SHARK!

This post was written by Diana Birney, Supervising Marine Biologist for our upcoming SHARK! exhibit, opening August 29, 2015.

We fear them, we love them, and we are fascinated by them. We have a whole week on television dedicated to them that draws millions of viewers every year. Humans have an amazing obsession with this interesting group of animals, especially considering that we really don’t know that much about them.

It’s clear from the popularity of movies like Jaws and Sharknado that we love to be scared by sharks. While there is a good reason to give sharks their space, they are not the crazed “man-eaters” that Hollywood has often portrayed. In fact, since 1911 there have only been two deaths and less than fifty unprovoked attacks by sharks in Texas.

You’re actually more likely to be struck by lightning than you are to be attacked by a shark.

However, every time you enter a body of water, you should go in with the knowledge that a shark could potentially be there. When it comes down to it, it’s their space — not ours.

That doesn’t mean that you can never go in the water again, it just means be smart about what you do in the ocean…

So go to the beach, bring your sunscreen (and reapply it often!). But also bring your knowledge of what lives in the habitat you are about frolic in. Feel like you don’t know enough? Don’t worry! Here’s a nice set of guidelines for your next trip:

1. Sharks aren’t searching for humans to eat

There is no evidence to suggest that sharks like eating people. In fact, considering the numbers of people that go to the beach and the attack statistics, it would seem that sharks DON’T like eating people. A beach is a potential buffet at certain times of the year, but the sharks don’t seem to take advantage of it (good news for us!).

When people do get bitten, it’s usually one bite and the shark lets go. This is similar to the other night when I had a plate of broccoli I was going to town on and ran into a bite of mushroom (I hate mushrooms). I promptly spit that nasty bite out and went back to my broccoli feast (YUM). Sharks tend to follow schools of fish or, for our larger shark friends, mammals such as seals. Schools tend to frequent coast lines and often when someone is bitten there is a school of fish in the area that the shark was intending to chow down on.

2. Sharks have AMAZING noses

Sharks can sense blood in a ratio of one part per million. They also have sensors on their noses called ampullae of Lorenzini. These are electroreceptors that can sense the electrical field given off by everything swimming around in the ocean — including you and me! If a wounded person or animal enters the water, a shark can be drawn to the blood but also to the electrolytes that pour out of the wound as well.

There is a common idea that punching a shark on the nose will make it less likely to attack you. This stems from the fact that the ampullae are all over the nose and punching the shark might disrupt the electroreceptors. Another reason this (sometimes) works is that most sharks like certain prey items and most of those prey items don’t know how to punch — giving the shark a strong clue that it won’t like eating you. 

However, it’s important to not just go around punching sharks… right under their nose is a huge mouth with lots of teeth, and you may end up just losing an arm instead of scaring the sharks.

3. “There’s a chance I’ll bite if you bother me too long” – sharks

This summer there was a shark bite incident off of the coast of California with a White Shark. A swimmer got too close to a fishing line that caught a shark. The shark had been on the line long enough to be mad at everyone and everything. When the swimmer approached it, unaware it was even there, the shark lashed out. The moral of the story is that sharks, like dogs and cats, have no way to communicate with us that they are uncomfortable or in pain. The only avenue available is their teeth. Many bites are exploratory or just to say “BACK OFF.” 

A good rule of thumb in any environment is that if it has teeth it can/will bite.

4) Stay with your swimming buddy

Having a buddy is essential for beach safety. Rip tides can pull even proficient swimmers down and out into the ocean (and are actually much more likely to happen to you than a shark attack). Sharks, just like other apex predators, e.g., lions, tend to go after prey that is separated from the pack — it makes for an easy dinner.  So if you are swimming alone a shark might think you are a solitary prey item. If you are with someone else, the shark might still think you are prey, but will be less likely to attack a small “pack” rather than a solitary animal.

The buddy system is also beneficial just in case something does happen. Your buddy can get help and report exactly what happened in case you are in shock or missing.

 

5) Daytime is the best playtime

Most sharks hunt at night, dawn and dusk when they can see the best. Fortunately, most people go to the beach during the day. Just be extra careful if you are going out in the evening or at night because the shark can see you better than you can see them, guaranteed. However, if you are in an area frequented by White Sharks remember that they tend to hunt during the day when their traditional prey are more active.

