page_title: Sixgill stingray
section_title: Biology and ecology
hierarchical_section_title: Sixgill stingray / Biology and ecology
caption_attribution_description: English: Cookiecutter shark (Isistius brasiliensis)
context_page_description: The sixgill stingray is a species of stingray and the only extant member of the family Hexatrygonidae. Although several species of sixgill stingrays have been described historically, they may represent variations in a single, widespread species. This flabby, heavy-bodied fish, described only in 1980, is unique among rays in having six pairs of gill slits rather than five. Growing up to 1.7 m long, it has a rounded pectoral fin disc and a long, triangular, and flexible snout filled with a gelatinous substance. It is brownish above and white below, and lacks dermal denticles.
  Benthic in nature, the sixgill stingray is usually found over upper continental slopes and seamounts at depths of 500–1,120 m. It has been recorded from scattered locations in the Indo-Pacific from South Africa to Hawaii. This species probably uses its snout to probe for food in the bottom sediment. Its jaws are greatly protrusible, allowing it to capture buried prey. The sixgill stingray gives live birth, with litters of two to five pups. The IUCN has assessed this ray as Least Concern, because it faces minimal fishing pressure across most of its range.
context_section_description: The long snout of the sixgill stingray is very flexible both vertically and horizontally, suggesting that the ray uses it to probe for food in the bottom sediment. The underside of the snout is covered by well-developed ampullae of Lorenzini arranged in longitudinal rows, which are capable of detecting the minute electric fields produced by other organisms. The mouth can be protruded downward farther than the length of the head, likely allowing the ray to extract buried prey. The jaws are poorly mineralized, suggesting that it does not feed on hard-shelled animals. There is a record of a specimen with a wound from a cookiecutter shark (Isistius brasiliensis). Reproduction in the sixgill stingray is viviparous, with documented litter sizes of between two and five pups. Newly born rays measure around 48 cm (19 in) long. Both males and females mature sexually at approximately 1.1 m (3.6 ft) long.
caption: The cookiecutter shark is known to bite the sixgill stingray.
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