Physical Features
An animal's physical body structure determines its degree of hearing accuracy. For instance, a species' ability to detect the location of a sound comes from the difference between the sound wave's timing and intensity. Animals whose ears are close together tend to experience less degrees of accuracy in determining sound location. In mammals, smaller heads can lead to less sensitivity when it comes to determining the horizontal and vertical location of a sound's origin.
Auditory Organs
The inner ears of most animal species contain hair cells that connect to auditory organs. These organs are responsible for sorting and processing different sound frequencies. An animal's auditory organs select frequency ranges depending upon the number and type. For example, most fish and other amphibians have two auditory organs. One responds to lower ranges while the other gravitates towards higher levels. The capability of these organs to select certain frequency ranges directly influences hearing accuracy in animals.
Cognitive Skills
The way that an animal's brain processes sound frequencies affects hearing accuracy. The brain detects slight differences in the sounds heard in the environment. Cognitive functions take apart sound frequencies to determine what type they are and where they are coming from. Difficult or complex sounds require more brain activity, especially when there are two tones in a frequency range that closely resemble each other. Some species also find it more difficult to process slight differences in frequency when exposed to multiple sound sources. Other species process differences in sound locations by hearing louder sounds in one ear. For example, the barn owl hears the same volume in both ears for sounds originating from eye level. In contrast, one ear hears a higher pitched sound for frequencies that come from a location above the owl's position.
Adaptation
Some animal species learn to rely on a keen sense of hearing due to their environments or lack of proficiency in one of the other vital senses, such as sight. Animals that spend more of their waking hours during the night tend to develop a heightened sensitivity to sound. They use their ability to detect sounds accurately at night to navigate through the darkness. Some species even detect very low or high frequency sounds as a survival and hunting mechanism.