As the documentary series following life at Chester Zoo returns, on Chimpanzee Island the younger males test the pecking order. And there's a fish out of water at the aquarium. Deer couple Serena and Odin welcome their second doe.

Hornbills survived a fire that swept through their home, but it may have derailed their plans for chicks. Meerkat matriarch Huskie seems to have lost her breeding instincts. Sun bear Milli has her paws full bringing up her daughter Kyra.

Adolescent babirusa Tolo has a hoof problem. Rock hyraxes Daissie and her partner Nungu are expecting their eighth litter. At the reptile house, the Bermuda skinks have a ferocious approach to mating as Poptart meets Sharkface.

Keepers are curious when Margery the Malayan tapir is suddenly eating for two; a deadly virus is suspected of being the cause behind a female hyacinth macaw's untimely death, her partner James Bond must undergo total isolation.

A couple of giant otters welcome four pups and must learn the difficulties of parenthood; a Red River hog struggles to survive alongside her two sisters; zookeepers try to help a sickly Batagur turtle that has them concerned.

The zookeepers run into obstacles as they try to transport an Asiatic lion king Iblis and his kin to a new habitat; a fight breaks out in the vampire crab exhibit; an Andean bear suffers from a broken heart and a toothache.

Zookeepers work through trouble as they try to pair Chester's newest bongo couple; a trio of silver-eared mesia chicks must find new shelter when a major storm destroys their nest; a Malagasy giant rat must undergo surgery.

A violent fight breaks out when a new chimpanzee attempts to overtake the current matriarch; the Zookeepers excitedly await confirmation that two Chinese croc lizards are expecting; two pink pigeons struggle to raise their young.

A sickly orangutan named Sarkiei mus be quarantined away from her prized son; when a mother giraffe named Dagmar becomes too thin, the zookeepers consider separating her from her calf; a male giant otter pup refuses to eat.

Rothschild's giraffes Mburo and Mojo miss out on their Christmas treat. Sparky is a new camel arrival. Mascara barb Clark has a date with three females named Kourtney, Kim and Khloe. Red panda Nina gives birth to twins Huey and Tiang.

The zoo's Sumatran orangutans are recovering from the horrific fire that engulfed their habitat in December 2018. Rothschild's giraffe Dagmar gives birth, but her calf struggles with its first steps.

Keepers spot that Asian short-clawed otter pups are developing bald patches, threatening their waterproofing. Plus, Caribbean flamingos, Asian elephants and dik-dik antelopes.

A pair of Bactrian camels experience the trauma of separation. Chester's Rothschild's giraffe herd expects another new arrival. Plus, spider monkeys and Cabot's tragopan pheasants.

Spotty chocolate poison dart frog Roy faces competition from hunky newcomer Hunter. And keepers hope there may be a first joey on the way for dusky padamelon Styx.

Keepers are keen to breed some baby eastern bongos, a critically-endangered species of antelope. Pinstripe damba fish George needs an immediate operation to prevent suffocation.

As the festive season approaches at Chester, the zoo's youngsters - from giraffes to monkeys - are about to have their first Christmas, and there are other newbies, too.

A pig goes on the run. Giraffe Narus is being moved to another zoo, but getting him into a horsebox isn't easy. And can the keepers encourage mono-browed fish Noel Gallagher and Frida Kahlo to mate?

Can adolescent orangutan Tuti prove that she's responsible enough to hold baby Kesuma? Dangerous turtle Shrek gets a new mate. Tiny babirusa piglet Tomini is struggling to survive. Plus: cheetahs.

Sloths Tina and Rico aren't getting on, and she won't ever let him get close to her. But Tina starts to put on weight. Is she pregnant? Or just eating too much? Plus: lions and monkeys and frogs.

When dik dik Kahri becomes a dad, his fight or flight instinct goes into overdrive. Meanwhile, the keepers face the dangerous task of replacing a broken window in the reticulated python habitat.

Andean bears Lima and Madidi aren't getting on. Giant otter couple Diego and Icana have never mated; can new male Tarubu relight Icana's fire? And two butterflies get drunk on fermented fruit.

Flamingo mum Calypso loses interest in mothering her chick, Marley. Three of the zoo's rare onagers are pregnant at the same time. And a baby macaque gets picked on by some older females.