6) Play smart

It’s important to know what signs indicate a higher chance of sharks in the area. Sandbars and the drop offs around sand bars are a common shark hang out. Sharks can swim in extremely shallow water, so don’t let the low water level lull you into a false sense of security.

An easy sign of sharks to watch out for is the presence of other animals. I know it’s hard to stay back when you see a bunch of fish in the water (as a Marine Biologist, I can be guilty of not staying away from schooling fish), but sharks enjoy snacking on large groups of fish. We wouldn’t want you to end up a morsel in the shark’s buffet.

However, we can’t always see schooling fish. Don’t worry too much since there are more obvious signs you can watch out for including: birds, dolphins/porpoises and lots of splashing. Birds will attack schools from the air, so if you see many birds diving in a particular spot, you can safely assume there are fish there and will want to stay away from that location. Same with dolphins and porpoises. They eat a lot of the same foods that sharks eat, so do not assume there are no sharks just because you see dolphins.  Splashing is also a key sign to sharks that prey is in the area since schools of fish tend to ascend and splash around near the surface. So, again, stay away from areas that show signs of splashing, and it’s also a good idea to keep your splashing around to a minimum.

7) Know your local sharks

It’s also good to know your local sharks. The Gulf of Mexico is home to many different species, some sharks you might not see — much less have to worry about. Others, like the Bull shark account for all of the Texas deaths from sharks (don’t be too alarmed, again, there have only been 2 since 1911). We also have thresher (my personal favorite shark), nurse, blacktip, tiger, many different hammerhead species, and many more.

If you followed the news this summer, you might have seen a White Shark named Katherine approaching Texas. Katherine shows us that we can get Great White Sharks in the Gulf. For more information on Katherine and many other tagged sharks you can go to OCEARCH.org. If you are travelling and plan on going to the water, it’s helpful to know what sharks are in the area and how likely your are to see them.

In the long run, it’s important to remember that shark interactions are NOT common, you just want to be prepared and armed with knowledge whenever you hit the beach.

The Houston Museum of Natural Science is teaming up with the Texas State Aquarium and OCEARCH to bring more information and awareness of sharks to Houston with our new SHARK! exhibit

Come visit to learn about (and even touch!) these amazing animals starting August 29!

Bakker blogs: Bulldozer worms and the end of peace on the ocean floor

Life first evolved about 3.5 billion years ago, at the beginning of the Precambrian Eras. At first, life was made up of simple microbes (bacteria) that could survive horrible conditions, including acid oceans and no oxygen in the air or water.

For 2.7 billion years, the sea bottom remained (mostly) peaceful, quiet and flat. Microbes built wide mats that sealed the mud surface, stabilizing the sediment.  Advanced microbes like blue-green algae began pumping oxygen into the atmosphere and ocean. The microbes had few enemies — no big, energetic animals disturbed the bottom. Day after day, week after week, year after year, bits of sediment kept falling down through the ocean water. The clay and silt continued to make layer after layer of sediment, and the ecosystem was stubbornly two-dimensional — all life lived on the surface or the bottom.  The subsurface was empty.

Then, around 700 million years ago, the Vendian Period began. A few life forms like Charnia and its kin got up to a half a foot tall, acquiring the shape of bloated feather plumes. Still, no one was churning up the mud or otherwise disturbing the microbial mats.

cactus worm left
Life in the Pre-Cambrian still was lovely, idyllic and BORING!

Today’s oceans teem with life forms that burrow through the bottom mud and live in cleverly constructed holes. Thousands of creatures, large and small, plow through the sediment looking for food. Plowers and burrowers include snails and bristle worms, long-necked clams and sea-cucumbers, plus a bewildering variety of groups without common names. The Precambrian world was totally devoid of all this action.

Finally and suddenly 540 million years ago, the Precambrian peace was broken. The Vendian Period ended when the microbial mats were attacked and ripped apart. Holes were excavated down into the mud. Bottom sediment was churned up. The long reign of the soft, quiet, two-dimensional world at last was terminated.

cactus worm right
The Cambrian Explosion had begun.

