To be fair to remoras, they do NOT suck blood! In fact, their sucker device is on the back of their head and is used only for holding on tightly to the host. Now maybe you can feel even better about being a remora--you simply want a free ride and to feed off of some scraps!

To be fair to remoras, they do not suck blood! In fact, they have what is considered a commensalism, not a parasitic, relationship with sharks. rollingharbour.com/.../wtf-whats-that-fish-remoras-weird-suckers/