Birds and vacationing humans aren’t the only animals to migrate south for the cold months of winter. It turns out that basking sharks do, too.
They are the ocean‘s second largest fish, and live in temperate waters from late spring until early fall. But then they disappear, and until now scientists have only been able to guess where they go–some have even suggested that the sharks hibernate on the ocean floor. To find the real answer, the team tagged 25 basking sharks off the coast of Cape Cod and tracked them as they made their wintertime trip. The researchers found that the sharks headed south [to the Caribbean], some going as far as Brazil [Science News].
The basking shark is a benign behemoth. It swims at about three miles per hour with its four-foot-wide mouth gaping open, filtering through almost 500,000 gallons of water every hour for its plankton sustenance [Wired]. They can grow to 35 feet or longer, but aside from knowing the sharks spend most of their time in temperate waters, scientists have been mystified by these fish for years: no one has ever examined a newborn basking shark. No one has seen a pregnant female. No one knows where the animals give birth [Discovery News].
In the new study, published in Current Biology, the researchers also found that despite basking sharks’ tendency to swim near the ocean surface in the spring and summer, the sharks made their winter journeys at depths of 200 to 1,000 meters and stayed at those depths for weeks or months at a time [Science News]. Researchers say that may explain why the sharks have never before been spotted during their southern sojourns.
The findings are surprising, since basking sharks were previously thought to spend all their time in cooler waters. “This is equivalent to finding polar bears in Kansas” [Discovery News], said lead researcher Greg Skomal. But it’s still not clear what drives the sharks to embark on such a long, depleting journey every year. Skomal hypothesizes that these migrations might be linked to reproduction, with females seeking a tropical nursery where they can give birth [Nature News], while other researchers suggest the sharks may be looking for rich plankton feeding grounds.
Related Content:
80beats: Female Shark Gets Pregnant on Her Own, No Male Required
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Image: Chris Gotschalk
May 7th, 2009 at 8:18 pm
Interesting info
May 8th, 2009 at 6:34 am
What a remarkable picture of an even more remarkable animal. Thank You
May 8th, 2009 at 12:48 pm
So cool.
May 11th, 2009 at 12:13 am
Wow, now I can sleep nights knowing where giant mouthed sharks winter. Thank you for that much needed to know fact of life.
Can’t our government find a better way to piss our tax payers money away. Maybe like feeding people who truely need the help. Oh God no. Don’t do that. Lets spend millions more so we can see a pregnant female. WTF.
May 11th, 2009 at 1:33 am
It is nice to see that some people still take an active roll in researching such a great creature in our wildlife. I hardly think tagging a few sharks would be pissing away tax payers dollars if it helps to stop the extinction of this wonderful creature.
May 11th, 2009 at 3:29 pm
Gee John maybe you should grind that axe a little harder! Let’s not study anything and keep our heads in the sand like you do! Yes, that will be good for the planet. Let’s not find out how anything works and then we won’t have to worry about it because we’ll all be DEAD.
Good job John, I’m so glad that we have people like you commenting on things…go back to sleep.
May 11th, 2009 at 6:39 pm
Still no cure for cancer. . .
May 11th, 2009 at 8:08 pm
Somebody order a pizza?
Sharks have many contributions to make to science, and we need to maximize ocean populations to feed the billions of people here. Research can help us all.
Now open the door.
May 15th, 2009 at 5:19 am
well i for one feel that its w0nderful to know as much as possible about every living creature that we SHARE this amazing planet with . And especially since more of the earth is actually water than land and we still know so little about so much of the deep blue sea.Research on .. besides I didn’t see anywhere it said Americans were footing the bill. I believe that often there are many different organizations that fund these things on a world wide level. Not everything revolves around you tightwads!
June 23rd, 2009 at 4:48 pm
no Jeff, it’s not time to thaw out The Duke yet…
June 26th, 2009 at 11:58 am
@ Jeff
If your’e not a cancer researcher, go become one.