Five things you never knew about whiskers [bbc.co.uk]

DR ROBYN GRANT: I study whiskers because they're just the best.

DR ROBYN GRANT, SENSORY BIOLOGIST, MANCHESTER METROPOLITAN UNIVERSITY (WHISKER EXPERT). Most mammals, they have whiskers, and what's exciting about them is that there's so much stuff that we don't know. I like to look at something that we see every day and then find out really cool and interesting things about them.

WHY WHISKERS ARE EXTRAORDINARY. Lots of people, when they hear about whiskers, they think immediately of cat whiskers. But, actually, other animals have much better whiskers - they're more sensitive, they're bigger, they move more than cats' whiskers. Porcupine whiskers are just the longest whiskers I've seen. The one that I've got back in the lab is about 45cm long, and they move them almost continually, and then they kind of bump and move and vibrate around over the material that they're on so you can really see that they're moving all the time. Hi, gorgeous!

GFX: OUR ANCESTORS PROBABLY HAD WHISKERS. It's very difficult to study the evolution of whiskers because hair isn't really preserved in the fossil record. So we have a look at this little hole here which is called the infraorbital foramen, - or whisker holes. And all the information from the whiskers, from those sensitive follicles, travel through that hole and into the brain. Humans are really quite unusual to not have whiskers. But we do still have these whisker holes where our whiskers would have been and, also, we even have some remnants of muscles, similar to what we see in animals with whiskers.

WHISKERS ARE LIKE OUR FINGERTIPS. Whiskers are very much like human fingertips. Lots of animals can move their whiskers and then some animals engage in what is called whisking. So this is cyclic forward and backward movements that the animals make with their whiskers. And we might think of this as scanning. So, when we walk into a room, we might be looking around everywhere, trying to see all around us, and that's what these guys are doing. And the fastest whisking that I've seen has been in harvest mice, which reach up to about 25 times per second, which are some of the fastest movements that mammals can make. The most sensitive whiskers are in aquatic mammals. Lots of seals will have kind of just under 2,000 nerve fibres surrounding all of those whiskers in the follicle and their whiskers are so sensitive they can do this amazing thing which is called hydrodynamic sensing. So, as a fish swims through the water, it leaves behind a wake, a trail of water movement, and the seals are able to detect this. And they use only their whiskers for this.

THERE'S NOTHING RANDOM ABOUT WHISKERS. These are porcupine whiskers and you can see that they're arranged into a grid, or whisker map. So you have rows and columns of whiskers. So they're very ordered. The same grid-like pattern can be seen in physical structures through the brain, and now neuroscientists love this because it means they can actually tweak one whisker here, so a middle whisker, and they can follow it through the entire brain to see where that sensory signal goes, and each physical structure will light up in turn.

NEVER TRIM A WHISKER. In many animals, whiskers are their primary and most important sense. So it's very, very important not to trim them. It wouldn't hurt them, but they'll suddenly remove a sense. So it would be like if you blindfolded us and then put us in a room, and so we've got to feel around to work out where we are, and that is what these animals are doing all the time. We can see that, when we look at rats and mice, that some of them will actually engage in a behaviour called barbering. So this is when you have a dominant individual that will trim the whiskers, so bite off the whiskers of their family or other people that live in their box. And so, when they do that, those individuals will become more submissive. So it establishes this hierarchy within the cage.

WHISKERS HAVE A LOT TO TEACH US. Whiskers can inspire lots of new technology and innovations. Firstly, we can have a look at their shape. So the undulations of seal whiskers has inspired, for instance, turbine blades. So turbine blades can be extra-aerodynamic because they have these amazing undulations or waves along them. These could also be applied to tidal energy, as well. Then you have the fact that they are sensors. You can put these sensors onto robots. So, then, you can have tactile robots or whisker bots. And these could be really useful for something even like a robot hoover. But also to make sure that robots can go into hazardous, dark or complex environments. These are the environments we need our robots to go into. So people don't really think about whiskers at all. You probably go home and look at your cat or your gerbil or your rabbit and you think, "Oh, yeah, they're fluffy and have whiskers." But, actually, what we're doing is trying to understand, "Well, how do they work, and how sensitive are they, and what do they use them for?" And I think that that's super interesting to find out.