Unexpected Look of the Ears of Crows

It’s nice to see this happy crow.

The footage below, posted by trained crow handler and animal volunteer Olly Peckar, shows a very happy crow getting some gentle pets while Olly exposes its ear from underneath its feathers.

Let’s just say we weren’t expecting something that… big?

happy-crow

Avian ears lack the external pinnae that our human ears have, but they do have an internal cochlea like us – only it’s not shaped like a spiral, it’s mostly straight.

Birds are known for their keen sense of hearing, and also their ability to figure out if a sound is coming from above, below, behind, or next to them.

Wherever the source is situated, somehow a bird is able to localise it, and all without an external ear structure like mammals have.

Scientists have only recently figured out how they do this, and it turns out that in lieu of an external ear, birds use their entire heads to detect the location of incoming sound waves.

“Because birds have no external ears, it has long been believed that they are unable to differentiate between sounds coming from different elevations,” Hans A. Schnyder from the Technische Universität München in Germany explained.

“But a female blackbird should be able to locate her chosen mate even if the source of the serenade is above her.”

Back in 2014, Schnyder and his team investigated the hearing ability of three bird species – crow, duck, and chicken.

They found that the birds were able to identify sounds from different elevation angles thanks to their slightly oval-shaped heads, which appear to process sound waves in a similar way to the external ears of mammals.

Turns out, birds receive different sounds at different volumes, and this helps them figure out the general direction of the source.

Sounds originating from the same side as the ear hit the eardrum at a certain frequency, but once they passed through the head and reached the eardrum on the other side, they would register at a different frequency.

“The eardrum differences allowed the bird’s brain to determine whether the sound was coming from above or below or at level with the bird,” CBC News explains. “That meant the bird’s head was able to reflect, absorb or diffract the sounds.”

Experimental Device Could Help People Suffering from Tinnitus

Tinnitus impairs the livelihoods of millions of people, so it’s good that there’s scientific progress in developing treatment for it.

Millions of Americans hear ringing in their ears — a condition called tinnitus — and new research shows an experimental device could help quiet the phantom sounds by targeting unruly nerve activity in the brain.

In a new study in Science Translational Medicine, a team from the University of Michigan reports the results of the first animal tests and clinical trial of the approach, including data from 20 human tinnitus patients.

Based on years of scientific research into the root causes of the condition, the device uses precisely timed sounds and weak electrical pulses that activate touch-sensitive nerves, both aimed at steering damaged nerve cells back to normal activity.

Human participants reported that after four weeks of daily use of the device, the loudness of phantom sounds decreased, and their tinnitus-related quality of life improved. A sham “treatment” using just sounds did not produce such effects.

[…]

“The brain, and specifically the region of the brainstem called the dorsal cochlear nucleus, is the root of tinnitus,” said Susan Shore, the U-M Medical School professor who leads the research team. “When the main neurons in this region, called fusiform cells, become hyperactive and synchronize with one another, the phantom signal is transmitted into other centers where perception occurs.

“If we can stop these signals, we can stop tinnitus. That is what our approach attempts to do, and we’re encouraged by these initial parallel results in animals and humans.”