Rescued Dolphins Tested For Hearing Loss

Researchers at the University of Florida have been working with rescued dolphins to help determine why they became beached or entangled in fishing nets despite their highly advanced sonar abilities.

They found almost 60 percent of stranded bottlenose dolphins now recovering in Florida rescue facilities were severely or profoundly deaf.

“We used the same methods to test the dolphins as is used to measure hearing in human babies,” said the study’s lead researcher, Dr. David Mann of the University of South Florida. “Like human babies, some dolphins are born deaf and can probably survive well with their mothers until weaned, but hunting on their own can be problematic, although some do seem to adapt and manage.”

“The researchers affixed sensors to the creatures’ heads with suction cups, which could detect electrical activity in the brain. They then played a series of tones: If the animals could hear them, the sensors would detect millions of neurons firing to process the sound” reports the Washington Post.

Causes of deafness in whales and dolphins are similar to those in humans and range from exposure to chronic noise from busy shipping lanes, disease, trauma and ageing, reports EarthTimes.

Although conservationists might be inclined to blame Naval sonar activities when mass strandings of marine mammals occur around the world, this might not be warranted.

Darlene Ketten, the world foremost expert on marine mammal hearing, reports that fewer than 300 animals have been stranded in association with naval exercises in the last 50 years.

This pales in comparison to the 100,000 and 400,000 animals that are injured and killed as a result of being caught up as bycatch in fishing nets.

Mann and his research team concluded that it’s possible that animals with damaged hearing might be more likely to strand if they cannot orientate themselves properly.

As a result, Mann recommends that the hearing of all cetaceans in rehabilitation be tested to find out if they’re deaf, and to help determine whether or not they will be able to survive in the wild.

The high cost of marine mammal rehabilitation could prevent scientists from spending too much time working with dolphins and other creatures unlikely to survive because of hearing loss.

Image Credit: Flickr - Skyfisher

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161 comments

Yvonne Fast
Yvonne F.4 years ago

Poor things! I hope they will be cared well fore!

Carole R.
Carole R.4 years ago

These deaf dolphons deserve to live. They can survive in the pod and I'm sure they adjust to it.

Sumit jamadar
Sumit jamadar5 years ago

THANKS

John Gregoire
John Gregoire5 years ago

No animal should be forced into captivity. While I abhor zoos and the like, I very strongly believe that we can and should care for wildlife with injuries. These dolphins that can't hear, birds that can't hunt would be perfect for care in a place where people can learn.

Lauren J.
Lauren J.5 years ago

Aw pour dolphins...

Ge ARACELI
Past Member 5 years ago

It is EXCELLENCE OF THE HUMAN CONDITION to CARE FOR each other FOREMOST... and to NOT FORSAKE THE LIVES OF CREATURES OF Our EARTH AND OR OF Our UNIVERSE...

the dolphins
they definately DESERVE the CARE AND APPRECIATION!
WE NEED TO CARE FOR Our DISABLED LIKEWISE...
NO MATTER THE CONDITION OF DISABILITY...
WE OWE each other
THE CONDITION OF PEACE AND HAPPINESS Both...
and NOT to exist as ONE to endure DURESS
as ONE to endure HARASSMENT
simply due
to being DISABLED and or INJURED in some sense

I LOOK FORWARD TO MORE GOOD WORKS FROM LIVES
that WORK DILIGENTLY FOR Our WILDLIFE ... yes that
AND LABOR WITH INTEGRITY
For Our OWN PEOPLE AS WELL
UNMOVABLE IN ALLOWING PREDATORY TYPES
to bring Our PEOPLE HARM AND OR INJURY
such as I have seen done to DISABLED and or us INJURED!

GOOD STORY as ARE ALL OF THOSE
with a SWEETENED EFFECT OF GOOD WILL IN THEM!

thank you for the post

G S.
v s.5 years ago

I think it would be wrong to euthanize them. They stated that the deaf or partially deaf dolphins were able to survive with other members of the pod. I think they should let them go & let them live our their lives before they kill them. Yes, that what euthanizing them would be in this case. Noone should kill an animal because they cant care for it. Nature needs to be allowed to be nature. God made us stewards of the animals, but sometimes interfering and then taking it upon ourselves to kill them is just as bad as throwing them into a net. These people need to understand that each & every creature has a purpose and they need to let it go if they cant afford to take care of it. All the money we give is not going to change that unfortunately. IF so, I would like some proof from them.As soon as yesterday!

G S.
v s.5 years ago

I think it would be wrong to euthanize them. They stated that the deaf or partially deaf dolphins were able to survive with other members of the pod. I think they should let them go & let them live our their lives before they kill them. Yes, that what euthanizing them would be in this case. Noone should kill an animal because they cant care for it. Nature needs to be allowed to be nature. God made us stewards of the animals, but sometimes interfering and then taking it upon ourselves to kill them is just as bad as throwing them into a net. These people need to understand that each & every creature has a purpose and they need to let it go if they cant afford to take care of it. All the money we give is not going to change that unfortunately. IF so, I would like some proof from them.As soon as yesterday!

Christina A.
Christina Aitken5 years ago

Dolphins are fantastic creatures, I myself have been swimming with them and they are magical. I watched while they helped a severely disabled children swam with them too, magical moment, we should protect and care for these wonderful creatures without a doubt.

Suzanne Hall
Suzanne Hall5 years ago

If we can help them survive, I'm all for it. But as stated in the article, and previous comments, money is the bottom line. I donate quite a bit to charities, all animal welfare organizations, and I'll have to see if I can't add just one more...