Wildlife film-makers are to put the zzzzs into zoos with a BBC documentary devoted to watching animals sleep.
The 90-minute film spans 12 hours and will examine the patterns of behaviour as the various creatures rest during the hours of darkness.
The BBC4 programme, called Sleepover At The Zoo, is among more than 50 hours of newly commissioned natural history programmes to be screened by the corporation.
It has been largely filmed at Bristol Zoo with some newly shot scenes from other zoos. It will look at the impact of their natural environment on sleep patterns, whether the animals have pre-sleep rituals and whether they have nightmares.
Sleep patterns vary enormously with giraffes nodding off for just two hours at a time, while a slow loris can doze for 20 hours. Experts will track the sleep cycle hour-by-hour.
The new natural history programmes include a three-part series looking at extreme weather conditions, hosted by Richard Hammond, using cutting-edge techniques to capture footage. In Big Weather, he will watch a hailstone forming inside a cloud, go inside a firestorm and follow a tornado across a dusty plain.
A six-part BBC1 series Oceans will look at newly discovered species and use film technology which was not previously available for the BBC's last major underwater series Blue Planet in 2001.
And in The Hunt for BBC1, camera teams follow predators and their prey across the globe, watching polar bears stalk bearded seals, and golden eagles working together with wolves to capture mountain lambs in the Rocky mountains.
In another series Countdown To The Rains for BBC2, more than 75 cameras will capture the events as one of the most diverse areas of the planet prepares for the wet seasons along a one mile stretch of African river in the South Luangwa National Park.
Kim Shillinglaw, the BBC's head of natural history commissioning, said: "By using new filming techniques, peerless research and great storytelling, the next few years are all about shows that will delight our UK and global audiences.
"From new discoveries in Oceans and never-before filmed behaviour in The Hunt, to assembling 75 cameras in one place for Countdown To The Rains and the ground-breaking spirit of our night at the zoo event, we've never had as much range, scale and innovation to offer."