LONDON (Reuters) - The world’s oldest zoo is shut to the public for the first time since World War Two as London locks down because of the coronavirus pandemic, but for the roughly 18,000 animals housed there, life must go on.

London Zoo, opened to scientists in 1828 and to the public in 1847, is one of the British capital’s most-loved attractions, but like everything else in the city it has been impacted by the ongoing crisis, raising concern about the animals’ welfare.

Unlike a museum or an art gallery, it is not just a case of locking the doors.

Captive animals are needy, whether big beasts such as lions, gorillas, zebras and giraffes or the Madagascan hissing cockroaches, or everything else in between.

It is a costly, and labor-intensive, business, and without the revenue from daily tickets sales -- worth 27.8 million pounds ($33 million) last year from London Zoo and ZSL’s Whipsnade Zoo -- a prolonged shutdown is a nightmare scenario.

Add in the logistical problems posed for the small army of zookeepers, vets, security and ground staff (none classified as key workers) in getting to the Regents Park site, if they have not been forced to self-isolate, and it is unsurprising London Zoo is appealing for donations.

“Ordinarily, we are entirely reliant on public support, so without people coming through the gates the income isn’t coming in,” ZSL’s chief operating officer, Kathryn England, told Reuters on Wednesday. “We are really having to find other ways for people to show their support for us and donate instead.

FILE PHOTO: Bhanu the lion is seen during the annual stocktake at ZSL London Zoo in London, Britain, January 2, 2020. REUTERS/Henry Nicholls

“What is important is that we have been planning for this, so that we can make sure our staff can keep coming in and putting the health and welfare of our animals first,” she said. “Our animals eat a lot and we have to make sure our supply chains continue, with top-quality food. Whether that’s fruit and veg from Covent Garden, or meat, we need a continuous supply.”

To ensure they can get to work, many of the zoo’s 50 daily staff have opted to live in the zoo’s Lion Lodges that usually house overnight guests experiencing a “zoo sleepover”.

“They are not classified as key workers but they are absolutely essential to us,” England said.

“They are a team of astonishingly dedicated staff,” she said. “Some are staying on site to make sure the animals get the care they need. We need to make sure we have all the staff in.”

To safeguard the health of the animals, zookeepers wear protective clothing, such as face masks and gloves.

With no crowds wandering around, some might suggest the animals will be enjoying some rare peace and quiet. But that also brings challenges.

“The zookeepers are not only feeding them, mucking them out but also providing the enrichment that they need as well because this is very different environment that they’re in with no visitors,” England said.

“The big cats don’t seem to be bothered at all, like Bhanu our big lion. He’s just lounging around in the sun. But the pigmy goats and penguins are a bit confused.”

While England is confident the shutdown will not endanger any of the animals, she said the loss of revenue was one of the biggest challengers the zoo has faced.

“The (public’s) response has been overwhelming so far, but we are a charity and in a good year we would have 1 million people coming through the gates.

"We are really missing the crowds and we really want people to support us through our website www.zsl.org/zsl-london-zoo."