page_title: Round ribbontail ray
section_title: Biology and ecology
hierarchical_section_title: Round ribbontail ray / Biology and ecology
caption_attribution_description: Blotched fantail ray (Taeniura meyeni) at the Great Barrier Reef, Cairns, Australia
context_page_description: The round ribbontail ray is a species of stingray in the family Dasyatidae, found throughout the nearshore waters of the tropical Indo-Pacific, as well as off islands in the eastern Pacific. It is a bottom-dwelling inhabitant of lagoons, estuaries, and reefs, generally at a depth of 20–60 m. Reaching 1.8 m across, this large ray is characterized by a thick, rounded pectoral fin disc covered by small tubercles on top, and a relatively short tail bearing a deep ventral fin fold. In addition, it has a variable but distinctive light and dark mottled pattern on its upper surface, and a black tail.
  Generally nocturnal, the round ribbontail ray can be solitary or gregarious, and is an active predator of small, benthic molluscs, crustaceans, and bony fishes. It is aplacental viviparous, with the embryos sustained by yolk, and later histotroph secreted by the mother; up to seven pups are born at a time. Although not aggressive, if provoked the round ribbontail ray will defend itself with its venomous tail spine, and it has been responsible for at least one fatality. It is valued by ecotourist divers and recreational anglers.
context_section_description: The round ribbontail ray has nocturnal habits and rests motionless for much of the day, often near vertical structures, in caves, or under ledges. It may be solitary, or form small to large groups. This ray is frequently shadowed by one or more jacks or cobia (Rachycentron canadum); these smaller fishes may feed on food stirred up by the ray's activities, or use the ray's body as cover for approaching their own prey. The round ribbontail ray hunts for bivalves, crabs, shrimps, and small bony fishes on the bottom. When feeding, it adopts a characteristic posture in which it presses the margin of its disc against the bottom and takes in water through its spiracles, which it blows through its mouth to uncover prey buried in the sediment. This species may fall prey to larger fishes such as sharks, and marine mammals. When threatened, it raises its tail over its back so that the spine faces forward, and waves it back and forth. Known parasites of this species include the monogenean Dasybatotrema spinosum, Dendromonocotyle pipinna, Neoentobdella garneri and N. taiwanensis, and the nematode Echinocephalus overstreeti.
  Little information is available on the life history of the round ribbontail ray. Like other stingrays, it is aplacental viviparous: the unborn embryos are initially sustained by yolk, which is later supplemented by histotroph ("uterine milk", containing proteins, lipids, and mucus) produced by the mother. Reproductive aggregations numbering in the hundreds have been observed at Cocos Island shortly after the onset of La Niña, which brings cooler temperatures. During these periods a single female may be pursued by dozens of males. Females bear litters of up to seven pups, each measuring 33–35 cm (13–14 in) across and 67 cm (26 in) long. Off South Africa, birthing may take place in the summer. Males attain sexual maturity at a disc width of 1.0–1.1 m (3.3–3.6 ft); the maturation size of females is unknown.
caption: The round ribbontail ray is relatively inactive during the day, often resting on sand near reef structures.
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