The females of Komodo dragons can give birth to baby lizards without previous contact with males. This kind of asexual reproduction is called parthenogenesis and has been observed in females kept in captivity without any relations with opposite sex individuals for years, if not for all their life.
Komodo dragons are huge monitor lizards – up to 3 meters
length- who live only in a few islands of central Indonesia. Most probably parthenogenesis
could be for them the only solution to continue the species under extreme
condition of isolation. In nature that can happen due to a storm which can lead
astray a single varanus while
swimming from island to island. Strong marine currents present in the area,
could also carry the dragon far away from its group to an unpopulated territory.
The reproduction without fertilization of the egg can give
birth only to male individuals because of genetic combinations. Females have
chromosome ZW and all the eggs carry one chromosome, W or Z. Their union will give
the male combination ZZ or WW. Eggs with the latter sequence are not going to
hatch. Certainly, this way of procreating is not very healthy for the species
being the genetic make-up derived only from one parent, but the offspring will
grow normally and will be able to mate.
Parthenogenesis is very rare in vertebrates, but has been observed
in snakes, fishes and even turkeys. Nevertheless, its discovery among Komodo dragons
has been the reason to reconsider it as “not so exceptional”.
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