From this moment on, the rules of life were changed, and the ecosystem went into 3D. Dozens of new species evolved to take advantage of living deep in the mud. Other species hunted the species in the mud. Still more species swam above the surface looking for prey hiding below. Trilobites appeared and flourished. Fishy-things evolved.

Who destroyed the Precambrian mats? Who released the potential of evolution? Where do we send the thank-you note?

The fossil burrows are clues. At the end of the Vendian and the beginning of the Cambrian Period, U-shaped burrows appear all over the globe wherever shallow seas existed. Something was diving down through the mats and coming back up, again and again. This was the burrower who was destroying the ancient system of mats.

There are suspects alive today that make U-shaped burrows quite like the ones that ripped apart the Vendian bottom. Usually these critters are no bigger than a small pickle. Under the microscope, these burrowers look as fierce as the man-eating worms in the movie Tremors — the beasts have stout, muscular bodies with a face that carries a scary array of hooks and barbs. When they bump into prey, the hooks snag on their victim and the whole face inverts, dragging the meal into the throat.

800px-Priapulus_caudatusThe cactus worm, close-up.

You can find these mini-monsters in the mud in most oceans. Technically, they are called “Priapulida,” but they have many nick-names. Our favorite is “cactus worms.”  Because they have no bones or hard shells, cactus worms have almost zero chance of being fossilized unless there are very special conditions. The cactus worm would have to be buried instantly by an underwater landslide that killed the worm and sealed it under a thick blanket of sediment,  keeping out any scavengers.

For the first century of paleontological explorations, up until 1909, no one could find such an avalanche bed. Then Dr. Charles Doolittle Walcott, Cambrian expert from the Smithsonian Institution, hiked up into the Canadian Rockies near Burgess Peak in British Columbia.  He was looking for Cambrian trilobites, his specialty. He found what he was looking for flattened in dark slabs of clay, but there were other species, too — animals with no shell or hard parts at all.

Most exciting were the worms. Dozens of kinds of worms. Worms that ate microbes. Worms that ate trilobites. Worms that ate other worms (“Lutheran Worms”). Walcott had found the Holy Grail of Cambrian history.

But was there evidence of cactus worms? Yes!

Now we knew for certain that cactus worms had thrived in the transition from Vendian to Cambrian. We could be sure that these worms had overturned the Precambrian peace and begun the Cambrian Explosion.

They may be ugly, but remember these little creatures; they were the dynamos that restructured the oceanic world.

Science Doesn’t Sleep (9.4.08)

Released to Public: Astronaut Robert L. Curbeam, Jr., STS-116 Spacewalk (NASA)
“Houston…we’ve got a
SPAM problem.”
Creative Commons License photo credit:
pingnews.com

So here’s what went down after you logged off.

There’s a new Manhattan floating around the Arctic – and it’s made of ice. Canada’s polar ice shelves are “crumbling at an alarming pace.” In other good news: sea levels will rise much faster than we thought.

It’s possibly the lamest thing ever done in space: yesterday, astronauts spent some time updating their antivirus software.

It was the fake mustaches that tipped them off. Up to 10 percent of Near Earth Objects are comets impersonating asteroids - and new research aims to unmask them.

It’s really, really big: a black hole as big as 50 billion suns.

The ocean has its own lakes – called meddies – and scientists are using oil industry tech to study them.


Science Doesn’t Sleep (8.26.08)

No 296!.....I am NOT a Number..lol..:O)
Creative Commons License photo credit: law_keven

So here’s what went down after you logged off.

According to new analysis of satellite imagery, cows tend to face “moo North” – indicating that they somehow sense Earth’s magnetism.

The goblin shark is so strange-looking – and you can check it out in this video from Japan.

Victory for the caveman! According to new research, Neanderthal technology was no less advanced than early human technology. (So, they didn’t go extinct because they were dumb) Also smarter than you think: goldfish.

Now you can decide for yourself whether CERN is about to destroy the Earth: they’ve published all the techincal details online, at the Journal of Instrumentation, and it’s free to read without a subscription.

What happens when our technology becomes smarter than we are?