Conservation Status: Critically Endangered
Scientific Name: Sphyrna Lewini
The Galapagos Islands are one of the most abundant regions on the planet to find the Hammerhead Shark – literally thousands call the archipelago home, making for world class snorkelling and diving. Here, Scalloped Hammerhead Sharks gather together in large schools, and Hammerhead nurseries can also be found, while other species such as the Smooth Hammerhead and Great Hammerhead may also sometimes be spotted.
Of course a Hammerhead Shark is easy to recognise thanks to their unique head (cephalofoil) that is shaped like a hammer, with eyes on either side. This feature improves their vision by providing an increased area of electroreceptors, allowing them to scan the ocean effectively to sense prey and predators.
A Scalloped Hammerhead Shark differs from their close cousins by the ‘scalloped’ front edge of their head. A Hammerheads body is slim and streamlined, coloured brown on top and white underneath. Narrow teeth form backwards triangles, perfect for hunting and seizing their prey. Baby sharks measure 50 centimeters long, while adults grow to around four meters or more.
Where to See Them: In large schools at Darwin and Wolf Islands. They can also sometimes be seen at Gordon Rocks (dive site), and Kicker Rock (dive and snorkel site).
When to See Them: Year-round, especially in the warmer months from December to April, with the largest schools visible in January.
A close encounter diving or snorkelling with Hammerhead Sharks is without doubt one of the very top Galapagos experiences, one that stays with lucky visitors for the rest of their lives. The best chance is way up north at Darwin and Wolf islands, which can only be visited on a specialised Live-aboard Scuba Cruise – the early months of the year are optimal. A good alternative is to take a dive day tour at Gordons Rocks or Kicker Rock and keep your fingers crossed for a sighting.
Hammerhead species breed by viviparous reproduction – pups are fed via a placental link inside the mother, and are born alive and ready to swim. They have a long gestation period, usually from 9-12 months, and give birth to 12-40 pups at a time. The young are left together in nurseries in shallow coastal waters such as flooded mangrove forests, which provide both food and protection. Here the pups slowly grow for one or two years, until ready to fend for themselves in the open ocean. Predation from other shark species is common, so this is a dangerous period in the lives of a young Hammerhead Shark, without their mother.
At Galapagos, a Hammerhead Shark diet consists of fish, preferably sardine, herring or mackerel, and occasionally stingray, squid or crustaceans. Hammerheads are adept hunters, moving quickly and stealthily, and capable of turning 360 degrees in a split second to capture their prey.
Unfortunately the Scalloped Hammerhead is a Critically Endangered species, frequently targeted by illegal fishing due to the high value of their fins in the Asian market. They are also at risk to bycatch of trawlers and long-line fishing, where they become trapped and drown.
If you enjoyed this article, then check out our blog about Whale Sharks at Galapagos – another great diving experience.
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