The great white shark is very well known for its size, with the  largest individuals known to have approached or exceeded 6 metres  (20 ft) in length and 2,268 kilograms (5,000 lb) in weight. It  reaches maturity at around 15 years of age and can have a life span  of over 30 years.
Benign fasciculation syndrome is characterized by occasional or nearly continuous twitching of various skeletal (voluntary) muscles in the body. This type of muscle twitching can also be seen in association with serious disorders like spinal injury, multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS).
Amyotrophic lateral sclerosis. Amyotrophic lateral sclerosis, or ALS, is a disease of the nerve cells in the brain and spinal cord that control voluntary muscle movement. ALS is also known as Lou Gehrig's disease. 1 out of 10 cases of ALS are due to a genetic defect. The cause is unknown in most other cases. In ALS, motor nerve cells (neurons) waste away or die, and can no longer send messages to muscles. This eventually leads to muscle weakening, twitching, and an inability to move the arms, legs, and body.