[quote]
about 4 foot doesn’t seem unrealistic quote]
I’m quite happy to accept that. In fact I never said any differently. The dispute was with the OP and numerous anecdotes of cats jumping 6 feet. Once we get to 5’ we are talking another 50% height, which is no longer equivalent. 6’ is over an 80% increase.
I’m quite happy to accept that. In fact I never said any differently. The dispute was with the OP and numerous anecdotes of cats jumping 6 feet. Once we get to 5’ we are talking another 50% height, which is no longer equivalent. 6’ is over an 80% increase.
**I’ve often heard it said that the plural of ‘anecdote’ is not ‘data’, however, the plural of ‘observation’ is. I’m going to see if I can capture some video footage.
**More than once in this thread, I have mentioned a cat jumping from a standing start to take a small bird from a suspended birdfeeder - no fence post involved.
I’m not saying a cat can’t gain purchase on a fence post, I am saying that it isn’t necessary for jumps of up to six feet in height.
To clarify, I did say differently. However I then pointed out that I said IIRC, and I recalled wrong. The height all animals can jump to is about 3.3 feet, not about 2 as I thought. My initial recollection was wrong, so the evidence seems to suggest 4’ is reasonable but not 6’.
Totally conceded, but you’ve got people’ backs up by suggesting they can’t trust the evidence of their own eyes when the data just isn’t there to give accurate figures
“about” means “about” - there’s wriggle room
In fact that is just what you did say:
You: “the roundness of the Earth and its motion around the sun is not a trivial thing to directly observe, whereas a cat jumping up from a crouching stance onto a fencepost is.”
Me: “I have provided one reference which suggests that it isn’t open to dircet observation because the hindlegs of the cat move so fast that it is difficult to see unless you know exactly what you are looking for.”
You: “The hind legs can move as fast as they like; the observations that people are talking about here include open jumps where there is nothing but air for the hind legs to gain purchase upon”
We were specifically discussing the difficulty of making observation of cats jumping onto fenceposts, and you stated that those observations include jumps with no purchase.
I suspect that you have simply become confused. If that’s so we can let this rest. If not then you will need to explain how observations of a cat “jumping up from a crouching stance onto a fencepost” can “include open jumps where there is nothing but air for the hind legs to gain purchase upon”.
An increase of 80% for a 6’ leap isn’t wiggle room is it.
An increase of 200% for the 3 metre leap which some are implying the serval makes is sure as hell not wiggle room.
People who see cats making 6’ leaps or 10’ leaps are not working in the realm of wiggle room. 1.8m is not about 1m. It’s damn near double.
I propose an experiment; I will procure an athletic domestic cat (or several) and I will attach a piece of attractive food (such as a whitebait or piece of chicken liver) to the end of a bamboo pole.
I will allow the cat to smell the food item, then I will hold the pole horizontally at the level of my head (I am 6ft tall) so that the food item is suspended over level ground with nothing but air below it.
If the cat succeeds in leaping up and touching the food, we can surmise that the cat is capable of a leap that takes its forepaws to a height of 6ft (which still places the entire cat’s body well over 4ft)
If the initial experiment is a success, I’ll try greater elevation.
What kind of documentation of my findings will you require, Blake.
The cat playing tricks with its CG doesn’t really explain getting on top of the fridge. If the center of mass doesn’t clear the top ledge of the appliance, there’s little hope that the cat’s entire body will end up there. Even if he could magically move all of his mass to his ass, grab the top of the fridge with his front paws, and pull himself up, it would still require moving his CG about 5 feet. And we know he’s not doing that.
Our somewhat overweight tabby has little problem getting on top of our nearly 6’ refrigerator. He’s declawed, so there’s no chance that he’s scrambling his way up. Besides, he makes it up in one smooth motion, obviously not touching anything…and it’s easily observable. It looks just like the animation posted above.
I’d try to capture some video, but he won’t do it anymore. Our fridge is currently by a counter that lets him get up in two steps. If I left a can of tuna up there to bait him, he’d take the easy way up. shrug
You’re being deliberately obtuse now; I have stated that I have seen a cat leap to a height of 6ft unaided by any purchase points on the way up(where there were none); I have also seen them leap to a similar height without appearing to use purchase points that were available, I’ve also seen them jump to a similar height using purchase points and I’ve also seen them jump, try to use purchase points, fail and fall off.
Is that clear enough?
I’m going to be honest. I don’t know what serval is. Looking it up, kind of a neat cat. I wonder they don’t have it a nature shows?
Anyway here is a site that confirms it is a jump 10 feet off the ground.
http://dspace.dial.pipex.com/agarman/serval.htm
Mangetout you are a long-time poster in good standing on these boards. If you will give me your word to undertake that experiment to the best scientific standards you can manage (for less than $5.95 at the K-mart checkout) I will accept the results. Just make sure they don’t take any run-ups.
I await the results with interest.
As I’ve said I’m as ignorant as the next man and I’m happy to be wrong on this one. I just need something more substantial than anecdote before I suggest that all those universities got it completely wrong. I trust you can understand that.
