Zoo keepers Joe Capon (R) and Charli Ellis encourage a Galapagos giant tortoise to stand on weighing scales at ZSL London Zoo on Thursday. Reuters

Laura Garrett encourages meerkats with food to weighing scales at ZSL London Zoo. Reuters

The nearly 200-year-old zoo's finances have been savaged by the coronavirus that shuttered it till June, but its traditional week-long weigh-in will give staff a chance to see how its 19,000 animals have been faring.

Assistant Curator of Mammals, Teague Stubbington, said logging of sizes and weights, and in some cases pregnancies, was always important to the zoo for tracking species' health, but this time around it comes after a tricky period for some.

Mick Tiley records the weight of a Bactrian camel standing on the scales at ZSL London Zoo. Reuters

"The Pygmy goats were so used to seeing children during the day that (during lockdown) they would miss them," Stubbington told Reuters.

"They were actually lining up at the gate to meet people and then at 10 o'clock (when no one was there) they were disappointed," he added, saying that zoo staff would then try to cheer them up by going to see them during breaks.

Now open to limited numbers only, ZSL, the international conservation charity behind the zoo, is calling on the public to help it stay open by booking a ticket, joining as a member or make donations.

Martin Franklin weighs and counts humboldt penguins during the annual weigh-in at ZSL London Zoo. Reuters

"The loss of our visitors and the loss of income has made things really difficult," Stubbington said. "It has been the longest period of closure that we've had since World War Two."

Reuters