Re: Can camels swim?

Cecil's Columns/Staff Reports
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If we include the entire animal kingdom, there’s LOTS of things that don’t swim. Even some aquatic animals, like sponges, or the bottom-dwelling clams, for instance.
As for vertebrates, they all evolved from fish and would have to have lost the ability at some point to qualify. On a planet as watery as this, that seems like it would be real survival disadvantage; even deserts flood occassionally.
What candidates do we have? If memory serves the only uncontested vertebrate entry is the giraffe. Frankly, I’m skeptical. They may not be great swimmers, but they have big lungs and, one would expect a large center of buoyancy well below their nostrils. They might not propel themselves in the water terribly well, but I would think they’d float with their heads above water and be able to move along as well as, say, a horse. Until I drown one myself, I’m inclined to withhold judgement on the giraffe as a non-swimmer.

I think what we’re looking for is a creature with a body plan in which it either (1) cannot float (2) cannot, while floating, keep its mouth or nostrils above water, or (3) has no limbs that can move it through the water. These are the things that seem to constitute “swimming” to me.
For (1), vertebrates have either lungs or gills, and I’m unaware of any vertebrates with gills who can’t swim. So if an animal has lungs, it should generally float unless it’s tissues are extremely dense (although I, personally, will sink to the bottom of a ten foot pool unless I keep my lungs fully inflated). I can think of two ways tissue density could become very dense - shells, like with turtles, and absorbent materials like fur or feathers that could become water-logged. Turtles can swim, and I’m unaware of any animal that can become so water-logged it can’t float (that may just be my personal ignorance, though, they don’t really focus on this stuff in biology class. If there is a non-swimming vertebrate, this may very well be the reason).
Wrt (2), an animal may float but be unable to float in an orientation that lets it breathe. I don’t know of any such case, but it’s possible. Any land dweller where the center of gravity was closer to the mouth than the center of buoyancy would be a candidate.
As for (3), it’s highly unlikely. Literally any limb that moves ought to be able to provide at least SOME propulsion, and even the limbless snakes can swim quite well.

So there’s a few characteristics to think about, but I know of no vertebrate that exhibits them so strongly they can’t swim.

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Thanks for the interesting post, APB.

[[So there’s a few characteristics to think about, but I know of no vertebrate that exhibits them so strongly they can’t swim.]]

Except this guy I know named Leon.

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WARNING ! A graphic description of animal experimentation follows:

I submit gophers as a candidate for non-swimming vertebrate. Some time ago, my brother was battling gophers at my parent’s farm and utilized several methods of doing away with them. As an experiment, he managed to capture one alive and tossed it into a bucket of water. It sank like a rock, emitted a few bubbles, and…well, he concluded that gophers could not swim.

A gopher has tiny limbs in proportion to its body. I would guess this is so it can squeeze through its burrow, but it makes them useless for swimming purposes. The way the gopher sank suggests it cannot rely on buoyancy to help it swim.

Perhaps other burrowing creatures, such as moles, are incapable of swimming ?

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…They cannot swim, or even stay afloat. Because of an incredibly large head, dense & heavily muscled little barrel body & short legs, they’ll sink like a stone if put in water deep enough.

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Aren’t they a product of human selection, rather then evolution?

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Regarding moles, the Star-nosed Mole (so named from the pink tentacles that surround its snout) is highly aquatic and an expert swimmer and diver. But even the common garden mole can swim fairly well (ref: Walker’s Mammals of the World).

Given this, the observation of the drowning gopher is somewhat surprising, since one would not necessarily expect them to have less swimming capacity than moles, based on anatomy. The references I have consulted so far are mysteriously silent on the subject. Perhaps the animal in question saw the end was near in any case and decided to drown itself in despair. Clearly more experimentation is needed. For what it’s worth, gophers tend to be found in drier areas than moles, and so perhaps encounter water less often. (Maybe I need to try looking this up under “Varmint Control” rather than “Mammalogy.”)

