They were broadcast on BBC Radio 4 in 2009 as part of the station's "Point of View" strand, in the weekly timeslot formerly occupied by Alistair Cooke's Letter from America.

[2] Speaking of his move from television to radio, Attenborough remarked that "It's a chance to talk about fossils, archaeopteryx" [3] and other subjects close to his heart, including his first pet, a salamander, and his favourite animal - the bird-of-paradise.

Gillian Reynolds, radio critic for The Daily Telegraph, wrote "his opening talk, about his affinity with the gently ruminant three-toed sloth, was pure delight".

She went on to describe Attenborough as a "gent, scholar, a brilliant communicator with a sense of humour", and added that "unlike many a radio broadcaster these days, he doesn't drop his voice on the key word in any sentence.

"[5] The Observer's Kate Kellaway, comparing the "Sloth" episode to Attenborough's television work, wrote "if the marvellous first programme is anything to go by, it will prove that we do not need to be on televisual safari to be completely intrigued.