But instead, the monkeys' pranks are unobserved, King Cobra is coiled friendless in the reptile house and the future of the world's oldest scientific zoo is in peril.
As the menagerie in Regent's Park, central London, nurses a multi-million-pound hole in its budget and lockdown keeps visitors away, even during school holidays, the keepers are sad and anxious.
"We are losing so much money," said Sanders. "I'm concerned the zoo might not survive."
Opened in 1828 by the Zoological Society of London (ZSL), London Zoo was visited by Charles Darwin while he was writing his "Origin of Species" and Queen Elizabeth II is its patron.
Feeding them costs around 1 million pounds ($1.4 million) a month and the latest lockdown will blow a 1.8 million pound hole in its budget on top of the 15 million pound loss last year.
"It just remains so sad that we are closed," ZSL London Zoo’s Chief Operating Officer Kathryn England said. "We can't furlough animals and you can't furlough all of the staff who look after the animals."
"More importantly, we are here to inspire people about wildlife and as long as we are closed, we have to find very ingenious ways of doing that," she said. "But nothing really beats having people in the zoo and having a great day out."
"It's hard - it's really hard."