page_title: Tawny nurse shark
section_title: Description
hierarchical_section_title: Tawny nurse shark / Description
caption_attribution_description: Tawny nurse shark (Nebrius ferrugineus) off Broome, Western Australia.
context_page_description: The tawny nurse shark is a species of carpet shark in the family Ginglymostomatidae, and the only extant member of the genus Nebrius.
  It is found widely along coastlines in the Indo-Pacific, preferring reefs, sandy flats, and seagrass beds from very shallow water to a depth of 70 m. With a cylindrical body and a broad, flattened head, the tawny nurse shark is quite similar in appearance to the nurse shark of the Atlantic and East Pacific, from which it can be distinguished by its pointed-tipped dorsal fins and narrow, sickle-shaped pectoral fins. The maximum recorded length of the tawny nurse shark is 3.2 m.
  Nocturnal in habits, the tawny nurse shark tends to spend the day resting in piles of two dozen or more individuals inside caves or under ledges. At night, it is an active-swimming predator that uses a powerful suction force to extract prey from inside holes and crevices. The diet of this species consists mainly of octopus, though they also take other invertebrates, small bony fishes, and rarely sea snakes. It is aplacental viviparous, meaning the embryos hatch from egg capsules inside the mother.
context_section_description: The tawny nurse shark grows to a maximum length of 3.2 m (10 ft). It has a robust, cylindrical body with a broadly rounded and flattened head. The eyes are small and face laterally, with prominent ridges over them and smaller spiracles behind. There are a pair of long, slender barbels in front of the nostrils. The mouth is small, with the lower lip divided into three lobes. There are 29–33 tooth rows in the upper jaw and 26–28 tooth rows in the lower jaw, arranged in an imbricate (overlapping) pattern with the outermost 2–4 functional rows separated from the rest by a narrow space. Each tooth resembles a fan, with a broad base rising to a small, sharp central point flanked by 3 or more smaller cusps on both sides. As the shark ages, the teeth become relatively taller and thicker. The fourth and fifth pairs of gill slits are placed much closer together than the others.
  The dorsal and pelvic fins are angular, with the first dorsal fin larger than the second. The pectoral fins are narrow, pointed, and falcate (sickle-shaped); their shape separates this species from the similar-looking nurse shark. The origin of the first dorsal fin is about even with the origin of the pelvic fins, while the origin of the anal fin is even with or somewhat behind the origin of the second dorsal fin. The caudal fin has a shallow upper lobe and barely present lower lobe, comprising about a quarter of the total length in adults. The dermal denticles are diamond-shaped, bearing 4–5 faint ridges radiating from a blunt point. Tawny nurse sharks are yellowish, reddish, or grayish brown above and off-white below, and are capable of slowly changing their color to better blend with the environment. Young sharks have starkly white lower eyelids.
  Many tawny nurse sharks found off the coasts of Japan, Taiwan, and the Ryukyu Islands lack a second dorsal fin. This physical abnormality has been speculated to result from pregnant females being exposed to water of unusually high salinity and/or temperature, possibly from human activity. In 1986, a 2.9 m (9 ft 6 in) long adult male with both a missing dorsal fin and partial albinism (in the form of white body color with gray-brown eyes) was captured off Wakayama Prefecture, Japan. This anomalous individual is the largest albino shark known to date, having survived for a long time in the wild despite its lack of camouflage.
caption: The sickle-shaped pectoral fins of the tawny nurse shark are one of its characteristic traits.
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