Animals with cloven hooves can fall ill

Professor David Waugh, Edinburgh Zoo's director, said: "If this carries on and we have to remain closed, then by the end of May we will be forced to rethink on how we can run Edinburgh Zoo in the future. This is very serious indeed."

As losses mount the animals still have to be fed and other running costs continue to increase up despite the lack of visitors.

The absence of the public has also affected the animals in an unexpected manner, according to headkeeper Darren McGarry.

He said he has been told by the monkey house keeper that the chimps are showing signs of missing the public attention they always attract.

He said: "She tells me the chimps are definitely missing the interaction from people coming into the house.

"She says that one of the female chimps sits and looks at the window every time she hears the door going, thinking it is some people coming in to see them."