Undecided questions
proverbs about animals

A dog is a man's best friend.
A bird in the hand is worth two in the bush.
A leopard cannot change its spots
Barking dogs seldom bite.
If you lay with dogs, you're gonna get fleas.
Let sleeping dogs lay.

"It's raining cats and dogs" - meaning its raining heavily.
"It's a dog eat dog world" - meaning the world is a harsh unforgiving place and people will take advantage of you at every opportunity (particularly used in business scenarios).
"The early bird catches the worm" - He/she who is "ahead of the game" or literally wakes up early is usually more successful or productive than others.
"I'm dog tired" - I'm very very tired!

Every dog has his day.
A cat has nine lives.
Every jack has his jill.