Cookiecutter Shark

About the Cookiecutter Shark

The Cookiecutter shark, also called the cigar shark, is a species of small dogfish shark in the family Dalatiidae. Its name refers to its feeding habit of gouging round plugs of flesh, as if they had been cut out with a cookie cutter.

Description

The cookiecutter shark has an elongated, cigar-shaped body with a short, bulbously rounded snout. Its large, oval, green eyes are placed toward the front of the head. The upper jaw has 30–37 tooth rows, and the lower jaw has 25–31 tooth rows. The pectoral fins are short and trapezoidal in shape. Two spineless dorsal fins are positioned toward the rear of the body and are similar in size. There is no anal fin, and the caudal fin is broad, with a long lower lobe. The fins have pale margins, except for the caudal fin, which has a dark tip.

Complex, light-producing organs called photophores densely cover the entire underside, except for the collar, and produce a vivid green glow. The maximum recorded length for this species is 42 cm (16.5 in) for males and 56 cm (22.0 in) for females.

Biology and Behaviour

The cookiecutter shark regularly replaces its teeth like other sharks, but it sheds its lower teeth in complete rows rather than individually. The retina of the Cookiecutter shark has ganglion cells, a type of neuron located near the inner surface of the retina. These cells are concentrated in a concentric area rather than a horizontal streak across the visual field. This may help sharks focus on prey in front of them.

The cookiecutter shark feeds on medium to large oceanic animals that share its habitat. It is considered a facultative ectoparasite because it removes plugs of flesh from temporary hosts. Bite marks have been found on cetaceans, pinnipeds, dugongs, sharks, stingrays, and bony fishes. It also hunts and eats entire squid and crustaceans.

Reproduction

Like other dogfish sharks, the Cookiecutter shark is ovoviviparous, meaning that embryos develop inside eggs within the female’s uterus and are sustained by the yolk until birth. Females have two functioning uteri and give birth to litters of 6 to 12 pups. Newborn sharks measure 14 to 15 cm (5.5–5.9 in) long. Males attain sexual maturity at around 31–37 cm (12.2–14.6 in), and females at 38–44 cm (15.0–17.3 in).

Habitat

The Cookiecutter shark is a widespread oceanic species that occurs mainly in temperate and tropical waters. Based on catch records, this species appears to conduct a diel vertical migration up to 3 km (1.86 mi) each way. It spends the day at depths of 1,000–3,700 m (3,280–12,139 ft), and at night it rises into the upper water column, usually remaining below 85 m (279 ft). This species may be more tolerant to low dissolved oxygen levels than other sharks in the related genera.

Its distribution extends from the western Atlantic (Bahamas and Southern Brazil), the eastern Atlantic (Cape Verde, Guinea to Sierra Leone, Southern Angola and South Africa, and Ascension Island), the Indo-Pacific (Mauritius to New Guinea, Lord Howe Island, and New Zealand, North of Japan, and east of Hawaiian Islands), and the eastern Pacific (Easter Island and the Galapagos).

Conservation

This species is not of commercial value because of its small size, but it is occasionally taken as bycatch in oceanic trawl and longline fisheries. There are currently no conservation measures in place for this species.

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Cookiecutter Shark Gallery