Sex it! Identifying males versus females

Posted on October 16, 2008
Written by: Shark Savers

October 15, 2008

Have you been lucky lately?

It has been a good month for sightings since our last edition. At least 5 confirmed whale sharks were seen (3 males, 1 female, 1 unknown). Thank you to Captain Morgan, Utila Watersports, Deep Blue & Laguna Beach Resorts for submitting those Encounter Forms.
Loads of dolphins were also around to everyone’s delight.

I am also happy to report that the Code of Conduct ratio of 8 snorkelers to 1 whale shark was widely respected, resulting in safe encounters.
Bravo for being the good guys!

Boys & Girls


Whale shark claspers
Whale shark claspers

An important thing to check when in the water with a whale shark is if it is male or female. Most other countries studying them report that approximately 80% of the animals are male. Where are the girls? Is it the case for Utila?
We don’t know.. yet. So let’s get down there and have a look. Male sharks have 2 penises called claspers situated between the pelvic fins -the fins on the underside of the animal, just before the tail. The divemaster/instructor must go under the shark (on snorkling gear only & make sure it is safe according to your dive profile!) to see them.

But wait: Juvenile males have small claspers and are easily mistaken for female. If you are unsure of the sex then write UNKNOWN on the Encounter Form. Or to make it easy on yourself, why not take a photo if possible.

That’s all the news fit to print for now. I will be out of town for a little while but will still be sending you this monthly newsletter via email. Please keep those Encounter Forms coming, either walk to the wonderful people of the Utila Centre for Marine Ecology (UCME) or keep them at your dive centre, they will get picked up at a later date. You can reach me for any enquiries at

Let’s keep in contact and see you soon,

Isabelle Foisy