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).
We estimate her wingspan at 16 feet. Big Bertha is a regular guest at the Manta Ray Experience and is comfortable with close encounters to divers and snorkelers. She can be seen at Manta Heaven and Manta Village. We have seen Big Big Bertha pregnant several times.