concerned for their own baby.
0:28:45 > 0:28:48They shepherd him behind a protective wall of legs.
0:28:50 > 0:28:54The dogs create their own barrier between the elephants and the den.
0:28:55 > 0:28:56It's a showdown.
0:29:00 > 0:29:02The matriarch leads the charge.
0:29:02 > 0:29:03BELLOWING
0:29:09 > 0:29:12She's the most experienced member of the family.
0:29:25 > 0:29:27As the conflict escalates,
0:29:27 > 0:29:30the elephants put on a united show of strength...
0:29:32 > 0:29:35..with the baby hidden behind a moving barrier of legs.
0:29:50 > 0:29:54Eventually, the two sides accept an uneasy truce.
0:29:56 > 0:30:00Both loyal and loving families know there's too much to lose
0:30:00 > 0:30:02from further confrontation.
0:30:07 > 0:30:10With spy tortoise now fully accepted by the herd...
0:30:12 > 0:30:15..the elephants bring him along for the ride.
0:30:22 > 0:30:24Albeit, a brief one.
0:30:32 > 0:30:35The affection that binds families together may be strong,
0:30:35 > 0:30:39but the bond between courting couples is in different realm.
0:30:41 > 0:30:44In southern Kenya, love is blossoming.
0:30:46 > 0:30:48This male red-billed hornbill
0:30:48 > 0:30:52has found the perfect spot to bring up a family.
0:30:53 > 0:30:56His mate is never far away.
0:30:59 > 0:31:01He performs a little dance,
0:31:01 > 0:31:03to entice her to take a closer look.
0:31:13 > 0:31:16She shows her approval by starting to spruce the place up.
0:31:22 > 0:31:26They now face a challenge that will test their commitment to the limit.
0:31:30 > 0:31:31They set to work, gathering mud -
0:31:31 > 0:31:33a central element to their plan.
0:31:48 > 0:31:48Their aim is to make the entrance smaller.
0:31:48 > 0:31:51Their aim is to make the entrance smaller.
0:31:56 > 0:31:59They also add poisonous millipedes to the mix,
0:31:59 > 0:32:04creating an insect repellent that keeps nest-raiding pests at bay.
0:32:12 > 0:32:16The hole is shrinking fast, so before it gets too small,
0:32:16 > 0:32:18the female must move in.
0:32:18 > 0:32:23This tiny chamber will become her home for the next 12 weeks.
0:32:24 > 0:32:26She's a willing captive,
0:32:26 > 0:32:29even using her own droppings to help narrow the hole.
0:32:31 > 0:32:35She now relies on her mate to deliver more building materials.
0:32:37 > 0:32:41Working as a team, the female narrows the entrance from within.
0:32:41 > 0:32:44Their plan is to make a prison cell,
0:32:44 > 0:32:49but one purely for her protection, as it keeps predators, like snakes,
0:32:49 > 0:32:50from entering.
0:32:53 > 0:32:57Soon, the hole is reduced to a mere slit,
0:32:57 > 0:33:00just big enough to squeeze in supplies.
0:33:05 > 0:33:07Eventually, the eggs are laid.
0:33:09 > 0:33:12Among her clutch is a special spy egg,
0:33:12 > 0:33:17one that will record the next stage in this incredible story.
0:33:19 > 0:33:21As the weeks go by,
0:33:21 > 0:33:25her mate's only concern is to keep his partner well fed.
0:33:25 > 0:33:28She is completely dependent on him.
0:33:29 > 0:33:35He brings her up to 20 large insects each day, while she incubates.
0:33:37 > 0:33:40But what goes in, must come out.
0:33:42 > 0:33:44Nest hygiene is essential.
0:33:53 > 0:33:5725 days after laying, the moment has arrived.
0:33:57 > 0:33:59CHIRPING
0:33:59 > 0:34:00She has a brood of three,
0:34:00 > 0:34:03plus one adopted chick(!)
0:34:03 > 0:34:06Spy egg has become spy hatchling.
0:34:07 > 0:34:11One chick takes him under her wing.
0:34:13 > 0:34:16With more mouths to feed, the male is in overdrive,
0:34:16 > 0:34:19finding at least 70 insects each day.
0:34:25 > 0:34:27They have voracious appetites...
0:34:28 > 0:34:31..but at least one beak doesn't need feeding.
0:34:33 > 0:34:37The mother divvies up the food between her growing brood
0:34:37 > 0:34:38as best she can.
