What are two disadvantages of cephalization?

1. The animal can't see what happening behind its head.

2. Head can be moved upto 180 degree angle in most of the animals including humans. But it is not true in case of birds.

1) Since all the important tissues like the sensory and nervous tissues have been concentrated on the head, a damage to the head will lead to a damage to important organs.

2) The animal would not be able to see activities taking place behind the head.