' Egg ##ed lizards ' preserved in captivity for 75 + years were studied . hundreds of Alberta experts said differences in size and shape of tail bones enable male and female small feathered tails to be sexed . Males have long ' chevron ' bones so they can wiggle their feathered tails seductively to woo mates , while females have shorter bones in their tails .
'Egg thief lizards ' preserved in rock for 75 million years were studied . University of Alberta experts said differences in size and shape of tail bones enable male and female small feathered dinosaurs to be sexed . Males have long 'chevron ' bones so they can wiggle their feathered tails seductively to woo mates , while females have shorter bones in their tails .