Nature can baffle us so much we don't believe what we see. In these two stories David Attenborough discovers the curiosities that have led to accusations of forgery and have ultimately helped us rethink evolution.

Encoded with permission for digital streaming by Infobase on November 24, 2014. Learn360 is distributed by Infobase for Films for the Humanities & Sciences, Cambridge Educational, Meridian Education, and Shopware.

The Platypus(4:08) -- Is the Platypus a Mammal? (2:23) -- Does the Platypus Lay Eggs? (3:41) -- The Midwife Toad (4:37) -- Environmental Influences on Bodily Changes (2:28) -- An Unresolved Theory (3:40) -- Credits: A Curious Hoax? Attenborough's Natural Curiosities, Series 1 (0:44).