Shark Week: Tiger Sharks May Yo-Yo Dive When Feeding

More

To better understand tiger sharks' behavior, researchers attached accelerometers and digital cameras to the dorsal fins of four sharks

TigerSharks-WikiC-Post.jpg

One of the ocean's top predators seems to maneuver through multiple sea columns to enhance hunting rather than save energy, according to recent research.

Tiger sharks (Galeocerdo cuvier) navigate vertically through water columns in what's called "yo-yo diving" -- or repeatedly descending into the ocean's depths and actively swimming upward in the same area.

Before the data were collected, it was thought yo-yo diving in other fish might serve a purpose in conserving energy, perhaps assisting in regulating body temperatures or contributing to food foraging efforts. Energy conservation, in particular, makes sense at first glance since sharks can expend little energy by gliding during their descent into deeper waters and swimming back up.

But, as the study concludes, this wasn't the case.

BLOG: Tiger Shark Feeding Frenzy Captured on Video

To better understand tiger sharks' diving behavior, researchers attached accelerometers and digital still cameras to the dorsal fins of four wild sharks for a total of 24 hours off the coast of Hawaii island. The equipment recorded the sharks' acceleration and angles of movement, which detailed their speeds and whether the animal traveled horizontally, vertically or a variation of both.

During the time scientists observed the tiger sharks, they discovered that all the animals practiced yo-yo diving. Though the sharks accelerated less while descending downward through the water columns, they didn't glide as predicted.

In fact, the sharks still accelerated while traveling downward through water columns -- a trend that coincided with the presence of potential prey items in photos recovered from the underwater cameras on the sharks' dorsal fins.

Instead, the team concluded that sharks in the small sample may deploy yo-yo diving as a foraging strategy to access food items at different depths.

BLOG: Human Body Parts Found in Tiger Shark's Stomach

oceanbug.jpg

Tiger sharks thrive on a variety of foods, including fish, shellfish, crabs, sea birds and mammals. The truth is they're not picky eaters, with one case in which authorities found a chicken coop in a tiger shark's stomach.

Though the observations suggest energy conservation might not give rise to yo-yo diving behavior in tiger sharks, it's important to keep in mind that the experiment sampled a small number of sharks in one area and there might be other factors at play.

It's likely researchers will need to find a stronger link between diving behavior and prey consumption to support their conclusions.

MORE SHARK WEEK COVERAGE:

Image: Wikimedia Commons.

Jump to comments
Presented by

Marianne English is a freelance writer currently pursuing a pro-track master’s degree at the University of Wisconsin-Madison with a specialty in science and health writing.

Get Today's Top Stories in Your Inbox (preview)

The Time JFK Called the Air Force to Complain About a 'Silly Bastard'

51 years ago, President John F. Kennedy made a very angry phone call.


Elsewhere on the web

Join the Discussion

After you comment, click Post. If you’re not already logged in you will be asked to log in or register. blog comments powered by Disqus

Video

Adventures in Legal Weed

Colorado is now well into its first year as the first state to legalize recreational marijuana. How's it going? James Hamblin visits Aspen.

Video

What Makes a Story Great?

The storytellers behind House of CardsandThis American Life reflect on the creative process.

Video

Tracing Sriracha's Origin to Thailand

Ever wonder how the wildly popular hot sauce got its name? It all started in Si Racha.

Video

Where Confiscated Wildlife Ends Up

A government facility outside of Denver houses more than a million products of the illegal wildlife trade, from tigers and bears to bald eagles.

Video

Is Wine Healthy?

James Hamblin prepares to impress his date with knowledge about the health benefits of wine.

Video

The World's Largest Balloon Festival

Nine days, more than 700 balloons, and a whole lot of hot air

Writers

Up
Down

More in Technology

Just In