From Paignton's local paper today:
HOW do you know if an orangutan is pregnant?
It is a question puzzling keepers at Paignton Zoo as they 'watch and wait' to see if three female Bornean orangutans are definitely with child.
In early December the zoo announced all three were thought to be pregnant, with births expected within a couple of months.
But since then, pregnancy tests designed for humans have proved negative.
However some behaviour patterns still point that multiple births could be around the corner. A zoo spokesman said: "We can't take it to see a gynaecologist and using pregnancy testing kits designed for humans is not always reliable, so in the end all we can do is watch and wait."
Keepers believe a change in the orangs' behaviour is the key as the foursome are no longer sexually active.
Neil Bemment, curator of mammals and the man with the most orang experience at the zoo, said: "This is when regular keeper observations are so important.
"They see their animals every day, they know their routines and their behaviour, they know when these routines or behaviour change.
"The strongest evidence for the three being pregnant is that they do not appear to have come back into season and the male shows no signs of mating them now.
"If we go by the last observed mating between Demo and Mali then she would be four weeks overdue now, but we may well have missed a mating a month later. This would account for the delay.
"Orangs can give birth with very little warning. It can vary from individual to individual, but there may be very few behavioural changes."
The zoo's group of Bornean orangutans is made up of male Demo, 10, and females Gambira,11, Chinta, 18, and Mali, 13.
Vet Sarah Hewitt said: "We tried testing with human pregnancy testing kits, but these came out negative."
She said the kits can be accurate in the early stages of an orang pregnancy but they become less reliable later on.
"We can perform blood tests or ultrasound scans to confirm pregnancy. Animals can be trained to come to the safety barriers in the off-show areas so that vets can take blood samples or even do scans.
"Our female orangs are not trained to do this, so it's not an option now, though it's something I'd like to look at for the future.
"To do a scan in these individuals we would have to use a general anaesthetic, but that's something we don't want to be doing at a critical time like this unless we really have to."