The cookiecutter shark specimen (Isistius sp.; CAS:ICH:222996) housed at the California Academy of Sciences. (Image Credit: Ben Young Landis/CC-BY)
Last Thursday, I satisfied some serious fish geekery cravings at Nightlife, the fantastic science outreach gala hosted weekly by the California Academy of Sciences in San Francisco. Think couples and singles enjoying wine and cocktails, DJ’s and games inside a world-class science museum, and you get the idea.
Cal Academy is famous for its Steinhart Aquarium, home to 38,000-some living specimens, as well as its Department of Ichthyology, which houses roughly 1.2 million specimens representing nearly 11,000 species.
Needless to say, it was a thrilling night of fishspotting — with much credit to the museum’s researchers and their dedication to public outreach.
Leading up to Thursday, the museum posted a question on the party’s Facebook Event page:
Anyone have any requests for unusual, small fish specimens they would like to see Thursday night? Ask and you may receive ( ;
What would be something cool and rare to see up close, I thought to myself. I decided to suggest the cookiecutter shark — and to my surprise, my comment got a response from Dr. Luiz Rocha, assistant curator of the Department of Ichthyology:
Oh, cookiecutter, that is a good one, I will see if I can find one in good shape…
Dr. Luiz Rocha, assistant curator of ichthyology at the California Academy of Sciences, shows off a cookiecutter shark specimen and a tiger shark jaw. (Image Credit: Jose G. Gonzalez)
Fast forward to Thursday night. After few sips of sangria and Moscow Mules, my friends and I wandered over to the ichthyology table, where lo and behold, Rocha had a specimen of the cookiecutter shark waiting.
“It’s actually our only specimen of the cookiecutter,” Rocha said. “Most of our researchers currently work on coral reef species, so we don’t have as many deep sea specimens.”
(This specimen is identified only as Isistius sp. in the collection records, but for simplicity’s sake we will discuss the best known species Isistius brasiliensis in this post.)
Cookiecutter sharks are called such because of their unique mouth and feeding habits. As you can see in the photo above, the mouth of this shark is shaped like a round suction cup, with an upper jaw full of needle-like teeth and the lower jaw equipped with rows of interconnected, saw-blade-like teeth.
This frightening combination of dental equipment allows these small sharks — under two feet (60 cm) in length — to feed on and inflict gruesome damage to creatures much larger than itself — even great white sharks (Hoyos-Padilla et al. 2013).
Each bite is like a melon baller digging out ripe melon — or a cookie cutter carving out a round piece of soft dough:
A sickle pomfret (Taractichthys steindachneri) with cookiecutter shark wounds. (Image Credit: NOAA Pacific Islands Fisheries Science Center)
Cookiecutter shark wounds on a Longman’s beaked whale (Indopacetus pacificus). Image Credit: Hawaii Pacific University/NOAA)
A specimen of Isistius brasiliensis housed at the Florida Museum of Natural History. (Image Credit: Florida Museum of Natural History)
Isistius brasiliensis, the cookiecutter shark. (Image Credit: NOAA Fisheries Service Pacific Islands Regional Office)
There is one documented attack by a cookiecutter shark on a human swimmer (Honebrink et al. 2011). However, the person was attempting a long-distance swim over tropical, open waters at night — the prime feeding zone and feeding time for the cookiecutter. Cookiecutter sharks live in waters below 3,000 feet deep during the day, but at night, they migrate towards the ocean surface to feed. These sharks also have bioluminescent spots on their belly — meaning they can glow in the dark — a common feature on many deep sea creatures.
(Addendum: Here is a 2011 interview with the swimmer by Dr. Alistair Dove over at Deep Sea News.)
Many thanks to Dr. Rocha for showcasing this unique and strange shark to the public — a species very few of us would be lucky (or unlucky) enough to encounter in person. And a tip of the hat to the California Academy of Sciences for continuing public outreach programs like Nightlife — proving without a doubt that science and learning can be hip and fun — even for grownups.
Isistius brasiliensis (Quoy & Gaimard, 1824)
Cookiecutter Shark
Click for name etymology (ETYFish Project)
Click for names in other languages (FishBase)
Class Chondrichthyes (Cartilaginous Fishes)
Order Squaliformes (Dogfish Sharks)
Family Dalatiidae (Kitefin Sharks)
FishBase Page: http://fishbase.org/summary/696
Citations
– Ben Young Landis
Better Know a Fish! 
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