Here are some common animal idioms

Act as a guinea pig

When you act as a guinea pig, you allow some type of experiment to be done on you.

In many cases, the poor act as guinea pigs for clinical drug trials.

Ahead of the pack

When you are ahead of the pack, you are more successful than other people in your industry/profession. A pack is a group of wolves or dogs.

In the smartphone industry, Apple is ahead of the pack.

Alley cat

An alley cat is a stray cat.

As awkward as a cow on roller skates

When someone looks as awkward as a cow on roller skates, they look very awkward.

I was as awkward as a cow on roller skates, when I was first asked to give a public presentation.

As blind as a bat

When you are as blind as a bat, you are blind.

My grandfather is as blind as a bat. He can’t walk without help.

As busy as a beaver

When you are as busy as a beaver, you are very busy.

She was as busy as a beaver, so I decided not to disturb her.

As clean as a hound’s tooth

If something is as clean as a hound’s tooth, it is very clean.

She always keeps her home as clean as a hound’s tooth.

As conceited as a barber’s cat

If somebody is as conceited as a barber’s cat, they are very conceited or vain.

After winning the beauty pageant my friend has become as conceited as a barber’s cat.