Scientists know very little about the manta’s life cycle, and the information presented here represents our best understanding pieced together from diverse reports, observations and theories
The largest recorded manta embryo had a wingspan of 1.27 m, and the smallest recorded free-swimming individuals are between 1.20 and 1.50 m. An average newborn has a wingspan of 1.10 – 1.30, and weighs around 11 kg (24 pounds). During the first year of their life, pups will double in size.
Mantas are thought to live in excess of 20 years, and maybe even as long as 100 years, but scientists do not yet know for sure.
The smallest recorded sexually mature females (confirmed by pregnancies in the field or by dissection) had a wingspan of 4.00 to 4.50 m, suggesting an age of about five to six years.
Sexual maturity for males appears to be six to eight years, based on the age at which claspers extend past the pelvic fins.
Adult females will produce a litter of one, or occasionally two pups, every one to three years. Females in some populations have been recorded to give birth annually, whereas in other populations pregnancies have not been recorded in consecutive years in any of the mature females.
Their low reproductive rate makes mantas extremely vulnerable to over fishing. However, life history information is limited, preventing an accurate assessment of the threat posed by fisheries.