The movement of the hard drive's read/write heads over different areas of the disk when accessing fragmented files is slower, compared to accessing the entire contents of a non-fragmented file sequentially without moving the read/write heads to seek other fragments.
The dorsal fins are small and at the base of the tail. The largest mantas can reach 1,350 kg (2,980 lb). In both species the width is approximately 2.2 times the length of the body; M. birostris reaches at least 7 m (23 ft) in width while M. alfredi reaches about 5.5 m (18 ft).
Humans are the biggest predators of the Manta Ray. In many parts of the world hunting for them continues to be a huge industry. This includes areas of Mexico, California, and Australia.Manta Rays are hunted for their meat, for their skin that feels like sandpaper, and for their oil.