Birds depend heavily on their sharp hearing to locate prey and recognize the calls of other birds. Their hearing is actually more refined than that of humans, allowing them to perceive sounds in greater detail. Interestingly, birds do not have the external ear structures that humans possess—so how do they manage to hear so well?
Anatomy of birds ears
While birds do have ears, their design differs significantly from ours. Both birds and humans share an inner and middle ear, but birds lack the visible outer ear found in humans. Instead, each side of a bird’s head has a funnel-like opening that serves as the outer ear. These openings, typically located just behind and slightly below the eyes, are shielded by small, soft feathers called auriculars, which help protect the delicate ear area.
The position of a bird’s head also contributes to its remarkable hearing abilities. Research has shown that sounds reach each side of a bird’s head at slightly different frequencies. Depending on where the sound comes from, it will strike the left and right eardrums differently. The bird’s brain interprets these variations in frequency to pinpoint the exact location of the sound source.
Owls – case study
Owls are a well-known example of birds with extraordinary hearing. Their ability to detect prey in complete darkness comes partly from the uneven placement of their ear openings—one is positioned higher or lower than the other. This asymmetry causes sounds to reach each ear at slightly different times—sometimes differing by as little as 30 millionths of a second—allowing the owl to determine direction with incredible precision. Other birds of prey use small flaps near their ears to detect whether a sound originates from above or below them.
Although some owl species appear to have ears on top of their heads, those are actually just feather tufts. These tufts are controlled by small muscles beneath the skin and serve no function in hearing.
Why birds don’t have teeth ?
Early scientists believed that the absence of teeth in birds was an evolutionary adaptation that helped them catch prey—such as worms, insects, and small vertebrates—and eat seeds or nuts more efficiently. Without teeth, their beaks were less cumbersome, and the reduced weight may have made flight easier as well.
However, newer studies have challenged these older ideas and offered a different perspective. It turns out that developing teeth takes a long time during embryonic growth. Based on research comparing birds to their dinosaur ancestors, forming teeth could have consumed up to 60 percent of a bird embryo’s incubation period. By losing teeth altogether, early birds may have been able to hatch faster, reducing the time they remained defenseless inside their eggs. Today, many bird species hatch within just a few days or weeks, whereas dinosaurs often stayed in their eggs for several months before emerging.