BBC Learning English - The Teacher

Funny video lessons

Bee

Bird

Cat

Dog

Fish
Horse

Insect

Monkey

Pig

Animate Your Idioms

Idioms with animated explanations, from the British Council website.

Second Nature Online English

Mini-lesson with definitions, examples and answers.

Idioms at English-at-Home

Long list of advanced-level idioms.

Animal Idioms

Quiz

UsingEnglish Idiom Dictionary - Animal Idioms

A huge number of idioms and definitions!