Headbutting fish

In the wild, male animals use headbutting to defend their territory, among other things. We have always thought of land animals, like bison and rams, as the ones that headbutt.  Now we know that fish do it, too.  Specifically, the giant bumphead parrotfish.

The bumphead parrotfish was named for the giant bump on the front of its head.  Turns out they also actually bump heads under water. You can see them doing it here:

Bumphead parrotfish headbutting

It’s hard to tell from the pictures, but these are huge fish.  They can grow four to five feet long and weigh 100 pounds, making some of them as big as a 13-year old.  They are also a potentially endangered species (PDF).  Their lifestyle makes them easy targets for overfishing: they hang out in groups in shallow water, where spearfishers get them.  The fish have learned, though, and are now skittish of humans.  It’s hard to know what they do when no one’s watching:  there aren’t many of them around, and when do we find them, they quickly swim away.

There are a few marine areas where bumphead parrotfish are protected.  In these areas the fish still thrive, and they don’t know to be afraid of people.  It was in one of these areas that scientists first heard, and then saw, the fish headbutting.

People thought that the fish use their heads to bump into the reef and break off chunks to eat.  However, the bony plates on female heads are not as big as the ones on males, and the females have no trouble eating (you can see a picture of the male/female difference in the original paper).  Now we may know what those plates are really used for:  a mating ritual, and territorial defense.

Headbutting aside, the bumphead parrotfish are thought to be gentle giants.  Their diet mainly consists of coral reef. In fact, they are the biggest plant-eating fish on coral reefs. Being so big, they can eat a lot: up to five tons of reef each year, per fish.  No other fish eats that much reef, and without the bumphead parrotfish, the reef would just keep growing.

The scientists observed the fish in the video at Great Barrier Reef off the coast of Australia, where are still plenty of bumphead parrotfish.  The fish eat the reef as fast as it grows. Without them chomping away on it, the whole reef would change, and probably for the worse: the reef would get too big and become unstable.  Also, different species would move in.  This would disrupt the ecology of the entire reef system.

The scientists’ discovery was a surprise benefit of bumphead parrotfish protection.  Not only is the reef healthier, and the fish are surviving, but we’ve also learned something totally unexpected about fish. And that’s what science is all about!

Note:  This is my the first “Family Day at The Beach” post.  Try sharing it with kids.  I’d love to hear what you think.

Image credit:  http://underwater.com.au/image/id/9476/

Please pass the science

I was once a high school science teacher. From there, I found my way back to the lab, and then into graduate school, and now I suppose I’m officially a scientist.  However, seven moves later, I’m still carting around boxes of my old teaching materials.

As they follow me, so too the question: how do we do a better job of educating students in science and math?

The Program for International Student Assessment, or PISA, is a test given every year to 15-year olds around the world.  Students are tested for math, science, and reading competence.  The US is not kicking butt.  In 2009, we ranked 31st in math (below average) and 23rd in science (about average).

Being number one on tests like PISA may come at a cost, such as a more structured and rigorous childhood.  When I was young, I had the freedom to just be a kid.  My childhood involved healthy doses of goofing off, reading, playing, and being bored.  At least that’s how I remember it.

But I was also part of a family that prioritized learning.  As early as first grade, my parents installed a desk in my bedroom, so that I would have a special place to do homework.

I couldn’t wait for my first assignment.

Kids love learning things.  Parents of young children realize this, and take time to teach their kids about the world.  When those same kids go off to school, there is no torch that gets passed from parents to the teachers that relieves parents of the responsibility to educate their children.

So I’d like to throw my two cents into the “how to improve science education” debate: talk about science at home. Let your kids be makers, or scientists in their own right.  You don’t even need to buy a chemistry kit, if that sounds scary and explosive.  Early scientists started out observing the world with basic, if any, equipment.

In case you are about to protest that you are unqualified (perhaps you were die-hard humanities major): you don’t need to be a scientist to encourage science. There is a lot of cool science out there for both kids and adults to love.  Science can have a place in anyone’s home. To that end, I’m going to give a shot at writing a few columns aimed at parents and kids.

In keeping with the blog’s theme, I’ll call it “Family Day at The Beach.”  My hope is that a good post might fuel a family dinner conversation.  My babbling baby is too young a test subject for this idea, and it could be a total flop when he gets to be old enough.  My son will probably be running the dinner show as soon as he can string together a few sentences. I won’t be able to get a non sequitur in edgewise.

How else will I bring up headbutting fish?