Cameras held by elephants' trunks have been used to provide an intimate view of tigers in the jungle.
Because the big cats are used to the presence of elephants, the tusked giants were able to get far closer to them than a human film crew ever could.
Thanks to the "trunk-cams", the team was able to follow four newborn tiger cubs all the way through to adulthood.
The footage was recorded over a period of three years in the Pench National Park in India.
It is the basis of a three-part BBC One series: Tiger - Spy in the Jungle, which is narrated by Sir David Attenborough.
Series producer John Downer, from John Downer Productions, said: "Tigers are so secretive and they live in such dense jungle that it is very difficult for a human film crew to get close to them.
"But elephants are the ultimate four-by-four camera vehicle - and have allowed us to film these animals closer than we have ever been able to film them before."
The crew used three types of high-definition cameras, designed and built by Geoff Bell and operated by cameraman Michael Richards:
- A remotely-operated trunk-cam, which could film while the elephants were on the move and could also be set down.
- A remotely-operated tusk-cam, which was smaller than the trunk cam and could be carried by the elephants for much longer periods.
- Log and rock cams - cameras disguised as logs or rocks - which could be set down either by an elephant or human crew member and were activated by motion sensors.
Mr Downer said: "The elephants were remarkably stable - almost like a steady-cam, and they only needed a little bit of training to carry and set down the cameras.
"With these cameras, anywhere a tiger went or whatever it did, we could keep on filming it. They were the ultimate filming devices."
Mr Downer added: "This sort of thing hasn't been done before.
"It is a bit of a bonkers idea, and in my wildest dreams, when I thought about the challenges of filming tigers, I never thought we would suceed in doing what we did in this way, but now it seems the most natural thing in the world."
The cameras also recorded other animals, including langur monkeys, sloth bears and red dogs.
The first programme of Tiger- Spy in the Jungle will be shown on BBC One on Sunday 30 March at 2000 GMT