0:34:43 > 0:34:46But after being cooped up for over two months,
0:34:46 > 0:34:49the lack of space and constant quarrelling
0:34:49 > 0:34:52is getting too much for her.
0:34:52 > 0:34:54She starts to chisel her way out...
0:34:57 > 0:34:59..testing the hole for size.
0:35:03 > 0:35:06To keep her babies safe, it must stay predator-proof.
0:35:09 > 0:35:13It seems an impossible squeeze, so easy to get stuck.
0:35:28 > 0:35:29Freedom.
0:35:33 > 0:35:36The chicks instinctively use spittle and droppings
0:35:36 > 0:35:38to close up the entrance again.
0:35:42 > 0:35:45Now, the hard work can be shared.
0:35:45 > 0:35:48Each chick needs one insect every ten minutes.
0:35:48 > 0:35:51One bird alone couldn't keep up with demand.
0:35:51 > 0:35:54Spy chick even gets a mouthful.
0:35:56 > 0:35:58But, of course, he shares it around.
0:36:01 > 0:36:05The parents will feed their chicks for another three weeks,
0:36:05 > 0:36:07until they are ready to fledge.
0:36:09 > 0:36:14Few birds show such dedication. It's the ultimate expression of trust.
0:36:18 > 0:36:22They'll remain faithful for their entire lives.
0:36:24 > 0:36:27Not all partners show the same devotion.
0:36:35 > 0:36:37The cold wastes of Antarctica.
0:36:46 > 0:36:48For Adelie penguins,
0:36:48 > 0:36:52the challenges start the moment they arrive from the ocean, to breed.
0:36:54 > 0:36:56The males race to their nesting grounds,
0:36:56 > 0:36:58desperate for a head start on their rivals.
0:37:01 > 0:37:02As soon as they arrive,
0:37:02 > 0:37:07the quarrels begin over who gets the best nest sites.
0:37:16 > 0:37:19Spy Adelie enters the fray.
0:37:22 > 0:37:25But to film their complicated love life,
0:37:25 > 0:37:27it's vital he fits in.
0:37:28 > 0:37:32His courtship display makes him one of the gang,
0:37:32 > 0:37:33as they wait for their mates to arrive.
0:37:37 > 0:37:41The females are fussy partners and the males fight over pebbles,
0:37:41 > 0:37:45to make sure they build them the biggest and finest nests.
0:37:49 > 0:37:51And they don't mind who gets in their way.
0:38:05 > 0:38:07A late arrival hurries into the colony.
0:38:15 > 0:38:19With the best nest sites taken, he is forced to the outskirts,
0:38:19 > 0:38:21where no-one wants to be.
0:38:23 > 0:38:26It's a cold and soggy place to build a love nest,
0:38:26 > 0:38:30especially when the point of the pebbles is to keep their eggs
0:38:30 > 0:38:31raised and dry.
0:38:34 > 0:38:37Spy Adelie helps as best he can...
0:38:38 > 0:38:40..with a well-placed pebble cam.
0:38:49 > 0:38:51But the latecomer isn't discouraged
0:38:51 > 0:38:54and gathers more pebbles, as fast as he can.
0:38:59 > 0:39:02But round here, you can't turn your back for a second.
0:39:02 > 0:39:05As soon as he puts it down, his pebble is stolen.
0:39:08 > 0:39:10The thief embellishes his impressive nest.
0:39:12 > 0:39:15Oblivious, the latecomer is travelling ever further
0:39:15 > 0:39:16to find stones...
0:39:20 > 0:39:22..while the crook takes advantage of the moment.
0:39:26 > 0:39:30He may have no moral code, but he certainly has a magnificent nest.
0:39:33 > 0:39:37In contrast, the latecomer's nest remains in a sorry state
0:39:37 > 0:39:41and the criminal penguin is getting ever more brazen...
0:39:41 > 0:39:42SQUAWKING
0:39:44 > 0:39:47..taking another trophy back to his ever-growing pile,
0:39:48 > 0:39:52..while the latecomer is becoming despondent.
0:39:55 > 0:39:56To make matters worse,
0:39:56 > 0:39:59the females have started to arrive.
0:40:05 > 0:40:08Females often remain faithful to their partners,
0:40:08 > 0:40:11but only if the nests meet their high expectations.
0:40:15 > 0:40:18So, for the latecomer, the pressure is on.
0:40:23 > 0:40:25She makes a considered inspection.
0:40:27 > 0:40:30Perhaps one last stone will swing it?
