Blog Tags: Whales
Bats and toothed whales share the ability to squeak and click their way to prey. And now two new studies in this week’s journal Current Biology reveal that their echolocation, which evolved independently in the two groups, has a similar underlying molecular mechanism.
There are plenty of examples of evolutionary convergence, such as the tusks of elephants and walruses, or the bioluminescence of fireflies and jellyfish.
But it’s highly unusual for convergence to occur at the molecular level. Turns out the inner ear hair cells of both the bottlenose dolphin (a toothed whale) and 10 species of bats contain a protein called prestin, which plays an important role in echolocation.
But not all echolocaters are created equal. Because the speed of sound in water is five times that in air, dolphins can use echolocation for more than 100 meters. Bats can only do so for a few meters.
(Hat tip to Monterey Bay’s Sea Notes blog for this story.)
The researchers discovered that the two groups, which they have creatively dubbed "Type 1" and "Type 2" have different wear on their teeth, suggesting different diets and thus different ecological niches. Then, genetic analysis confirmed that the two types of killer whale belong to different populations.
The scientists compared the findings to how Darwin's finches adapted to fill unique ecological roles.
So what does this mean for the future of the North Atlantic killer whales? If Type 1 and Type 2 become separate species, they would require separate conservation monitoring efforts.
And if that happens, hopefully the powers that be will think of some catchier names for them.
An Australian paleobiologist has made a curious discovery about the origins of baleen whales. Studying the 25-million-year-old fossil of a primitive toothed baleen whale, Mammalodon colliveri, Dr. Erich Fitzgerald hypothesized that the early whale used its tongue and short, blunt snout to suck small prey from sand and mud on the seafloor. Yummy.
Fitzgerald’s work supports Darwin's notion that some of the earliest baleen whales may have been mudsuckers before they were filter-feeders.
And apparently the three-meter-long Mammalodon was actually a dwarf, though its name brings to mind its relative, the blue whale -- the largest animall in the history of the world.
As Dr. Fitzgerald said, “Clearly the seas off southern Australia were a cradle for the evolution of a variety of tiny, weird whales that seem to have lived nowhere else.”
Some consider the great white shark to be the fiercest predator in the ocean. Now Free Willy is giving the species a run for its money. Orca whales' diet traditionally includes fish, squid, birds, seals, and other whales. Now some are adding Jaws to the menu.
Several populations of orca whales have learned how to attack sharks, including the great white, with various techniques, including what some scientists are calling the “karate chop.” To execute this sly move, the orca drives the shark to the surface, then comes down on top of the shark and turns it upside down, at which point it enters a paralyzed state. In fact, all the attack methods ultimately end with the shark on its back.
If you want more, watch this recent video of one such showdown.
Here at Whale Wednesday, we generally talk about the amazing life of whales… while they are alive. But like everything in nature, cetaceans pass on. And good thing, too, if you are a boneworm.
These strange, tiny creatures feast on the bones of mammal carcasses on the sea floor. Bobbing along as microscopic larvae until they come in contact with a whale or elephant seal, they then latch on, sending root-like structures into the bones and feathery arms into the water. The bacteria in these roots break down bone protein, while the feathery appendages draw in oxygen. And that’s not the strangest part.
All boneworms start off male, but as they sexually mature, become female. However, if a male larvae lands on a female boneworm, he will become a male worm, though remain microscopic in size. He will then go on to fertilize the females eggs, which will result in all-male larvae. And the cycle begins again.
Space is often touted as the final frontier, but the depths of the oceans hold much more mystery… and bone eating worms.
Since I missed Whale Wednesday yesterday, I'm making up for it today with an update on an adorable Canadian cetacean.
As you may or may not recall, a beluga whale was born at the Vancouver Aquarium this summer. Now she needs a name, and the aquarium is asking for submissions. Here's the rub: the name must be from the Inuit language, Inuktitut, reflecting the beluga's Arctic origins. So that means no "Britney" or "Bathsheba" submissions, people.
I just submitted "illaqtuq" which, I just learned, means "laugh." Belugas have that great high-pitched twitter, after all. And it could be shortened to "Illa." Pretty good, huh?
Grand prize is an encounter with a beluga, and you can submit until Nov. 22.
