Blake and Bella have been missing since last week.
The mystery surrounding the disappearance of Blake the dog and Bella the lamb deepened last night as a heat-seeking drone failed to spot signs of the unlikely animal friends.
Britain is desperate for news of the sheepdog and lamb, who ran off together on Monday last week.
Just as the hunt for the Tamworth Two - pigs that escaped an abattoir - caught Britons' imaginations in 1998, the hunt for the 1-year-old border collie cross and 5-week-old lamb has sparked a similar response.
Although hoof and paw prints, as well as animal droppings, have been found, there have been no positive sightings.
Blake and Bella disappeared from owner Natalie Haywood's garden and since then volunteers, park rangers and even professional pet detectives with sniffer dogs have been hunting for them.
Posters have been plastered on trees near Miss Haywood's home, in the village of Perlethorpe, Nottinghamshire, and thousands have shared details of the missing pets via social media.
Ah so cute. "Inseparable" Bella and Blake before they went missing. A £1,000 reward has been offered in the search for the orphaned lamb and sheepdog. http://bbc.in/2qw8iW2
Even television presenter Phillip Schofield pledged a £1000 ($1900) reward to anyone who finds the pair following an appeal live on breakfast TV. In a bid to entice them home, Haywood and her partner mechanic Jordan Knight, 22, also held a barbecue and camped out with friends on Saturday evening, hoping Blake would be attracted to the smell of sausages.
The couple, who have two young children, have also continued to lay out Bella's favourite food, Cheerios, alongside chicken scraps for Blake, in their porch every day. Neither strategy has worked.
On Saturday, the Daily Mail sent up a drone with thermal imaging cameras to scour the dense woodland of Sherwood Forest and the Thoresby estate, Nottinghamshire, where experts believe the pair could be hiding. It was sent on 15 separate 10-minute flights buzzing at 400ft over several square kilometres. Although it failed to spot the pair, sniffer dogs picked up a fresh scent and more hoof and paw prints were discovered.
Knight said: 'It's a shame that the drone didn't pick anything up, but it's a large area. It was a long shot. The guy gave it a good go - he was out there for about seven hours. I'm more positive about the fact that we found fresh paw and hoof prints, which show that they are still on the move. We are staying optimistic.'
Blake and Bella have been inseparable since Haywood adopted the lamb when she was rejected by her mother at two days' old.
Despite the lack of sightings, Haywood remains upbeat. However yesterday she admitted: 'We're all absolutely exhausted.
'We haven't really slept since Thursday. The sniffer dogs have worked well and we've set up some scent trails with chicken and water from where Blake was last scented. Our friend has also got motion cameras set up.'
Pet detective and wildlife warden Phoebe Cooper, 73, whose 10-year-old dog Wispa, a German pointer-lurcher cross, has been helping with the search, said a 'resourceful' dogs can survive for months in such circumstances.
'It's very much a waiting game, it can take months,' she said.