Science & Tech

Groundbreaking footage shows how hammerhead sharks get their hammers

Groundbreaking footage shows how hammerhead sharks get their hammers
Hammerhead shark swims under woman paddleboarding

Hammerhead sharks are named that for a fairly obvious reason, but now groundbreaking footage has emerged which shows exactly how their unique head shape occurs.

The strange-looking hammerhead shark has a very broad nose and spaced-out eyes that lend to its name and make it one of the most bizarre-looking sharks out there.

Scientists studying the creature have until now had no idea how their hammers form, but now researchers have gotten a glimpse thanks to new footage.

The species’ embryonic development is notoriously hard to study as they don’t lay eggs, so experts instead have been helped by the bonnethead sharks (Sphyrna tiburo), the smallest hammerhead species which is commonly found in estuaries and waters in the Gulf of Mexico and the Western North Atlantic Ocean.

In a study published in Developmental Dynamics, researchers looked at embryos that had been preserved from bonnetheads that had been caught in previous studies to ensure that no additional sharks were affected.

They studied embryos of the sharks at different stages of their development and witnessed as the shark's head started to form its unique shape.


The team found that the bonnetheads develop their head early on in their development, but the hammer doesn’t begin to form until around halfway through their gestation when the cartilage that forms the hammer begins to expand from the nasal area.

The lead author, Steven Byrum, explained: “It’s the perfect qualities of the bonnethead that allowed us [to] do it with this species.

“This was a unique opportunity we may not be able to get for very much longer with bonnetheads and may not be able to get in any other species of hammerhead.”

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