HOW TO TELL MALE AND FEMALE HAMMERHEADS APART
Ever wondered how scientists can tell a male hammerhead from a female? The secret lies in a small but important feature, claspers.
What are claspers?
Claspers are special reproductive organs found only in male sharks. They’re paired, rod-like structures located on the inner edge of the pelvic fins, that’s the pair of larger fins near the shark’s tail.
How to spot them:
🦈 ♂️ Males: Look for two long, narrow claspers extending from the pelvic fins. They’re easy to see in clear underwater videos or when a shark swims overhead.
🦈 ♀️ Females: Have smooth pelvic fins with no claspers at all.
You can think of claspers as the shark equivalent of external reproductive organs. During mating, males use them to transfer sperm to females.
So next time you spot a hammerhead on your dive take a closer look! You might be able to tell if it’s a male or female just by noticing what’s (not) between those pelvic fins.
Why this matters:
Knowing the sex of hammerheads helps scientists track population structure, mating patterns, and habitat use, all key to protecting these endangered sharks.
Male smooth hammerhead (S. zygaena) with circled claspers - Marine Futures Lab - All rights reserved
Female scalloped hammerhead (S. lewini) with circled pelvic fins without claspers - Marine Futures Lab - All rights reserved
Tip: Check our YouTube video “How to Tell Male and Female Hammerheads Apart” to see claspers clearly recorded by our BRUVS cameras!