Re: Do all mammals have the same number of vertebrae?

Do all mammals have the same number of vertebrae (backbones)?

No. 

Mammals typically range from 17 to 60+ vertebrae. Most of this variation is 
due to the tail. Tailbones are vertebrae, and mammals with long tails will 
have more vertebrae than do those with short, or no, tails.

You might have heard that all mammals have the same number of cervical 
(neck) vertebrae. This is almost true. Most mammals have seven cervical 
vertebrae. Only three types of mammals have a different number (the sloth, 
the manatee, and the spiny anteater).  So a giraffe, a human, a mouse, a 
whale, and just about any other mammal you can name, all have seven 
cervical vertebrae.