Anna, a female green anaconda that has lived most of her life in an all-female enclosure at the New England Aquarium, has given birth.

The anaconda produced 18 snakes in early January. A DNA test has confirmed that the births were a result of a nonsexual reproduction process known as parthenogenesis, or "virgin birth," according to the aquarium.

Parthenogenesis commonly occurs in the plant world and among animals without a backbone, but is rare among vertebrates. The process has been documented only among lizards, birds, sharks and snakes.

The phenomenon involving Anna is the second known confirmed case of parthenogenesis for a green anaconda. The first was at a British zoo in 2014.

Only two of Anna's 18 offspring have survived.

Aquarium staff said the young snakes are clones of their mother. Limited genetic sequencing shows complete matches on all the sites tested. (VOA)