Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientist discovers some mammals can smell objects under water

21.12.2006
A Vanderbilt researcher has discovered that some stealthy mammals have been doing something heretofore thought impossible – using the sense of smell under water.

The results of the research by Vanderbilt’s Kenneth Catania, assistant professor of biology, were reported Dec. 21 in the science journal Nature. He became curious when he observed that a mole he was studying blew a lot of bubbles while swimming.

“This came as a total surprise because the common wisdom is that mammals can’t smell underwater,’ said Catania, who earlier this year won a $500,000 “genius grant” from the John D. and Catherine T. MacArthur Foundation.

“When mammals adapt to living in water, their sense of smell usually degenerates. The primary example is the cetaceans – whales and dolphins – many of which have lost their sense of smell.”

... more about:
»Catania »Sniffing »TRAIL »mammal »semi-aquatic »star-nosed

Catania devised a series of experiments to determine whether the star-nosed mole and another small, semi-aquatic mammal - the water shrew - can smell objects underwater. Using a high-speed camera, he discovered how they do it.

After observing that the moles were blowing bubbles out of their nostrils and then sucking them right back in, he determined they were exhaling and inhaling the bubbles rapidly, between five and 10 times per second. That is about the same rate as the sniffing behavior of comparably sized land mammals, like rats and mice. “Rats and mice don’t sniff the way we do,” Catania said. “They push air ‘out-in out-in’ in a fashion strikingly similar to what the star-nosed mole is doing, except that it is doing it under water.”

Catania mounted a high-speed video camera so that it pointed up through the bottom of a glass tank. Then he stuck various objects on the bottom of the tank – pieces of earthworm, small fish, insect cuticle and blobs of wax and silicon – and observed the moles’ behavior. He saw that, when the moles approached one of these targets, they would blow bubbles that came into contact with the target’s surface and then were sucked back into the nostrils.

“Because the olfactory nerves in the nose are covered with mucous, odorant molecules are all water soluble,” Catania said. “So, when these bubbles come into contact with an object, it is almost inevitable that odorant molecules will mix with the air and be drawn into the nose when the bubble is inhaled.”

Just because the moles are getting whiffs of interesting odors underwater doesn’t necessarily mean they smell them.

So Catania devised some additional tests.

One of the complicating factors was the star-nosed mole’s unusual nose, which is ringed by a star-shaped set of fleshy appendages. It uses its star like a super-sensitive set of fingers to identify objects it encounters while burrowing and swimming. So, at the same time it is sniffing at an object it is also fingering it with its star.

To determine if the mole can identify edible objects by sniffing alone, Catania created underwater scent trails leading to food and recorded how well the moles could follow them. To keep the moles from using their tactile star, he put a grid-work between the animals and the scent trails. The openings in the grid were too small for the star appendages to squeeze through but large enough so the air bubbles could pass without difficulty.

These trials demonstrated that the moles could follow the scent trail by sniffing alone (without the tactile star). Five moles were tested on earthworm scent trails and followed the trail to its reward with accuracies ranging from 75 percent to 100 percent accuracy. Two moles were tested with fish scent trails and followed them with 85 percent and 100 percent accuracy.

When the grid was replaced with a screen with openings too small for the air bubbles to pass through, however, the moles’ performance dropped down to the level of chance – the same as their performance with no-scent trails.

In order to see if this capability was limited to the star-nosed mole or if other small semi-aquatic mammals also have it, Catania captured some water shrews and began testing them. He found that they also exhibit this underwater sniffing behavior and can use it to follow underwater scent trails.

“Now, the question is, ‘What other semi-aquatic mammals do this?’” Catania said. “Do animals like otters and seals do anything similar? Or is there a size limit and it only works for smaller mammals?”

He hopes that publication of his paper will encourage researchers who are studying all kinds of semi-aquatic animals to take a closer look at how they are using their noses underwater.

The research was funded by a Faculty Early Career Development award from the National Science Foundation.

David F. Salisbury | Vanderbilt University
Further information:
http://www.vanderbilt.edu

Further reports about: Catania Sniffing TRAIL mammal semi-aquatic star-nosed

More articles from Life Sciences:

nachricht New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences

nachricht The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>