Whales Do Echolocate – How Does Echolocation Work For Whales?

Question

Last Updated on May 7, 2021 by Ephraim Iyodo

Sound waves travel through water at about 1.5 km/sec (0.9 miles/sec), which is 4.5 times faster than sound traveling through air.

Whales depend on sounds in water to communicate, navigate and hunt underwater, this therefore is echolocation.

Echolocation in whales is mainly done in order to communicate and navigate, these two function enable them to hunt for prey.

Sound And Communication In Water – Whales

echolocation in whales

Whale Echolocating

Whales make whistling sounds, echolocation clicks, pulse sounds, low-frequency pops and claps of their jaws.

Whales make these sounds by moving air between the nasal sacs in their sniffing area(blowhole region).

A complex of tissues in the nasal region of the toothed whale, called the dorsal bursa, is the site of sound production.

This complex includes “phonic lips” , they are structures that protrude into the nasal passage.

Whales make at least some sounds by releasing air through the nasal passage and past the lips: the surrounding tissues vibrate to produce sound.

Letting air out is not necessary to produce sound.

Killer Whales do let air out of their blowhole during some vocalizations, but these trails and clouds of bubbles are probably a visual demonstration.

Killer whales use whistling to communicate at close range, or in private, and to coordinate behavioral interactions between animals.

The whistle has a high frequency, a high degree of directionality and a strong modulation, so it is not transmitted far underwater.

The frequency of orcas whistles ranges from 0.5 to 40 kHz, with peak energy at 6-12 kHz.

Killer whales use whistling to communicate at close range, or in private, and to coordinate behavioral interactions between animals.

The whistle has a high frequency, a high degree of directionality and a strong modulation, so it is not transmitted far underwater.

The frequency of orcas whistles ranges from 0.5 to 40 kHz, with peak energy at 6-12 kHz.

Pulsed calls are the most common vocalization of killer whales.

Killer whales make these calls at frequencies of about 0.5 to 25 kHz, with peak energy at 1 to 6 kHz.

Calls that sound the same over and over again are called stereotypical. All stereotypical sounds of an orca make up its repertoire.

Individuals of any particular pack have the same repertoire of sounds, a vocalization system called a dialect.

Although scientists note that there is some structure to these sounds, a dialect is not the same as a language.

Analysis of orca call patterns has shown significant differences between the dialects of different herds.
Orcas that are paired with each other may share call patterns. Orcas that share call signs are called a clan.

Cetaceans may share a certain level of their repertoire with other cetaceans, while other parts of their repertoire are unique. The more similar they are, the greater the degree of kinship between them and the individuals.

No two individuals have a common repertoire. Thus, each group has its own unique dialect. In fact, the vocal repertoire of each group differs so much that scientists can identify the groups by the sounds they make.

Killer whales, separated by great geographic distances, have completely different dialects.

Analysis of Icelandic and Norwegian killer whales showed that the Icelandic population makes 24 different sounds, and Norwegian whales make 23 different sounds, but the two populations do not have a single sound in common.

Whale And Echolocation

The whale echolocates by making clicks and then receiving and interpreting the resulting echo.

The echolocating whale uses its lips to emit directional broadband clicks in a rapid sequence called a “train.

Each click lasts less than one millisecond. One study of resident whales measured broadband, bimodal echolocation clicks that typically exhibited low frequency peaks ranging from 20 to 30 kHz and high frequency peaks ranging from 40 to 60 kHz.

The click trains pass through the melon (a rounded area of the whale’s forehead), which is composed of lipids (fats). The melon acts as an acoustic lens, focusing these sound waves into a beam that projects forward into the water in front of the whale.

The sound waves produced by the whale are reflected from objects in the water, and their echoes return to the whale.

The main places where sound is received are the fat-filled cavities of the lower jaw bones. Sounds are received and transmitted through the lower jaw to the middle ear, inner ear, and then to the auditory centers in the brain via the auditory nerve.

Killer whales often have to navigate in the absence of light or good visibility.

Therefore, hearing is extremely important to them. Killer whales’ primary sensory system is the auditory system.

It is a highly developed system that includes the biological ability to sonar or echolocation. Echolocation helps killer whales determine the size, shape, structure, composition, speed and direction of an object.

Whales And Bats

Echolocation systems are one of nature’s extremely successful specializations.

About 80 species of toothed whales use this technique. But why do animals like whales and even bats develop the same technique? The reason cannot be found in kinship, since bats and whales are no closer to each other than all other mammals that evolved from the same terrestrial vertebrates 200 million years ago.

The answer lies in convergent evolution — when almost identical features or developments happen in different species. Through evolution both bats and toothed whales have developed the same functional characteristics.

Our research has shown that the sounds of bats and toothed whales are remarkably similar.

There are two reasons for this: Firstly, the ears of all mammals are developed quite similarly, and secondly and most surprisingly, the conflicting physical conditions in air and water along with the differences in animal size offset the differences you would expect in sound frequency,” says Professor Annemarie Surlykke from the University of Southern Denmark.

Since a bat is much smaller than a whale and its prey is correspondingly smaller, it needs to produce sounds of very high frequency to achieve the same ability to detect the direction and size of its prey.

However, the effect of the higher frequency will be partly offset by the fact that sound propagates five times slower, and therefore sound waves in air are five times shorter than in water.

The researchers concluded that bats and toothed whales produce echolocation signals in the same frequency range, from 10 to 200 kHz.

The advantage of operating in water rather than air is that the “acoustic field of view” of a whale is six times larger than that of a bat.

The “acoustic field of view” is the area in which an animal can “see” its surroundings through echolocation. A sperm whale can echolocate its prey up to 500 meters away, while a bat’s echolocation distance is only 2-10 meters.

Bats fly fast and travel about one echolocation distance per second. Therefore, they often spend less than a second detecting and catching their prey.

Whales move slower and have a much longer echolocation distance. Thus, they have more time to receive information from the echo, and they have time to choose their prey more carefully.

This may explain why bats are not particularly choosy about their prey, while baleen whales are much more selective in their food choices. Bats simply don’t have time to choose – they prefer fast food!

In the last part of the hunting phase, when they approach their prey, both toothed whales and bats make a series of buzzing sounds: weak and short beeps at very short intervals – similar to a strobe light.

It is a very complex mechanism that scientists have not yet fully understood. Animals control very carefully when they make sounds and when they listen for echoes-and adjust it precisely to their speed and the speed of their prey.

If they make buzzing sounds too fast, they don’t have time to listen for the echo. If they do it too slowly, they risk hitting obstacles on the fly.

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Ephraim Iyodo 1 month 0 Answers 348 views -1

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