0:40:39 > 0:40:40He awaits her verdict.
0:40:47 > 0:40:50Her reaction is somewhat disappointing.
0:40:52 > 0:40:58Nearby, the bachelor thief proudly shows off his ill-gotten gains.
0:41:00 > 0:41:02There is only so much a female penguin can resist.
0:41:08 > 0:41:11She wants a male with a dry, raised nest,
0:41:11 > 0:41:13where her eggs will survive.
0:41:13 > 0:41:15And she's found one.
0:41:20 > 0:41:23But her jilted partner won't give up without a fight.
0:41:52 > 0:41:55It was a brave effort,
0:41:55 > 0:41:56but it wasn't enough.
0:41:58 > 0:42:01She chooses the thieving male with the finest nest.
0:42:03 > 0:42:05Her mate makes one last plea...
0:42:06 > 0:42:08..but it's all in vain...
0:42:11 > 0:42:15..and he's subjected to the final indignity.
0:42:30 > 0:42:35But Adelies are plucky and irrepressible birds
0:42:35 > 0:42:39and, if you can't beat them, join them.
0:42:40 > 0:42:43You can always build another nest,
0:42:43 > 0:42:46especially with a little help from a friend.
0:42:51 > 0:42:53Back in the warmth of Africa,
0:42:53 > 0:42:57spy tortoise is going undercover in more familiar territory.
0:43:00 > 0:43:02He's spending time with real tortoises,
0:43:02 > 0:43:06to record what insights into love they might offer.
0:43:07 > 0:43:11This leopard tortoise is desperately seeking a romantic liaison.
0:43:14 > 0:43:17As he sets off on this amorous quest,
0:43:17 > 0:43:19spy tortoise plays gooseberry.
0:43:28 > 0:43:31The hopeful suitor's technique lacks a certain subtlety.
0:43:38 > 0:43:40First, he gives chase.
0:43:51 > 0:43:53And then, a bit of a barge.
0:43:53 > 0:43:55CLUNKING
0:43:55 > 0:43:59If you're covered by a hard shell, it's difficult to be sensitive.
0:44:01 > 0:44:04And there's nothing subtle about what happens next.
0:44:23 > 0:44:26GASPING
0:44:32 > 0:44:35Spy tortoise is here to observe,
0:44:35 > 0:44:39but things don't always go to plan.
0:45:04 > 0:45:07Probably best to forget that ever happened.
0:45:11 > 0:45:12For our spy creatures,
0:45:12 > 0:45:16being immersed in the world of animals is not without its hazards.
0:45:22 > 0:45:24In Rajasthan,
0:45:24 > 0:45:28the temple languors have taken spy monkey into the heart of the family.
0:45:29 > 0:45:32But some are keen to take the budding relationship
0:45:32 > 0:45:33to the next level
0:45:33 > 0:45:35and are getting a little too familiar.
0:45:39 > 0:45:42One seems to want to babysit her.
0:45:47 > 0:45:48But disaster strikes.
0:45:50 > 0:45:53An injured baby is a cause for concern.
0:46:02 > 0:46:05And this languor seems to believe she's died.
0:46:08 > 0:46:11Then, something extraordinary happens.
0:46:19 > 0:46:22The monkeys gather round the motionless spy creature,
0:46:22 > 0:46:24as if it is a real baby.
0:46:47 > 0:46:51They react just as they do when their own babies die.
0:47:00 > 0:47:03A calm and contemplative mood descends on the colony.
0:47:06 > 0:47:10There's a sense of grief, as well as empathy for one another.
0:47:14 > 0:47:17Quite accidentally, our spy creature
0:47:17 > 0:47:22is at the centre of something extraordinary, capturing emotions
0:47:22 > 0:47:24that have rarely been observed.
0:47:34 > 0:47:39Such apparent expressions of grief may not be unique to primates.
0:47:48 > 0:47:50On the African savanna,
0:47:50 > 0:47:54spy tortoise is party to another unique event.
0:47:59 > 0:48:02Giraffes are appearing from every direction.
0:48:07 > 0:48:10This is what they've come to see.
0:48:15 > 0:48:17An old giraffe has passed away
0:48:17 > 0:48:20and it seems to have profoundly affected those
0:48:20 > 0:48:23who share these vast grasslands.
0:48:30 > 0:48:32And more keep arriving,
0:48:32 > 0:48:36creating an unprecedented assembly, never witnessed before.
