Is it true that elephants are the only quadrupeds that cannot jump?
Thanks to Colin Watters and others for pointing out this splendid YouTube video of an elephant on a trampoline at 鈥� Ed
鈥� This is a fun question, but it is not true even if we include only four-legged animals that routinely walk on land.
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Elephants cannot jump, from level ground anyway. This is true even when they are babies, as far as we know, but they are not alone. Probably all turtles cannot truly jump. It is also likely to be true for some salamanders and large crocodiles, some chameleons and other lizards.
In fact, the statement is almost certainly not true even if restricted to mammals. Hippos probably cannot or do not jump, along with moles and other burrowing mammals, sloths, and other climbing specialists.
However, the truth is that no researchers have looked at this question in a rigorous way. We don鈥檛 even know specifically why 鈥� in terms of detailed anatomical mechanisms and physics 鈥� any of these animals cannot jump. There are just scattered anecdotes and folklore, like the tired myth that elephants have four knees, which I still encounter again and again from the public. Elephants actually have two knees like all other mammals because their anatomy is essentially the same.
So the question is certainly worth addressing. But there are a lot of species out there, so as a general rule it鈥檚 probably best to assume there is unlikely to be any species that is alone in being unable to do some seemingly common activity.
John R. Hutchinson, Reader in evolutionary biomechanics, Royal Veterinary College, University of London, UK
鈥� Racehorses weighing about half a tonne are among the largest quadrupeds that can make impressive jumps. In horse racing, , the highest fence on the Grand National course, is 1.8 metres high.
The largest wild animal I have seen making an impressive jump was an eland, one of a group that I saw galloping in Kenya. Its jump was high enough to have cleared the back of another eland, roughly 1.4 metres from the ground. The animal probably weighed about the same as a racehorse.
Large male African elephants weigh around 5 tonnes, and Asian elephants only a little less. After them, the heaviest quadrupeds are the hippopotamus (about 3 tonnes) and the white and Indian rhinos (about 2 tonnes).
Whether these and other large animals can jump depends on what you count as jumping. A film I took of a white rhino galloping at 7.5 metres per second showed that, at one stage of its stride, all four feet were off the ground. I do not think of that as jumping, but I cannot think of any clear-cut definition of jumping that would exclude it.
Big jumps require strong leg bones and muscles. The vertical component of the force the feet exert on the ground, averaged over a complete stride or jump, must equal the animal鈥檚 weight. In a substantial jump, the animal is off the ground for longer than it would be in a running stride, so its legs will be subject to larger forces at take-off and landing.
Simple physics tells us that if big animals were precisely scaled-up versions of smaller ones, their weights would be proportional to the cubes of their linear dimensions. The cross-sectional areas of bones and muscles, however, would be proportional only to the squares. An animal with double the linear dimensions of another would be eight times as heavy, but its legs would be only four times as strong, and so less able to jump.
Of course, even closely related animals of different sizes are not scale models of each other. For example, a 500-kilogram eland has relatively thicker, straighter legs than a 5-kilogram dik-dik 鈥� but the differences are not sufficient to eliminate the disadvantage for large jumpers.
Other than size, a quadruped鈥檚 anatomy or physiology may be unsuitable for jumping. Some desert lizards that burrow in loose sand have greatly reduced limbs, tortoises have very slow muscles and the limbs of moles are highly modified for digging. I have never seen any of those quadrupeds jump, and do not expect to.
鈥淎n animal鈥檚 anatomy may be unsuitable for jumping. I have never seen a mole jump, and do not expect to鈥�
R. McNeill Alexander, Emeritus professor of zoology, University of Leeds, West Yorkshire, UK
鈥� Elephants are not the only quadrupeds that cannot jump. Some of the quadruped dinosaurs could not jump, including apatosaurus and diplodocus.
Edward Rivers (aged 7录), Angmering, West Sussex, UK
鈥� Really heavy animals like rhinos and hippos can hardly jump or land without injury. After reaching terminal velocity, mice would bounce after hitting the ground whereas elephants would break.
Even so, don鈥檛 jump to optimistic conclusions if a large animal chases you over a ditch. Does it still count as 鈥渂eing able to jump鈥� if the jump causes the animal injury? If so, then you are in trouble because, yes, Indian elephants can jump. J. H. Williams in his book Elephant Bill relates how a stampeding female jumped a ditch handily, though she went lame in both forefeet soon after.
Jon Richfield, Somerset West, South Africa