The hawksbill sea turtle, Eretmochelys imbricata is an exquisite small to medium-sized sea turtle characterized by an oval shell, a small elongated head and flippers with two claws. The elongated head tapers into a hooked jaw or beak-like structure. This is why this sea turtle is named the hawksbill sea turtle. This hooked shape enables the animal to reach into crevices of coral reefs and holes to find their favorite food: sponges. They grow up to a length that ranges from 0.62-1.14m in length and weigh typically around 80kg.
These turtles are unique and different from other sea turtles. They exhibit 5 distinguishing features, which include a head with two pairs of prefrontal scales, flippers with two claws each, thick overlapping scutes on the carapace, four pairs of costal scutes and a beak-shaped elongated mouth. The distinguishing overlapping scutes gives the creature its species name imbricata. Their scientific classification is as follows:
Distribution and Habitat
Hawksbill sea turtles are mostly associated with healthy coral reefs, however, they are observed to use several habitats at different stages of their life cycle. Juvenile turtles cannot dive into deep water, thus are found living on floating sea plants (sargassum). They then enter the water when they reach a carapace length of 20-25 cm. These turtles are found mainly in the tropical regions of the Pacific and Atlantic oceans. They are also found in the Indian Ocean and Oceanic Islands. They are migratory animals and are usually found in coral reef habitats featuring growing sponges. They are mostly found in shallow water (18.3 m or lesser) and find shelter in the ledges of reefs.
The top shell or carapace is thin and flexible comprising hard, bony plates called scutes. The carapace of an adult ranges from 63-90 cm in length and is brightly colored with elaborate patterns. The color of the carapace ranges from golden brown to dark brown and streaks of red, orange and black running down the shell. The scutes of the carapace are overlapping and is a distinguishing feature of this type of sea turtle. The carapace's rear edge is serrated except in the case of old sea turtles. It is the carapace that is sold widely as 'tortoiseshell'.
In Japan, the carapace was in great demand with the Japanese hawksbill shell trade touching around 30,000 kilograms of raw shells per year. However, in 1994, Japan stopped importing shells from other countries. The sale of tortoiseshell is illegal, however, it is sad to know that in 2006, processed shells were still being marketed in large amounts especially in Columbia and the Dominican Republic. The bottom shell is called plastron and is clear yellow in color. In hatchlings, the shells are 42 mm long and more or less heart-shaped and brown in color.
Favorite diet: Sponges
Hawksbill sea turtles are omnivorous, that is they can eat anything and everything. However, having said that, these turtles feed primarily on sponges. They also are very choosy! They consume only selected varieties of sponges, of which some sponges are toxic to other organisms. Besides sponges, they also feed on algae, mollusks, fish, sea anemones and the dangerous jellyfish, the Portuguese Man o' War. Shallow shoals abundant in brown algae are preferred feeding grounds by these animals.
The exact age at which these turtles reach sexual maturity is unknown. Every 2-3 years, mating takes place in shallow waters and copulation begins near the shore. The females leave the water during the breeding season and dig their nests in the sand (mostly near vegetation). The whole nesting process takes 1-3 hours comprising clearing the area, digging the pit, laying the eggs and then covering the pit with sand again. The females return to sea once the eggs are laid and buried.
Approximately 2 months later, tiny juvenile turtles are seen emerging at night. They find their way to the sea by a remarkable phenomenon. The light that is reflected off the water's surface from the moon's light guides them to their natural habitat: the sea. However, these days street lamps, building lights, car headlights are seen to misguide these tiny creatures. These infants start moving towards the light, away from the sea believing that the opposite side is their habitat. Their opposite movement leads them straight into the mouths of the predators. Further, if they are confused and remain stranded till the morning on the beach, then the morning sun is seen to burn them up. We humans have made life miserable for these creatures!
Hawksbill eggs were being eaten widely across the globe. Humans pounced on the turtle's egg and since these animals have a slow growth rate and low reproduction rate, their number has declined drastically. Sea turtles get entangled accidentally in fishing nets, thereby adding to the decline. Further, a destruction of natural habitat due to human interaction has caused these resplendent sea turtles to attain the international status of being critically endangered (1996-IUCN Red list). Despite the threat of their extinction, hawksbill turtles are being hunted for their flesh (delicacy) and glorious shells (decoration). Sale of turtle eggs and shells are illegal today.
These marine sea turtles play a significant role in the marine ecosystem. Their extinction will surely affect the ecosystem, which is why something must be done before it's too late. Smuggling and illegal sale of tortoiseshell is something that has to stop! These glorious creatures deserve to live!