0:49:06 > 0:49:09The giraffes kept arriving throughout the day,
0:49:09 > 0:49:13seemingly paying respects to the old male.
0:49:17 > 0:49:19An awareness of death
0:49:19 > 0:49:21was previously believed to have involved just a few
0:49:21 > 0:49:26highly intelligent species, but this seems to suggest otherwise.
0:49:44 > 0:49:49Such deep feelings are to be more expected among chimpanzees,
0:49:49 > 0:49:54but these intelligent animals still have the capacity to surprise.
0:49:56 > 0:49:58In the forests of Senegal,
0:49:58 > 0:50:01spy bushbaby is part of a team of spy cameras
0:50:01 > 0:50:05capturing intimate views of our closest living relatives.
0:50:18 > 0:50:21Here, the family lives a charmed existence.
0:50:28 > 0:50:33Parental love and friendships form the foundation of their society.
0:50:36 > 0:50:39Spy tortoise is also being deployed.
0:50:47 > 0:50:49But these are highly-perceptive animals...
0:51:03 > 0:51:06..and something's not quite right.
0:51:14 > 0:51:17This five-year-old checks what the others are thinking.
0:51:21 > 0:51:23They seem equally baffled.
0:51:31 > 0:51:35But with his curiosity piqued, he simply can't stay away.
0:51:50 > 0:51:55As his interest grows, so does the strength of his feelings.
0:51:55 > 0:51:57SCREECHING
0:52:00 > 0:52:05He just has to have spy tortoise all to himself.
0:52:22 > 0:52:26He hides with it in his leafy daybed,
0:52:26 > 0:52:27where he'd normally take a nap.
0:52:33 > 0:52:36But he's too excited to sleep.
0:52:43 > 0:52:47He's torn between using it as a pillow and giving it cuddle.
0:52:47 > 0:52:51It's somewhere between a toy and a pet.
0:53:00 > 0:53:04SCREECHING
0:53:14 > 0:53:16It's definitely not for sharing.
0:53:54 > 0:53:57Chimps don't normally have possessions,
0:53:57 > 0:54:00but spy tortoise has stirred new emotions.
0:54:06 > 0:54:08Elsewhere in the forest,
0:54:08 > 0:54:12spy bushbaby is helping document an equally-unique event.
0:54:21 > 0:54:25One of the older chimps is playing with a tiny kitten.
0:54:29 > 0:54:33It's the offspring of a genet cat found abandoned in the forest.
0:54:41 > 0:54:45He treats it with kid gloves, mindful not to hurt it.
0:54:50 > 0:54:52Even a nip is tolerated.
0:54:55 > 0:54:57The way he responds to the genet
0:54:57 > 0:55:01shows a very rare emotion in animals - empathy.
0:55:05 > 0:55:06Other chimps are intrigued.
0:55:20 > 0:55:23And one shows an unwelcome interest.
0:55:27 > 0:55:30This older chimp is used to having his own way,
0:55:30 > 0:55:34but without any feelings for the kitten, he's a bit too rough.
0:55:34 > 0:55:37The owner shows real concern and intervenes,
0:55:37 > 0:55:39to protect his vulnerable pet.
0:55:42 > 0:55:43And takes it from harm's way.
0:55:55 > 0:55:57They hide behind a termite mound.
0:55:58 > 0:56:03It's not just a private spot, it's also a chance for a snack.
0:56:08 > 0:56:11By using a stick, he can fish for termites.
0:56:17 > 0:56:19It's an intimate moment enjoyed with a special companion.
0:56:25 > 0:56:28Perhaps this is how human pet-keeping began.
0:56:33 > 0:56:36This is a glimpse of something quite remarkable -
0:56:36 > 0:56:40the first stirrings of empathy for another species.
0:56:46 > 0:56:48In the animal world,
0:56:48 > 0:56:50there are more ways of showing love and affection
0:56:50 > 0:56:53than we ever thought possible.
0:56:54 > 0:56:56From maternal devotion,
0:56:56 > 0:56:59to family affection.
0:56:59 > 0:57:00Through jealousy...
0:57:02 > 0:57:04..grief...
0:57:05 > 0:57:06..and romantic liaisons.
0:57:08 > 0:57:11These many incarnations of love in the animal world may offer
0:57:11 > 0:57:14a mirror to our own complex feelings.
0:57:15 > 0:57:18Next time, a team of new spy creatures
0:57:18 > 0:57:21film how intelligent animals really are,
0:57:21 > 0:57:24with some extraordinary revelations.