Woolly monkey Oaska unfortunately passes away. Suffering from severe spinal arthritis, his condition rapidly worsens, leading the primate care team to make the tough decision to euthanise him.
There's two new arrivals at the park a baby woolly monkey for experienced mum Xingu, and dad Oaska and Alison's been to Wales to collect a new squirrel monkey called Azzi who was being kept as a pet.
Alison calls in a specialist eye surgeon to perform the cataract operation on Lola the chimpanzee, Mr Bray normally operates on humans so it's a unique experience for man and ape only time will tell if the operation has been successful.
Ruby, the park's newest and largest marmoset, is introduced to males Jock and Colin, but the introduction does not go as planned the primate care team observes that Lola, a chimpanzee in Paddy's group, experiences vision problems.
It's graduation day as baby golden-cheeked gibbon Mikado moves in with his new foster mum Alex, full time, and geriatric stumpie Gerald is rushed to the operating theatre.
The staff prepares for two new woolly monkeys from Switzerland, and the male capuchins are put to the test with a clever puzzle feeder.
Staff are anxious as chimp Athena undergoes an eye operation and woolly monkey Piquita's baby is finally given a name.
It's a big day for baby golden-cheeked gibbon Mikado as he's introduced to his new foster mum Alex, and Gordon's orang-utan group have a bit of fun with some colourful balls.
Tensions are high as popular chimp, Sammy, goes under the knife, and the stump-tailed macaque house gets a makeover to accommodate its elderly ugly monkeys.
It's handbags at dawn in the orang-utan nursery as new arrival Oshine meets foster mum A-mei. Piquita becomes a new mum, and Mikado settles in after his first week at the park.
Mike has a tricky time collecting a baby gibbon from France. Meanwhile, at Monkey World, the chimps have fun with fabric, and squirrel monkey Fidget settles into his new home.
Oshine has an eventful first night in the orang-utan nursery and there is exciting news for the woolly monkeys. Plus, Hananya's gang go wild over the revamped chimp enclosure.
There's a problem at the airport with the transportation of overweight orang-utan Oshine from South Africa - will she make it onto the plane?
The team wants to bring a seriously overweight orang-utan to the UK, but it is harder than they hoped, and back at Monkey World the Bachelor boys celebrate a bedding bonanza.
Paddy's chimps go mad for mangoes and rumours abound of a weighty new arrival from South Africa. Plus, Alison saves an old pet squirrel monkey that desperately needs a new home.
Disturbing footage convinces Alison to rescue an adult female chimpanzee working in the tourist industry in Mexico, who urgently needs the team's help. The nursery chimps have a play session.
Jonathan is over groomed and has gone bald, while Tom, one of the alpha male capuchins, has died. Elsewhere, the chimps are given walnuts and Jestah gets more than his fair share.
A baby chimp tries to prove he is grown up enough to go it alone. The Bachelor Boys' reputation, meanwhile, takes a hit when they become frightened of a new toy.
A big decision must be made when alpha male Hananya continues to exhibit violent behaviour. Chimps Simon and Eveline, meanwhile, compete in a swing-off and there is some dental surgery to be done.
Resident capuchin TJ joins the new Chile arrivals, but he seems to be in a mischievous mood, and Alpha male chimp Paddy has to step in and keep his unruly troop in line. Elsewhere, orangutan Amy is pregnant.