Monday, May 25, 2009
In honor of the beginning of Shark Summer here at the Aquarium of the Pacific, I thought I’d tell you about one of my favorite local sharks – the horn shark!
When you think of sharks, you may think of the “big guys” – great whites, hammerheads, tiger sharks. Those species are awesome and cool looking, but the reality is that there are dozens of other shark species filling our oceans that are just as interesting!
One very unique species of shark that you can find along our shores is the horn shark (Heterodontus francisci). This species of shark can be found along the seafloor around kelp beds and rocky shores. Catalina is an ideal place to find them, day or night, but they have also been spotted around Laguna Beach and Huntington Beach. They are also very common in the Channel Islands area.
The horn shark gets it’s name not from the horn-like bumps on top of it’s head, but because of the long sharp spine that extends from it’s dorsal fin. This spine is most likely a defensive feature to protect the shark from being eaten.
Horn sharks are not good swimmers, so they live along the sea floor and stay in fairly small general areas. They have very strong pectoral fins and crawl along the sea floor, living in waters that are usually less than 40 feet deep. Horn Sharks average around 3-4 feet long as adults.
They eat small fish and invertebrates along the sea floor. Some individuals especially like sea urchins and it’s been reported that the horn sharks who eat lots of purple urchins tend to have purplish-colored spines due to the diet.
Horn sharks breed by laying eggs, and they lay the coolest eggs! The mother lays the eggs in the cracks and crevices of the rocky sea floor. The eggs come out soft in a curled spiral shape – like the tip of an auger or drill bit. The egg then hardens in the crevice and becomes near impossible to pull out of the crevice. It would be like trying to pull a drill bit out of a piece of metal you’ve drilled deeply into! What an awesome way to protect the eggs!
We have several Horn Sharks here at the Aquarium. Recently the aquarists in the Southern California/Baja Gallery set up a new display tank for baby sharks. Here we have two small horn sharks on display along with three baby swell sharks. The spiraled horn shark eggs and purse-shaped swell shark eggs are also shown in the display.
One of my favorite things about the horn shark is how brave they are. I have the wonderful opportunity to feed the juvenile horn sharks on display. When they hear my footsteps on the ladder and see me above them, they immediately move closer to be fed!
We feed them a small variety of fish, shrimp, and clam. I chop the food into tiny dime sized bites and place the bites on a feeding stick one by one. The sharks swim straight for the stick and bite down as soon as the food gets close. Sometimes the food is stuck to the feeding stick so they’ll even give the food a good thrashing to pull it off the stick. Pretty impressive to watch!
In their natural environment, horn sharks are harmless to people. Normally, they are fairly docile and would probably just sit perfectly still on the sea floor and watch you swim by. If harassed though, they would boldly protect themselves from a seal, larger shark, or even a pushy diver. While their mouths are too small to do any serious damage, I’m impressed by their bravery to stand up for themselves regardless of size.
If you have the opportunity to do some local diving, be sure to keep a look out for my favorite local shark – the horn shark. The next time you come to the Aquarium be sure to stop by the baby shark and shark egg display in the SoCal/Baja Gallery. Maybe you’ll get to see me feed them!
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