Jaguars Napo and Goshi haven't been breeding. Will training Napo to be more assertive change that? Young elephants Aayu and Nandita are seriously ill. Plus: silvery gibbons and dragon-headed katydids.

This deep-dive special episode explores the extraordinary underwater world of Chester Zoo, featuring blind fish, rare amphibians and a frisky penguin

The keepers think that pregnant elephant Thi is three months overdue. Rampant giraffe Meru relentlessly chases the females in his herd. Plus: anteaters and clownfish.

Chimp Zee Zee gives birth to a daughter. Elderly chameleon Mr Parsons has a date. And Gaston the banteng bull has made three females in his herd pregnant.

Young tapir Solo is moving to a new zoo. Pregnant rhino Asha goes into labour at night. Mantis Minnie is looking for a sexual partner, but female mantises have a bad habit of eating their partners.

Young meerkats Beagle and Huskie become parents for the first time. And can painted dog Ville look after his seven adolescent pups on his own while the vets check up on their mum?

Bush dog Mana is pregnant. There's a power struggle on chimp island. Otter Wallace is struck down by a mystery illness. And is romance in the air for wattled cranes Wilma and Ivan?

Red panda Nima's new mate, Koda, chases her up a tree. Baby meerkat Junior is struggling to get enough food. And a shy penguin isn't socialising with his colony.

Tortoises Burt and Terrance, who've been best mates for 70 years, compete for the affections of breeding female Smooth Sides. Pregnant okapi K'Tusha is due to give birth. Plus: vultures and elephants.

It's Christmas at Chester Zoo. The UK's first ever surviving sun bear cub is born, and there's a yuletide ceasefire in the turf war between the otters and the babirusas.

Chameleons Charles and Eddie try to impress new arrival Ruby. Orangutan sisters Emma and Subis are expecting babies by male Puluh at the same time. The aardvarks are making the new meerkats anxious.

African painted dog K'mana is pregnant with Chester's first ever litter of this endangered species. Meanwhile, can atlas moths Dave and Simon find mates during their five-day lifespan? Plus: okapis.

Giraffe Orla is due to give birth. Orangutan baby Tombol tests his luck with the gibbons. Overconfident ibis chick Professor X gets into trouble. Can a timid sengi take over his dad's breeding duties?

Young orangutan Tripa is half the size of other orangutans his age. He relies on his mum for everything but can he become independent when she has a new baby? Plus: penguins, beetles and painted dogs.

Spider monkey Kiara seems more interested in hanging out with the youngsters than looking after her baby. Baby capybara Henry enjoys having the attention of all the female capybaras.

The keepers struggle to transport a suspicious warthog and a giraffe. Caiman lizard Gary keeps diving into the pool headfirst, even when it's empty. A baby gibbon is a passion killer for its parents.

Four rare and mysterious tenrecs arrive at the zoo. Endangered eastern black rhino Kitani is due to give birth. And jewel wasp Ripley searches for a cockroach to turn into a zombie egg incubator.

Red panda Jung is losing weight and no one knows why. Mandrill Ludo gets over-friendly with his dad's girlfriend when his dad's at the vet's. Plus: tigers, and penguins.

Pygmy marmoset Audrey has to carry her babies everywhere. Andean bear cub Madidi embarks on an adventure into a neighbouring paddock. Plus: young elephants and baby hyraxes.

The chimps have been brandishing a large stick; keeper Niall tries to get it back. Male onager Holmes chases every female in sight - including the camel next door - during mating season.

Chester's bachelor pad of lemurs is about to be in for a shock with a dominant female on her way; a novice zebra starts to make a play for power, which isn't to top zebra Florence's liking; the keepers are desperate to breed Javan green magpies.

The keepers are busy making gifts for the animals but there's chaos when the chimps seek out their parcels. Will dwarf mongooses Cooper and Mini have new babies before Christmas? Plus rhinos and ants.

Sloth Tina has been giving her partner Rico a hard time, but the keepers have a plan to bring them closer together. And three-legged chameleon Tripod goes speed-dating.

The tapirs move to a new home. Golden poison frog Pablo has lost interest in his partner Maria, so bad boy El Loco is brought in to shake things up. Baby porcupine Marion faces off the meerkat mob.

Sun bears Toni and Millie have relationship problems. Critically endangered eastern black rhino Zuri gives birth to baby Ike. Otter Annie has three new pups. And camel Shan-shan is unwell.

