For the weekend, we have a 3.5-minute National Geographic video explaining why cheetahs are so fast (they’ve been clocked at 75 mph or 120 kph: an enormous speed). New slow-motion video has helped us with the answer.
The key is their spine. Look how immobile their heads are while they’re running: they have to keep their eyes on the prize!
The late Milton Hildebrand, who taught Vertebrate Morphology at UC Davis back in the 1950s-1980s, calculated that a cheetah with no legs could still run 3 mph thanks to that flexible back.
That video is gorgeous. To see the spine flex like that and the steadfast concentration on the prey is just elegant.
I never realized they aren’t fighting animals.
Thanks. Interesting.
That is cool! The shorter head would reduce its weight and create ease of control. A lighter camera is much easier to hold in place than a heavier camera. But a shorter head also means that incidental movements translate to only small degrees of arc of movement. The Cheetahs own visual image will look much steadier.
Try it by hand holding a camera and looking through it. With a short lens, I can keep the field of view pretty steady. But with a longer lens, what I think are the same incidental movements translate to big arcs of movement in the viewfinder.
+1
Nice Analogy.
I have to question that analogy a bit, sorry!
I am pretty sure – I am no physicist – that a heavier camera is easier to hold in place than a lighter camera. It is the photographer that is moving, and a heavier camera, with its greater mass, should have more inertia than a lighter camera, and should therefore resist that movement better.
On the other hand (I think it gets really complicated fast!), of two lenses with equal magnification and mass – one short, one long – the physically shorter lens would seem easier to hold steady as Mark said, but I am not sure about even that.
On the third hand, most “longer lenses” have more magnification than “shorter” lenses, which means their field-of-view is much more narrow than a “shorter” lens. Any camera shake therefore translates into a much greater relative change in the viewfinder. Which is why most telephoto lenses use image stabilization and are generally also used with a monopod or tripod.
On the fourth hand, most telephoto lenses weigh considerably more than shorter lenses, and would therefore resist camera shake relatively better than a lighter lens.
On the fifth hand (I ran out of hands three hands ago), the cheetah is constantly shaking and controlling its head with muscle movements. While a heavier head with its higher inertia will resist shaking better than a lighter head, it also would require more energy to perform any corrections, and muscles – unlike cameras – tire out.
It is interesting that in-body camera stabilization does not stabilize the entire camera – it only stabilizes a very low mass component – the sensor. So, the cheetah’s relatively low-mass head should be easier for muscles to stabilize than a heavier head, although that would mean it would be giving up something in the inertia department.
Evolution in action…. Except that if the cheetah/camera analogy was perfect, the cheetah would be stabilizing its lowest mass component – its eyes. But instead, it stabilizes it head and I think birds of prey do that also, Probably says something about the range of correction of eye muscles and their energy reserves.
The cheetah is stabilizing gaze. Gaze depends on head position + eye position. The reflexes to keep those two steady are the vestibulocollic and vestibuloocular reflexes, respectively. Both depend on vestibular input which depends on mechanically exquisitely sensitive hair cells.
All vertebrates do this. See my comment below.
Peggy
Very nice. I never tire of watching the amazing things cats can do and modern technology makes the watching even better.
Stunning clip. Holding that head steady is key.
I’ve seen them many times in the wild. Gorgeous animals, but sadly, they are in decline. According to the IUCN assessment: “About 6,500 mature individuals remain in the wild, according to the most recent IUCN assessment in 2021, and they continue to decline..”
Also, a slight disagreement with the zoo-keeper/trainer. There are occasions when males do hunt together.
“Most cheetahs hunt alone, but male siblings sometimes stick together to form a group, called a coalition, to take down larger prey, including wildebeest and kudu.”
https://www.ifaw.org/au/animals/cheetahs
Fascinating. Two quibbles.
First, vertebrates have a lot of neuro-real estate devoted to keeping the head steady. See this fabulous video:
https://www.youtube.com/watch?v=nLwML2PagbY
This ability is based on the hair cell (another vertebrate thing – we will detect gravity!!) and its sensitivity to head acceleration illustrated here:
https://www.youtube.com/watch?v=pij8a8aNpWQ
I have now “shot my wad” with my two favorite neuro-videos.
So to recap, the quibble is that the cheetah’s large nasal passages may be unusual and well adapted to its oxygen-consuming fast twitch-dominated muscles but its holding its head steady is basic vertebrate fare.
The second quibble is simply that, similar to the alligator, the cheetah has to do some jaw stuff which is non-trivial. So, yes, the cheetah runs and that is important but once it gets where it’s going, the cheetah has to open wide and clamp down fast, breeching no argument from the chomped upon prey.
Great post.