How Does Echolocation Work?
December 9, 2015
Survival instincts are mysterious in a mysterious world.
Echolocation is a unique form of “sight” that’s difficult for human beings to comprehend, in part because of the special skills it requires to perform, but also because of the nature of the underwater kingdom in which its used.
And truthfully, it’s not really “sight” at all.
On land, echolocation used by bats and some species of shrews and rats seems like it’s easier to understand, but underwater, the whales that use echolocation might as well be doing so on the moon.
Echolocation is an animal’s biological sonar. Toothed whales such as orcas and dolphins emit pulses into their environment and then listen to the echo in order to determine distance and identify unique features. Orcas have even been said to possess the ability to identify tiny objects such as pennies resting on the floor of the ocean. The acoustic nature of the water allows sound to travel huge distances and maintain its original clarity.
An ocean of music, indeed.
Maintaining Social Order
At the core of every orca pod is a detailed hierarchy. Families maintain close contact and are rarely out of “earshot”, or, more appropriately underwater, hearing range. Not only is echolocation used to keep track of pod-mates, it’s used as an alert system that can travel rapidly throughout a group of orcas.
“Communication is an essential ingredient of the glue that brings harmony to the orca community.”
That’s a quote direct from Orcalab, an organization that studies the behaviour of coastal BC’s orca population. Clicks, whistles and pulsed calls emitted by orca whales not only allow them to speak to eachother, they create a virtual map for each whale, locating reach member of the pod as though they were drawn out in front of them.
Let’s say a lone seal is “spotted” swimming dangerously close to a group of transient hunters, or at least close enough for one hunter to be alerted of its presence. That orca will in turn alert the rest of the group in order to organize an effective hunting procedure.
In other words, the seal doesn’t stand a chance, even as its oblivious to what’s about to happen.
Echolocation allows orcas the ability to coordinate their hunting efforts in the absence of light or other recognizable features beneath the water. They can sense the movements of their prey as easily as we can see an animal on land from 20 yards away.
Orcas use pulsed calls as their primary form of communication, and it’s been known to differ greatly from pod to pod. It’s in this way that separate clans of orcas are easily identified. Orcas living together use similar calls in close proximity, so much so that orcas in captivity in close quarters with bottle-nosed dolphins have shown tendencies to adopt the dolphins’ unique forms of communication, which includes far more whistles and clicks. This is a phenomenon known as vocal plasticity, and demonstrates not only the orcas’ intelligence, but their desire to socialize with their neighbours.
Human Beings & Echolocation
To understand the unknown, it’s easier when we can relate to the topic. Enter Daniel Kish, a man born blind but leading a life that’s anything but. Daniel uses clicks of his tongue to navigate the world around him, and it’s gained so much attention that he was recently featured in the podcast Invisibilia as part of their pilot episode.
While it’s not a societal norm, Daniel has demonstrated incontrovertibly that echolocation isn’t isolated to whales and bats.
Although they’ve been perfecting it for centuries, echolocation is just one more secret of the deep we’re starting to fully appreciate.