I’m very confused about what the running start issue has to do with anything. Blake’s reference refers to horses being able to raise their centre of gravity by about a metre. I don’t know that horses can do that from a standing start, though I guess I could be mistaken. I took the example to be referring to equestrian competitions in which the jumpers have a running start. Additionally, the height humans can jump is about the same from a standing start as it is from a running start, assuming we’re talking about elevation of the centre of gravity - good standing verticals are about a metre, and good high jumpers raise their centre of gravity by about a metre (whilst doing contortions so as to avoid hitting a bar).
In my experience, cats, when really jumping, don’t use a running start anyways. They coil themselves up and then explode upwards. So I don’t see why we should think that they’d gain any jumping ability from taking a few steps. Whether or not a running start will actually add any height to a leap very probably varies depending on the physiology of the crittur in question.
Nor did I see any caveats in Blake’s cites regarding running starts. The statements were all completely general, and were expressly on the topic of the relation between the height of jumps and the size of an animal:
Interestingly, this is the very bit Blake quoted. Yet it clearly doesn’t support his hypothesis, i.e., that no animals can elevate their centre of gravity by more than “about a metre”. What it says is that increasing the size of an animal that leaps many times its own height will not result in it being able to leap to proportionate heights, but rather that we should expect increases in size with other physiological variables held constant result in leaps of exactly the same height. This in no way implies that some physiological designs couldn’t be specialized in such a way as to leap considerably higher than “about a metre.” He has demonstrated that size isn’t relevant to the question of how high something can jump. He has not demonstrated anything else.
In fairness, I would submit that cats leaping onto fridgetops don’t count as a counterexample to Blake’s hypothesis, as we may suppose the cat’s centre of gravity begins at, say, 6" off the ground (actually I think they crouch lower than this when they do the high jump thing, but anyways), and fridge tops are usually 5-5 1/2’. So the cat is jumping 4 1/2-5’, or ~1.5 metres. I don’t think it’s unreasonable to include this under the umbrella of “about a metre.”
Likewise, whitetails clearing 6’ fences are in much the same ballpark in terms of elevation of centre of gravity. They start about 3’ off the ground, and need to get their cog to about 7’, so they’re actually not performing as well as the cats. 6’ fences are getting close to the limit for whitetails, as 8’ is the standard height for fences to keep them out (or in).
However, there are several outstanding and very reputable looking cites for cougars and such being able to leap to truly impressive heights.
That was never unclear. What was unlcear is how explain how observations of a cat “jumping up from a crouching stance onto a fencepost” can “include open jumps where there is nothing but air for the hind legs to gain purchase upon”. I assume form the above that you simply got confused about what we were discussing. If that is the case we can let it rest.
Apparently from “short bursts” of “high speeds”, which suggests that it is, as I suspected, a running jump and not done from a standing start.
never mind my cite. I read of as off for some reason.
I was only ever talking about standing starts form the very first post and have made that clear regularly ever since.
“they can, with little effort, jump as high as 4 or 5 feet, from standing still (no running jumps).””
“I doubt that.”
I saw no need more need to explicitely state a caveat about running starts than to explicitely state a caveat about operating in Earth’s gravity. But if you need one you can have one now. On both points. 
Go to a zoo, look at how differently a tiger is put together compared to yourself - are you twice as clever as a tiger?
Can your hands manipulate things with twice the precision as a tiger’s paws? - So why can’t you accept the possibility that a tiger can jump twice as far as you?
If we were talking an order of magnitude I’d agree with you, but hell, a I’d guess a fit human can jump twice as far as an unfit human - so a mere doubling is not that significant - it’s about design not how the laws of physics scale.
(- Anyway it’s too late here, and I’ve drunk too much to remain coherent - happy Yule to you all - I just hope someone will do a proper measured experiment that I can read about in the New Year! bye!)
Regarding the rest of your posts isn’t “this isn’t exactly what we find” there will be some variation but it won’t be great? If so then I said that in my second post.
I also doubt that anyone would think that an increase of 200% is just ‘not exactly’.
And then some I hope. But no one has ever suggested that all mammals are about as intelligent as one another. Or that calculations suggest we are but that in reality this is just not ‘exactly’ true. On the contrary people state that humans are in a completely different league to tigers intelligence-wise.
Because twice is more than ‘wiggle room’ and it is more than almost the same but ‘not exactly’ the same.
Merry Christmas.
That’s nice. I didn’t say anything about what you’d said about running starts. I said your cites say nothing about running starts. Care to point out where I’m wrong on this score? Care to point out why this whole running start thing is even relevant? The energy required to lift a given mass a given height is identical regardless of the horizontal velocity of that mass. The only way horizontal velocity can be converted to elevation is by means of such things as ramps, and then only if the friction involved in deflecting the kinetic energy off the ramp isn’t sufficient to dissipate said energy. And the friction involved in the absence of wheels generally will be.
So, basic physics tells us that running starts are irrelevant. And it does so far more clearly than it tells us that there is some fixed height beyond which nothing can leap. In fact, basic physics doesn’t tell us there is some height beyond which things cannot leap. Your cites do not claim that. They claim that size is irrelevant to the question of how high something can jump. Size. Not physiology.
Please explain why we should think your cites actually support your claim.