Physics explain how Bats are able to move mile to mile at dark night

Image Credit :www.clayton.edu/

In the early science it was seemed that the bats are blind and they could not see at all i.e. they are blind. And because of this they could not move in day time. But this was just logic depend upon early science.But amazing fact is that when researcher and birds lover investigate a lot and they comes to conclude that  bats can move very well in night and they are always move in night to collect foods. They can navigate object over a mile.  This fact was the challenging to the scientist for many centuries. But science develops and research worker get a collective conclusion that saying “blind as a bat”, simply isn’t correct. The truth is that all 1,100 bat species can see and often their vision is pretty good, although not as excellent as many other night-hunting animals.
Fast fact: Groups of Bats depending vision and Hearing:There are two main groups of bats, which are believed to have evolved independently of each other, but both from a common ancestor. The first group, Megachiroptera, is mostly medium-sized or large bats who eat fruits, nectar, and sometimes small animals or fish. These species have pronounced visual centers and big eyes as they use senses of vision and smell to capture their prey. For example, Flying Foxes are able not only to see well during daylight, but also can see in color. They actually rely on their daylight vision and cannot fly during moonless nights.The second group, Microchiroptera or “micro bats”, are smaller in size and mostly eat insects. These species (about 70% of all bats) use echolocation to navigate and identify the food. There are two types of photoreceptor cells in the retinas of mammals: the cones, for daylight and color vision, and the rods, for night vision. Until recently, micro bats that are nocturnal were believed to have only rods. However, now scientists have proven that despite their poorly developed small eyes, these bats still can see during the day. Even considering mostly nocturnal lifestyle of these bats, they have to be sensitive to changing light levels because this is how they sense when it is night to start hunting. Moreover, vision is used by micro bats to navigate over long distances, beyond the range of echolocation.

Image credit: www.britanica.com

Mechanism of Seeing: Reference: 1. An interesting fact that bats and other animals can view everything and they can move mile to mile distance at night.2. A mother bat can locate her pup by its scent and sound out of millions in a roost.3. They can navigate an object over a mile.4. There are about 800 different species of bats that use different patterns of frequencies. Specialty in structure of Bats Some bats make sound and send out by their noses but, most send different sounds through their mouth. Bats have very sensitive ears to identify different kind of sounds. Although bats have good eyesight, they depend on the echolocation. Bats give off pulses at very high frequencies that are not audible to humans, at an impressive rate of 200 pulses per second ( Ultrasonic sound that are use in sonar system). Human hearing ranges from approximately 20 Hz (cycles per second) to 15 to 20 kHz (1000 Hz) depending on age. In comparison, some bats can hear sounds up to 110 kHz in frequency and human being can not able to detect this sound. By emitting a series of Individual bat species echolocate within specific frequency ranges that suit their environment and prey types. This means that we can identify many bats simply by listening to their listening to their calls with bat detectors.It is often quite loud ultrasounds that either sweep from a high to low frequency or vary around a frequency; bats can distinguish objects and their insect prey and therefore avoid the object or catch the insect. They can avoid obstacles no wider than a piece of thread, identify the size of objects, and capture flying insects using this method. There are about 800 different species of bats that use different patterns of frequencies. This allows scientist the ability to identify various types of bats in dark places, such as caves. We can able to see any object due to reflection of visible light with the object. Our nervous system can analyze the reflected light or signal (visible) to identify the object. If there is no light we cannot able to see anything. We cannot sense the EM wave except visible light. As example Arctic caribou can see ultraviolet light, Cat's' eyes, to see in the dark that is it can sense Infrared light. Bats of Megachiroptera group can able to see due to their eye are as bigger as getting the reflected visible light. Echolocation: Finding out location by sending and receiving reflected sound Major type of Bats of Microchiroptera group uses the echolocation method to move mile to mile instead of vision mechanism. To understand this mechanism we can imagine the working of a radar or sonar. Both are used to detect the location of special body that’s bouncing signal is calibrated. Hearing is closely related with the mechanism of seeing or the mechanism of radar and sonar. These all can collect and analyze reflected waves of energy. Vision processes light waves as they travel from their source, bounce off surfaces throughout the environment and enter the eyes. Similarly, the auditory system processes sound waves as they travel from their source, bounce off surfaces and enter the ears. Both systems can extract all of information about the environment by interpreting the complex patterns of reflected energy that they receive. In the case of sound, these waves of reflected energy are called "echoes". Echoes and other sounds can convey spatial information that is comparable in many respects to that conveyed by light. Depending the sense of echoes due to various type of object surface ,a blind person can receive very complex, detailed, and specific information from distances far beyond the reach of the longest cane or arm. Echoes make information available about the nature and arrangement of objects and environmental features such as overhangs, walls, doorways and recesses, poles, ascending curbs and steps, planter boxes, pedestrians, fire hydrants, parked or moving vehicles, trees and other foliage, and much more. Echoes can give detailed information about location (where objects are), dimension (how big they are and their general shape), and density (how solid they are). Location is generally broken down into distance from the observer and direction (left/right, front/back, high/low). Dimension refers to the object's height (tall or short) and breadth (wide or narrow). In the above image yellow curve represent the throwing ultrasonic sound ( it can not be able to hear by us) and the gray curves are the reflected sound (echos). By analyzing this a bat can able to identify the insect. By understanding the interrelationships of these qualities, much can be perceived about the nature of an object or multiple objects. For example, an object that is tall and narrow may be recognized quickly as a pole. An object that is tall and narrow near the bottom while broad near the top would be a tree. Something that is tall and very broad registers as a wall or building. Something that is broad and tall in the middle, while being shorter at either end may be identified as a parked car. An object that is low and broad may be a planter, retaining wall, or curb. And finally, something that starts out close and very low but recedes into the distance as it gets higher is a set of steps. Density refers to the solidity of the object (solid/sparse, hard/soft). Awareness of density adds richness and complexity to one's avail Bats are not blind; in fact they can see almost as well as humans. But to fly around and hunt for insects in the dark, they use a remarkable high frequency system called echolocation.. For instance, an object that is low and solid may be recognized as a table, while something low and sparse sounds like a bush; but an object that is tall and broad and very sparse is probably a fence. Benefit to the scientist There are about 800 different species of bats that use different patterns of frequencies. This allows scientist the ability to identify various types of bats in dark places, such as caves. 1.www.wikipedia.org2.www.clayton.edu/faculty/sburnett/Bat-Visits/How-do-bats-navigate 3.http://www.dailymail.co.uk/femail/article-2725762/Animals-super-powers-Sonar-hearing-infrared-vision-lightning-reflexes-A-new-BBC-reveals-amazing-abilities-help-animals-survive.html