Excellent post by APB, which nicely summarizes the anatomical constraints. However, one factor missing is the psychological side of the question. An animal could be perfectly capable of swimming with respect to its anatomy, but drown if it reacted adversely to finding itself in the water. This was part of my speculation that many smaller land birds might not be able to swim (even though they float very well, and are capable of moving their limbs in the water). Interesting post on the swimming eagle, BTW.

Psychological factors may in fact have something to do with the apparent inability of the Great Apes to swim, even though they are anatomically so similar to humans. In “The Apes,” (Vernon Reynolds, 1967, pp. 87-88) we find the following rather definite statements:

“Swimming ability is almost nil in the apes. A young gibbon that fell into a pond at a zoo drowned while its mother watched, too afraid to rescue it. No report of swimming by a gibbon exists, but several others confirm its inability to swim. Orangutans have never been observed swimming, and probably cannot. Gorillas, faced with the alternative of capture by man, dare not go into water more than two or three feet deep. They have never been observed to swim, and at least one mature male has drowned in a zoo water enclosure, sinking as soon as he fell in. Only in chimpanzees is there some evidence for swimming ability. [Reynolds then cites a report of four chimpanzees seen swimming across a river in Africa, but then says he is inclined to think it must really have been some other species.] In captivity, attempts to teach chimpanzees to swim have met with failure, and deepwater barriers have often proved efficient in keeping apes on islands, as for example at the Paris Zoo. The general response of chimpanzees to water is universally agreed to be one of avoidance and even fear. I have myself on two occcasions helped pull chimpanzees out of a water-filled moat in which they were quite clearly drowning, and I am convinced they cannot swim, although in their stuggles as they flounder about they can sometimes make a little headway in the water.”

I think the jury is still out on giraffes, though APB’s points incline me to reverse my earlier opinion that they could’t. Awkward they certainly might be, but I don’t see a definite anatomical reason why they wouldn’t be able to swim, particularly with the neck stretched out horizontally to the water.

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PS. As a follow-up to my previous post, the case of the “drowning gorilla” mentioned in many references seems to be based on an incident at the Bronx Zoo in the late '40s or early 50’s, when a full-grown adult male gorilla tumbled into the moat of his enclosure and drowned with scarcely a struggle in full view of a crowd of horrified and astonished spectators. When I find out the name of the gorilla, I’ll let you know.

Earlier in this thread someone speculated that kangaroos might not be able to swim. No luck. They do. Peculiarly enough, they use the hind feet alternately while swimming, something they appear to be quite unable to do on land (always hopping, never walking).

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Still waiting for the name of the gorilla… Jeez, get with the program here, Colibri.

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Patience, Jill, patience. These things take a little time.

The name of the gorilla was Makoko, and the incident happened in 1951. The moat was six feet deep. (ref: Maple and Hoff, 1982, Gorilla Behavior, p. 236.)

The obituary mentioned that “the family requests bananas be sent in lieu of flowers.”:frowning:

Sorry this took so long.

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Of course, there is a danger in generalizing about a species from one sample of the species.

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True, CK, but the unfortunate Makoko is only one example of many (if perhaps the most famous one). I have also seen cited a case where no fewer than four chimpanzees drowned at a single facility in moats or small pools over a relatively brief period of time. ALL the technical and popular literature I have checked (and at this stage it’s a lot) is absolutely universal in the opinion that swimming ability in all the apes is at best minimal. Most state unequivocally that apes (gorilla, chimpanzee, orangutan, and gibbons; many monkeys, including some that are informally called “apes” can swim well) do not swim. The more cautious authors will say “appear to be unable to swim,” while some will venture the opinion that “perhaps young ones could be trained to swim,” although the experiment seems to have been made often and I have never seen a citation of a success.

The only specific citations for swimming apes I have seen so far have been (1) the four chimps dog-paddling across a stream in Equatorial Guinea I mentioned in a previous post, but considered as doubtful by Reynolds; and (2) a pet orangutan that was lured aboard a steamer in an attempt to “kidnap” it from its owner. When the steamer pulled away from the dock, the ape jumped overboad and managed to make it to shore. Ever afterward he would flee to the jungle whenever a steamer was in town. But he seems to have been the veritable Johnny Weismuller of anthropoids. (Please do not ask me the name of the orangutan. I can probably find out, but I don’t have the time right now.) And as you say a single example does not make a case.

