Sir David Attenborough uses this episode to investigate two animals who are capable of true virgin birth - the production of offspring without the need for sex.

This episode explores the story of two animals that hide behind seemingly impregnable coat of arms. Can Sir David Attenborough get in behind their armour and reveal their mysteries?

Here we discover that some animals are able to trick others into believing they are something that they are not. The art of deception is a powerful attribute for some.

After initially gaining frightening reputations, it's now known that gorillas and bats are a lot gentler and considerate than their early reputations suggest.

Plants and animals have some curious super senses that enable them to see, hear and feel things that are quite invisible to us.

In this episode we explore the remarkable adaptations of two creatures that have evolved to survive the most challenging of conditions and seem to defy the laws of nature.

We'll find out how nature is incredibly inventive and has produced two unique mechanisms of natural construction that have fascinated scientists for centuries; weaving in birds and silk.

"Strange Parents" asks how we usually recognise animals as either male or female and how each sex normally plays a particular role in their own life cycle.

However both hyenas and seahorses completely break the gender rules.

"Magical Appearances" explores how swallows magically appear each spring and asks how did complex and beautiful insects like butterflies suddenly arrive in the summer.

The discovery of the swallow’s epic migration and the revelation that butterflies could metamorphose into totally different looking adults were scientific stories both cloaked in mystery and controversy.