Round Island Boa, Casarea dussumeiri

The Round Island Boa (Casarea dussumeiri) may sometimes be referred to as the Round Island Keel-scaled Boa. It is ranked as one of the world’s most endangered species and it is estimated there are fewer than 1000 left in the wild.

In the mid-1800s, the Round Island Boa became restricted to Round Island due to the invasion of predatory rats in the surrounding regions. The species remains exclusive to the Indian Ocean to this day.

Throughout the years the habitat of the Round Island Boa has been interrupted by the introduction of goats, rabbits, rats and other environmental factors. In recent years, there has been a lot of work dedicated to the removal of destructive factors. Continual breeding and relocation efforts have also been crucial in ensuring the species’ survival.

Its slim body is covered in small keel scales and can grow as long as 5 ft. The Round Island Boa’s skin cells contain several colors creating the ability to shift in colors throughout the day. They are known to shift from dark to light depending on its activity and time of day.

Typically boas are known to give birth to live young, however, The Round Island Boa lays eggs. After an unusually long incubation period of 90 days, the young hatch weighing less than 2 ounces and are bright orange in color.

Round Island Boas are equipped with an especially unique upper jaw. The maxilla (upper jaw) consists of bones that are divided into movable front and back parts, a helpful adaptation for catching hard-bodied or barrel-shaped prey.  One part hinges the boa’s jaw, allowing it to open and close its mouth, while the other part allows the top jaw to hinge downwards.

Image Caption: Round Island Boa north of Mauritius. Credit: Jjargoud/Wikipedia (CC BY-SA 3.0, 2.5, 2.0 and 1.0)