It's been a while since we started the Whale Wednesday weekly feature, and I don't think beaked whales have ever gotten their day in the spotlight. Today's the day, then, for this mysterious group of cetaceans.
The BBC reports that researchers from Duke University observed the largest group of Arnoux's beaked whales -- around 60 -- ever recorded, off the coast of Antarctica.
Male beaked whales have tusks that emerge from their lower jaws, and in general beaked whales are deep divers. Of the 21 known species of beaked whales, only a few are well-known, including the Cuvier's beaked whale and the Baird's beaked whale.
As one of the Duke scientists, Dr. Ari Friedlander, told BBC, "The Arnoux's were a unique and amazing experience. Hopefully this brief glimpse will spawn further work to better understand the species, their distribution and behaviour, and how these animals fit into the larger ecology of the southern ocean."
In a big victory for our colleagues in Europe, yesterday the EU Court of Justice found Italy in violation of EU law for the country's continued use of driftnets, a fishing gear banned since 2002.
Driftnets, which float freely, sometimes for miles, are a serious threat to cetaceans, sea turtles, sharks and fish in the Mediterranean. Hundreds of thousands of whales and dolphins are killed each year by driftnets.
The day before the decision, Oceana presented its latest report on the use of driftnets in the Mediterranean and stressed that the Court's judgment was an essential step in eradicating the use of the fishing gear.
The Oceana report contains photographs from 2008 of 92 vessels with driftnets on board, 80 percent had already been identified during campaigns in previous years.
Xavier Pastor, Executive Director of Oceana Europe, said, “The judgment is an important milestone in the elimination of driftnets from the Mediterranean. At last we may be moving towards the end of this illegal fishing gear, seven years after the EU banned their use."
Over several years of campaigning in the Mediterranean, Oceana has documented and reported how driftnets, despite the ban, continue to be used, not only in Italy, but also in other areas of the Mediterranean such as Morocco, Turkey, and until recently, France.
Congratulations, Xavier and team!
Don't you hate when you're at a party or restaurant, and even without music on, the room grows louder and louder and louder? Until you can barely hear the person standing right next to you? New research shows that sperm whales have evolved to circumvent this cocktail party conundrum.
According to the scientists, whose work will be presented at the Acoustical Society of America next week, the whales are polite conversationalists -- they make a specific effort to keep their calls from overlapping by changing the intervals between their echolocating clicks.
Perhaps humans can try this. It might go something like this:
"Would you - click - like an hors d'oeuvre - click?"
"Yes, one - click - mushroom puff - click - please."
And in other acoustic findings, researchers have discovered the first known instances of male humpback whales singing to one another, similar to songbirds. Whether the whale songs are macho seduction tunes -- like male birdsongs -- is still unclear.
What is clear is that there's a lot we don't know about what's being said and sung under the sea.
There’s no shortage of blame to go around when it comes to climate change. Individuals are responsible for poor consumer choices; we drive the wrong cars, use the wrong light bulbs, even wash our laundry on the wrong setting. Even the poor dairy cow shares the blame for having the nerve to burp methane emissions. But Bessie isn’t the only creature catching a bad rap. Sperm whales have been criticized for breathing. Yes, breathing. Apparently the carbon dioxide emitted from the roughly 210,000 sperm whales in the Southern Ocean is contributing to global warming, producing in the ballpark of 17 million tons of carbon a year. But new research suggests that we’re missing a very big factor in the calculation. It’s not just what the whales put out, but also what they take in.
- CEO Note: Proposed Puerto Azul Project Puts Belize’s Lighthouse Reef Atoll and Great Blue Hole at Risk Posted Fri, November 21, 2014
- Sea Turtles Can Get the Bends after Capture in Fishing Gear, Says New Study Posted Tue, November 25, 2014
- Ocean Roundup: Dolphins Use Whistles as Names, Conservationists Call for Removal of Queensland Shark Nets, and More Posted Mon, November 24, 2014
- ICCAT Moves to Properly Manage Bluefin Tuna, but Doesn’t Take Action for Sharks and Swordfish Posted Wed, November 26, 2014
- Oceana in Chile Submits Recommendations for Lowering Common Hake Catch Quotas Posted Mon, November 24, 2014