Shark Colors 61
The Megamouth Shark, one of the victims of Cookiecutters, was at first
considered a light emitter, producing a glow from its upper lip region that
might attract plankton prey. This idea is unproven, either by observation of
healthy live animals (unlikely) or by histological (microscopic) examination
of mouth tissues, yet to be done. It is more likely that the distinctive white
band of tissue along the upper jaw reflects dim light at midwater depths.
The glow could attract prey animals, or it could be a species identification
tag used by other Megamouths. In truth, we don’t know the function of the
unique white oral band in this species.
Are any sharks colorless?
Albinism occurs in animals because of a malfunction in the gene re-
sponsible for producing melanin pigment. A true albino shark is almost
white (in underwater photos albinos appear to glow) and has pink eyes.
Such specimens are rare and most often involve embryos or newborns. Few
true albinos live long because they lack the coloration necessary to protect
them from a variety of large, visually hunting predators. The rarity also
means that just about anytime someone finds an albino shark, or even a
partial albino, the discovery gets published in a scientific journal.
Albino embryos (often removed from a dead shark’s uterus) or very
young albino individuals are known in the Gray Smoothhound Shark (Mus-
telus californicus), the Whitespotted Bamboo Shark, the Leopard Shark, the
Sandbar Shark, the Tiger Shark, the White-Spotted Marble Electric Ray
(Torpedo marmorata), and the Common Torpedo (Torpedo torpedo). Albino
Brownbanded Bamboo Catsharks have been born to a captive, normally
colored female at the Denver Downtown Aquarium. The fish collection at
Rhodes University in Grahamstown, South Africa, has a real white shark,
or rather a very young albino White Shark 1.7 m (5.6 ft) long. Most bizarre
is a 22-inch-long (56-cm-long) albino Dusky Shark (Carcharhinus obscurus)
embryo that was removed from a pregnant female by a fisherman in the Sea
of Cortez, Mexico, in 2011. What made this find truly strange was that it
was a cyclops. It lacked normal eyes but had one fully developed, forward
pointing eye between its mouth and snout.
Full-grown albino sharks do occur and are even sometimes photo-
graphed in the wild. Species include a Narrownose Smooth-hound (Mus-
telus schmitti), an adult Tawny Nurse Shark (Nebrius ferrugineus), and a Ha-
lave’s Guitarfish (Rhinobatos halavi). An albinistic adult male Sand Tiger was
filmed off the New South Wales coast of Australia in 2007, and the same
month, a 10-m (33-ft) female albino Whale Shark was glimpsed and even
videotaped near Darwin Island, Galapagos. That same year—a seemingly
big year for albinos—a 12-inch-long (30-cm) juvenile female albino Spot-