Yes and no. If you want to do patent prosecution (applying for and getting patents issued while practicing before the USPTO), Then yes, you do. Kinda. You can also do your own classes etc up to a certain number of required credits to qualify for the patent bar. Here’s the info: http://www.uspto.gov/ip/boards/oed/exam/index.jsp
That said, if all you want to do it litigate patents (defend or prosecute infringement etc) you don’t NEED an engineering degree or to take the patent bar. BUT, many firms look for the science degree. With that training, you can talk the talk and be able to understand the patents and technologies you are working with. That also means the firm has to train you less.
SO, I would say that you don’t need it, but you really should get it. Biology is a good degree because you get exposure to all kinds of science across the board. That’s what i did.