LONDON (REUTERS) - London Zoo began an annual weigh-in on Thursday (Aug 27) with keepers keen to find out what effect the zoo's longest closure since World War Two has had on its animals, having noticed some had suffered lockdown blues.

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.

"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.

"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."