Whale Echo-location and Song
Toothed Whales Use Sonar and Communicate
Some of the loudest animal noises are used by whales to find food and to keep in touch over long distances.
All whales are capable of making sounds, and maybe of ‘singing’, but only the toothed whales can use sonar.
Whale Song
Low frequency sound carries very well through water, and some whales are thought to be able to generate noises that can travel for hundreds (maybe thousands) of miles.
- Blue Whales can make loud (155-188db) sounds of low frequency (10-40Hz) which can travel huge distances (Blue Whale Song – speeded up ten times). The sounds are probably made so that these, largely solitary whales can maintain contact with one-another.
- Humpbacks make much more complex sounds, almost certainly part of their courtship (song, again X10).
- Dolphins emit whistles, clicks, and pulses of sound. Some of these are for echo-location, but others are certainly used for some sort of communication between individuals. It is even thought that individual dolphins might even have their own name (some special squeak) – so that one individual might be able to communicate another, after shouting out the name!
- Each clan of Killer Whales has its own dialect, and this helps keep them together. It is even suggested that they might be able to plan their hunting strategy by chatting about it (song – natural speed). When they hunt fish they make all sorts of noises and echo-locate, but when they are after other whales the keep quiet (all whales have good hearing).
- Sperm Whales make the loudest noise of any animal (163-223db), usually as single clicks. These might be used for echo-location, but it has been suggested that the enormous head might focus the sound onto their squid prey and be used to stun them.
- Belugas (sometimes called sea canaries) are the most garrulous of all – with squeaks, squawks, whistles, clicks and bell-like sounds. They echo-locate superbly, but also seem to communicate and court one-another (listen to their calls during this video).
Echo-location or Sonar
Toothed whales are all able to find their way about underwater using a form of sonar (echo-location). They have lip-like structures near the blowhole, and the sounds are reflected forwards off the dish-shaped front of the skull. These sounds are then amplified and focussed through the ‘melon’ (the rounded blob on the head) and then stream out in front of the whale. Reflected sounds are picked up by the lower jaw and passed to the ear. The ears are shielded from the source of the noise production, and each ear hears independently. The information they can glean from these reflections allows them to ‘see’ through murky water and in the dark. They can even see into the sediment on the sea-bed, and probably into one-another (rather as we see inside people using sound-scans). Whale echo-location is not very well understood – but that is not surprising when you remember that we have only been using sonar for fifty or so years, and they have had thirty million years of experience!
Main reference: ‘Whales, dolphins & porpoises’ by Mark Carwardine et al., 1998.
Other articles by John Blatchford
click on images below to enlarge
