For more than 50 years, the name David Attenborough has been synonymous with the BBC's ground-breaking wildlife programmes.
Since he presented the first of his Zoo Quest series in 1954, he has delighted television viewers with his compelling commentary and insight into natural history.
But after a distinguished career, in which he has made pioneering films on almost every group of animals (remeber amazing mimic bird - Lyrebird?), Sir David, 81, looks likely to bow out next year with his series, Life In Cold Blood.
Shot in high definition at a cost of £800,000 per episode, the five-part series examines the world of reptiles and amphibians and marks the final chapter in Sir David's epic Life series.
It took two years to make in more than 20 countries, and used innovative filming methods to reveal that the creatures, far from being cold and slow, are in fact extremely dynamic.
Some of the techniques, including mounting tiny cameras on tortoise shells and sending microscopic lenses deep into underground lizard burrows, captured incredible moments.
Amazing firsts include wild rattlesnakes hunting, anacondas being born underwater, a male frog "giving birth", a mother caiman leading her crèche of babies to safety, and semaphoring Panamanian golden frogs.
In one scene, Sir David is filmed dangerously close to a spitting cobra whose venom, if it hits the naked eye, can permanently blind.
The broadcaster said his objective was to show the true nature of the animals.
"Reptiles and amphibians are sometimes thought of as slow, dim-witted and primitive," he said.
"In fact they can be lethally fast, spectacularly beautiful, surprisingly affectionate and extremely sophisticated."
Life in Cold Blood, which is due to be screened in February, comes 30 years after Sir David started his Life series with Life on Earth, watched by an estimated 500 million people.
At the time it was the most ambitious series produced and was followed by other classics including The Living Planet, The Life of Birds, The Life of Mammals and Life in the Freezer, a celebration of Antarctica.
The new series has been made by the BBC's renowned natural history unit, which is having £12 million taken from its £37 million budget, with 57 out of 180 posts being axed, as part of corporation-wide budget cuts.
Andrew Jackson, the managing director of Tigress Productions, an independent television company which makes wildlife shows, said the cuts were "short-sighted".
"The natural history unit is the leader in its field and what happens there has reverberations way beyond the BBC," he said.
"It's the depletion of the BBC talent base."
The BBC said the unit would continue to make landmark series.
Keith Scholey, the controller of factual production, said: "The natural history brand is probably the most important thing the BBC does and it has to be protected."
Other nature shows scheduled for next year include Pacific Abyss, in which a team of experts search for new marine species, Wild China, which focuses on the country's diverse landscapes, and Elephant Diaries, about a year in the life of orphaned baby elephants in Kenya.
By Nicole Martin