In each sentence, an animal is concealed. Can you find the Them?

In each sentence, an animal is concealed.

The first sentence has dog concealed.

Can you find the others?

01. What shall I do, Gertrude?

02. Asking nutty questions can be most annoying.

03. A gold key is not a common key.

04. Horace tries in school to be a very good boy.

05. People who drive too fast are likely to be arrested.

06. Did I ever tell you, Bill, I once found a dollar?

07. John came late to his arithmetic class.

08. I enjoy listening to music at night.