OUR SENSES: TOUCH, FROM SINGLE CELL TO WHISKERS
Published November 15, 2017
[The Museum's logo animates out.]
[An animated planet rotates in space.]
[MUSIC PLAYS]
ROB DESALLE (Curator, Division of Invertebrate Zoology): Probably the first sense that any organism on this planet evolved was a sense of touch.
[POP]
[An oversized finger comes in from the side, and pushes the planet off-screen.]
DESALLE: Or a sense of pressure on a cell.
[SQUISHING, WATERY SOUNDS]
[A circle widens out to reveal animated single-celled organisms moving slowly.]
DESALLE: Now, of course, single cells don't have nervous systems. But they need to know when something's coming into contact with them.
[Two cells bump into one another. One retracts and moves swiftly in the other direction.]
[Curator Rob DeSalle speaks in his office. On-screen text gives his title as "Curator, Division of Invertebrate Zoology]
DESALLE: The sense of touch is a very important one for how we deal with the environment.
[An animated brain hangs from a pulley system. It moves downwards, tugging the rope along with it.]
DESALLE: One of the larger parts of our sensory cortex...
[Wider view of room where a Rube Goldberg machine is animated out—as the brain moves down, a rope and pulleys lift a wooden board, tipping off a weight, thus releasing the pendulum of a clock. Attached to the pendulum arm is a hand that moves back and forth with the movement, petting a purring cat that sits at the end of a mantelpiece.]
DESALLE: ...in your brain is connected to your fingers and to your hands.
[Close up of hand scratching cat's back.]
[PURRING]
DESALLE: The fine tuning of touch with our fingers perhaps made us kind of a unique species on this planet.
[Close up of cat's face, first eyes closed, then open with surprise.]
[MEOW]
[Animated receptors of various sizes, shapes and colors bounce slightly on springs.]
[BOING]
DESALLE: We have this menagerie of touch cells—
[Close up of a feather moving across a construction paper "cell."]
[TWINKLING SOUND]
DESALLE: ...different receptors that detect different kinds of pressure from the outside.
[Close up of a hammer banging onto a construction paper "cell."]
[BANG]
[The camera moves through a forest of animated cells, stretching and moving subtly.]
DESALLE: And one of my favorites is the Merkel cells that are disc-shaped neural cells in your skin...
[The scene whirls into an image of a fingerprint.]
DESALLE: ...that can detect very, very minute, miniscule changes in the surface of something.
[The fingerprint is pushed down, out of the frame. Two animated green hills appear. A large animated finger moves across them, and text appears indicating that the finger is able to differentiate a difference in 13 nanometers in height.]
[Finger pulls out of frame. Several animals animate in succession, stacked on top of one another—a donkey, a dog, a cat, a rooster, and a mouse.]
DESALLE: Other organisms have these touch cells and the classic example of this are whiskers.
[An animated, overhead view of a mouse's face, whiskers twitching.]
DESALLE: Each have a Merkel cell, and when they get slightly moved...
[The mouse moves forward and comes into contact with a piece of cheese.]
DESALLE: ...that's putting pressure on the Merkel cell...
[A brain appears overlaying the mouse's head. Dotted lines animate from the whiskers to the brain.]
DESALLE: ...and then that's sending a message to the brain saying....
[The shot widens out to reveal that the cheese sits on a mousetrap. The mouse sniffs at the cheese, whiskers twitching.]
DESALLE: ... "Oh, there's something really close to your face."
[MOUSE SQUEAKS]
[Mouse runs away from the baited trap.]
[MUSIC PLAYS]
[Card appears saying: "American Museum of Natural History, Our Senses: An Immersive Experience, Opens November 2017. Our Senses is generously supported by Dana and Virginia Randt."]
[Credits roll.]
Just like your pet cat, the Puma concolor—also known as the cougar or mountain lion—has a face full of whiskers. But these extra hairs, which typically grow along a cat’s snout, cheeks, chin, brow, and wrists, aren’t just for show.
Merkel Cells
Cat whiskers are packed with sensory nerve endings called Merkel cells, which serve an important purpose for these nocturnal hunters. All vertebrates—including humans—have Merkel cells in their skin, but the highest concentration can be found in mammalian whiskers (vibrissae), making the mountain lion’s fancy feelers some of the most sensitive hairs around.
Sight in the Dark
How does it work? Tight clusters of nerve endings at the base of each whisker, in the basal layer of the epidermis, can detect changes to air flow in the animal’s surroundings, indicating nearby objects and, perhaps most importantly, prey. A mountain lion's whiskers are so sensitive, they don’t need to make physical contact with an object to sense it. Vibrissae on the wrists sense movement close to the ground and can help a cat position its paw. And according Paul Leyhausen’s frequently cited 1979 study on the behaviors of both domestic and wild cats, facial vibrissae may help a mountain lion orient its bite as it captures and kills prey.
Glow Eyes
Don’t be fooled into thinking that just because mountain lions possess this incredible, extra sensory organ that they don’t have excellent eyesight. They do. This cat boasts a wider range of vision than most humans—they can see 285 degrees compared to our measly 210—and because their eyes have more rods than cones, their retinas are especially receptive to low light conditions. Behind their retinas, an additional cell layer called the tapetum lucidum reflects available light back through the eye, letting mountain lions see clearly at night. This feature is also the reason why cats’ eyes appear to glow in the dark.
Fun Facts
The Museum’s Mountain Lion diorama, which can be found in the Bernard Family Hall of North American Mammals, underwent a major restoration in 2012. In an effort to make the mountain lions look their best, Museum conservationists, working with Curator Ross MacPhee in the Department of Mammalogy, completed the painstaking task of replacing the cats’ whiskers. But mountain lion whiskers are harder to come by than you may think. The creative solution: African porcupine quills, which are similar in appearance and texture to real mountain lion whiskers, were used instead.
Learn more about the senses of different species in our new exhibition Our Senses: An Immersive Experience.