It is time for mouse deer Una to leave her parents and meet a mate of her own, but she is being shy around her future partner, Biani. Aardvark Koos gets romantic with his sister in this night-time special. Can underdog seahorse Seabiscuit grow the vital appendage he needs to attract a mate?

Can mantis Bruce survive mating with deadly Natasha? Rhino couple Beni and Asha are reunited after four years apart. Giant anteater Pedro falls ill. Bald ibis chick Britney is critically underweight.

Young giraffe mum Tula gives birth, while this year's brood of penguin chicks face the ordeal of joining the main pool, where they must compete for fish with the adult penguins

The arrival of a new female chimp causes upheaval at the zoo, baby otter Bo goes missing, cheetah mum Kinky Tail is on the operating table, and the meerkats steal the porcupines' food

Young elephant Nandita isn't happy when her half-sister is born. Bush dog Franco has got his sister-in-law pregnant. Rhino beetle Sheldon has a damaged wing case; can he impress female beetle Alice?

Tapir Jenny, who has two young offspring, falls ill. Can rhino Kifaru, who has arthritic knees, mate with younger, taller and heavier female rhino Malindi? Widowed porcupine Roxy meets a new mate.

Rare okapi Stomp injures K'Tusha with his horn when he tries to mate with her. Two African painted dogs compete to impress two new females. Plus: turtles and cassowaries.

Mr Parsons the chameleon meets a new mate, Daphne from Paris. Young giraffe Murchison faces the great outdoors for the first time. And another baby elephant is born.

Two of Chester Zoo's zebras are about to give birth. Meanwhile, lioness Kumari seems to be losing interest in her partner, Iblis. And two of warthog Magnum's children are becoming hard to control.

Kendari the babirusa is pregnant, but otters Wallace and Annie keep throwing stones at her house. Next door, orangutan Willie is struggling to impress females Sarikei and Leia.

Penguin chick Munch fights for his life when there's disease in the colony. When young male tortoise Football muscles in on 71-year-old Bert's harem, the keepers bring in two Swedish female tortoises.

Oana the anoa and capybara Lochley both give birth. Tiger mum Kirana's sons are being moved to other zoos to start their own families. Young monkey Rocky won't pay attention to his mum's life lessons.

Four of Chester's orangutans go missing. The dominant female meerkat faces a power struggle with her own daughter. Can bull elephant Aung Bo help provide a baby to keep lone youngster Nandita company?

Grumpy elephant Thi is expecting a baby. The chimps battle for dominance. Red panda Nima gives her partner Jung the cold shoulder. And the meerkats prove they're not as loveable as they first seem.

Inseparable penguins Rud and Spike have been a couple for 15 years. But Rud's arthritic hip could be affecting his quality of life. The tigers move house, and a tarantula risks his life to reproduce.

The giraffe family have a new arrival. Frog keeper Pip creates a love den to try to get endangered frogs in the mood to lay eggs. And the aardvarks wreak havoc by night.

A potentially deadly virus hits the elephant house. Will Chester's female zebras be interested in new stallion Mac? Plus: the bizarre world of the naked mole rat.

Boris the chimp takes a moorhen chick hostage. French crocodile François turns his snout up at British food. The keepers try to spark romance between turtles Raja and Aris. Plus: young penguins.

Female rhino Kitani is introduced to her new mate, Magadi. But rhino mating is a risky business. There's a surprise birth in the orangutan house. Plus: fruit bats, macaques and young jaguars.

Young orangutan Indah decides to open all of her family's Christmas stockings. There's a Christmas baby in the tapir house. Ten brave keepers have to catch reticulated python Bali for a health check.

This deep-dive special episode explores the extraordinary underwater world of Chester Zoo, featuring blind fish, rare amphibians and a frisky penguin

A look back at the most extraordinary births caught on camera at Chester Zoo., including a pregnant elephant and a wasp seeking a cockroach for a mate to paralyze with venom.

Some of Chester Zoo's animals are happily together forever, including penguins Rudd and Spike, and sloths Tina and Rico, who spend up to 18 hours a day fast asleep.

A look back at some of Chester Zoo's expert escapologists, from Sumatran orangutans to blue-throated macaws and an Andean bear cub on the adventure of a lifetime.

Pedro the giant anteater falls ill and faces a major operation. Chester Zoo's rare bald ibises produce a batch of new chicks. And a rhino couple are reunited after four years apart.