The Bluespotted Ribbontail Ray is a common sight at dive sites around Koh Tao. During the day, they often rest in small overhangs, but come evening, they venture out to explore and hunt.
Distinguishing Features
The Bluespotted Ribbontail Ray (Taeniura lymma) is a species of stingray in the family Dasyatidae, easily recognized by its vibrant color pattern. Its body is elongated and oval-shaped, with electric blue spots on a background that ranges from yellow to brown to olive-green, and a pair of blue stripes on the tail. The ray’s bright yellow eyes protrude from its body, and it can adjust the size of its pupils.
Located on the underside of the body are the mouth and gills. The mouth contains two hard plates used to crush the shells of crabs, prawns, and mollusks. Bluespotted Ribbontail Rays typically grow to about 35 cm in width and can reach lengths of up to 80 cm, weighing no more than 5 kg. Each ray has a unique pattern of blue spots, making every individual distinct.
Behavior
- Bluespotted Ribbontail Rays are generally solitary and spend most of their time resting on the ocean floor. They are known for their shy and elusive nature, often hiding in sand or coral to avoid predators. During the day, they typically stay hidden, becoming more active at night when they hunt for food. Their diet mainly consists of small fish, crustaceans, and mollusks.
- Alongside their eyes, Bluespotted Ribbontail Rays have two spiracles. These are small openings used to draw water into their gill chamber, allowing them to push water over their gills for breathing while they rest on the ocean floor.
- Bluespotted Ribbontail Rays glide effortlessly through the water with their pectoral fins. They use electroreception to hunt, detecting prey hidden in the sand by picking up on tiny electrical fields and temperature changes. This ability helps them find their next meal with precision. While hunting, they stir up the sand with their snout to uncover concealed prey. Electroreception also aids in communication with other rays and helps them navigate their surroundings.
- Unlike other stingray species, Bluespotted Ribbontail Rays rarely bury themselves completely. Instead, they keep their bright blue spots visible to warn potential predators of their venomous tail spines. They have no teeth; instead, they crush their prey between two hard tooth plates in their mouth, effectively handling and consuming their marine meals.
Breeding
The Bluespotted Ribbontail Ray is ovoviviparous, meaning the embryos develop inside the mother, nourished by yolk, and hatch internally. Each litter consists of about seven live young, all with their distinctive blue markings.
During courtship, the male uses his sensitive nose to detect chemical signals from the female, often nibbling or biting her disc. He fertilizes her internally using his claspers. Breeding usually happens from late spring to summer, with gestation lasting between four months and a year. At birth, the young rays are about nine cm long and emerge from egg cases with a soft, protective tail. This tail’s thin layer of skin protects the mother during delivery and eventually sheds, becoming an important defense mechanism for the newborn rays.
Predators
The main predators of Bluespotted Ribbontail Rays are humans and hammerhead sharks. Humans often keep them in aquariums, though they are challenging to care for. Hammerhead sharks, on the other hand, use the cartilaginous projections on their heads to pin the stingray to the substrate, allowing them to bite the ray's disc while avoiding the venomous tail spines.
Where to Find Bluespotted stingray on Koh Tao
The Bluespotted Ribbontail Ray is a bottom-dwelling species that typically resides on coral reefs and nearby sandy flats. You can spot this ray at several dive sites around Koh Tao, including:
White Rock,
Twin Peaks,
Tanote Bay,
Japanese Garden,
Aow Leuk,
Mango Bay,
(etc)
Diving in Koh Tao offers numerous opportunities to encounter Bluespotted Ribbontail Rays.
