Shortfin mako sharks, as with most other sharks, are aged by sectioning vertebrae — one of the few bony structures in sharks — and counting growth bands. The age of shortfin mako, and therefore important parameters, such as age at sexual maturity and longevity, were severely underestimated until 2006 (e.g. claims of sexual maturity at 4–6 years, claims of longevity as low as 11 years), because of a poorly supported belief that shortfin mako sharks deposited two growth bands per year in their vertebrae. This belief was overturned by a landmark study which proved that shortfin mako sharks only deposit one band in their vertebrae per year, as well as providing validated ages for numerous specimens.[27] Natanson et al.