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Smooth
Hammerhead Shark Sphyrna zygaena
| Photo modified from
Sharks and Rays. TC Tricas, K Deacon, P Last, JE McCosker, TI Walker, L
Taylor. 1997. Nature Company Guides, Time Life Book Series. Weldon Owen Pty Ltd
San Francisco. |
The hammerhead sharks are
easy to distinguish from other sharks because of the characteristic compressed
head. The cephalophoil, or head, is a broad and flattened skull that gives this
shark its distinguished shape. However, within the hammerhead family there are
several species that are differentiated by subtle differences in the shape of
the cephalophoil. The smooth hammerhead is the only one that appears in
Canadian waters and is characterized by a head that lacks a central
indentation, hence the name. This shark is white underneath turning to brownish
gray or a deep olive colour on top. The teeth, which are similar on both the
upper and lower jaw, are triangular and smooth-edged. Adults of this species
can attain lengths up to 3.7 to 4 meters (12 to 13 feet) and can weigh in
excess of 400 kg (880 lbs).
 |
| Photo modified from
Sharks and Rays. TC Tricas, K Deacon, P Last, JE McCosker, TI Walker, L
Taylor. 1997. Nature Company Guides, Time Life Book Series. Weldon Owen Pty Ltd
San Francisco. |
Diet
The smooth hammerhead
feeds on schooling fish such as herring and menhaden. Other animals in their
diet include other sharks (its own species included), shrimp, skates,
crustaceans and cephalopods.
Reproduction
The smooth hammerhead is a
viviparous species that gives birth to a large litter, between 20 to 40 pups.
The pups are usually 50cm (20 inches) long at birth. Individuals become
sexually mature at 2.3 meters (7.5 feet).
Habitat
The smooth hammerhead
shark is distributed worldwide. They occur in all warm temperate waters but are
rare in tropical waters. It prefers inshore waters less than 20 meters (65
feet). These sharks occur at the surface in the open ocean and often form
enormous schools during migration to cooler latitudes during the summer
months.
Range
This shark can be found in
the western and eastern North Atlantic and in the Indian Ocean. In the western
Atlantic the smooth hammerhead ranges from Nova Scotia to Florida. This shark
has been reported in Nova Scotian waters off Herring Cove, Sambro Light and
Brier Island as well as in St. Margaret's Bay and on the northeast tip of
Georges Bank.

Distinguishing
Characteristics
- Hammer-shaped head that lacks a central
indentation
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