This is quite mysterious, as I said, because apes are anatomically so similar to humans. Occasionally someone will speculate about a physical cause, such as the “center of gravity (OK, mass)” argument, or that apes may have low body fat. But while the “center of gravity” argument could conceivably apply to an adult male gorilla, in which the heavily-muscled shoulders could force the muzzle under, I don’t see how it could apply to a young chimp. The body-fat argument is slightly more plausible, as it is often mentioned that a drowning ape “sank like a stone.” However, many captives, at least gorillas, are obese and should be able to float. I have seen no general data on body-fat percentages to back this contention, and I think people are just grasping at straws.

What seems to be the case is that apes are simply psychologically averse to water, at least deep water, and when they fall in or are placed in it they just go bonkers and thrash around helplessly until they drown (or sometimes don’t even struggle). This happens even if they are only a few feet from shore. There are few healthy adult humans, even non-swimmers, that would not be able to rescue themselves in such circumstances, but apes very often don’t. There are any number of anecdotes in the literature of owners placing a gibbon, orang, or whatever (usually young, but sometimes adult) in the water as an experiment and then having to rescue it when it became distressed and started to go under.

Some young gorillas will play in a basin of water, but others seem to be afraid of it. On the other hand, virtually all human babies will play happily in a pool. And apes in nature seem to be averse to crossing even shallow water; in “The Mountain Gorilla” George Schaller mentions that they will usually cross even small streams on fallen logs to avoid wading.

Distribution also argues that apes rarely if ever cross water. The range of the Eastern Lowland Gorilla is circumscribed by the Niger and the Congo (Zaire), while the Western Lowland Gorilla is found a great distance away at the headwaters of some of the Congo tributaries. The ranges of the eastern and western subspecies of Common Chimpanzee is likewise split by the Niger, and Common Chimps are not found south of the Congo. The Pygmy Chimp (Bonobo), usually considered a difererent species, on the other hand, is restricted to the south side of the Congo. While Orangs occur on the larger islands of Indonesia, they seem to have been isolated there by rising sea levels after the Pleistocene. And the ranges of some gibbons seem to be limited by major rivers in Southeast Asia.

So there you have it. There seems to be a mountain of evidence, both anecdotal and experimental, that if apes swim at all, it is only under the most extraordinary circumstances. They have rarely if ever been observed to swim in nature; in captivity they often drown in pools of water only a few feet wide; and when experimentally placed in water they show great distress and usually have to be rescued. While I would not totally rule the possibility that one could be taught to swim with persistent effort, I have so far seen no reports that this has ever been done.

Why this might be so is extremely puzzling. Since monkeys swim, apes must have lost this ability at some point; and humans somehow regained it. But we definitely seem to be an oddball in our little branch of the family tree.

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PS. In my last post I inadvertently switched the ranges of Eastern and Western Lowland Gorillas. Sorry.

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[[In my last post I inadvertently switched the ranges of Eastern and Western Lowland Gorillas.]]

Well, duh.

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I always thought bulldogs could not swim, or at least I’ve seen people almost drown them in the attempt. They can’t keep their short noses above water.

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I don’t think that we can count bulldogs, because we’re really discussing species which are incapable of swimming, and there are countless other specimens of Canis familiaris (or Canis lupus familiaris, if you prefer) that do swim, and, in fact, love the water.

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It seems that many people don’t take Desmond Morris seriously nowadays, but didn’t he suggest in his book “The Naked Ape” that humans were at one point of their development aquatic animals? Which (along with neoteny - the keeping of some of the embryo’s characteristics) would explain why we have no fur coat?

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I’ve heard about the aquatic ape theory. That’s why we’re hairless, and some other points I don’t recall offhand. I think our walking upright was part of it.

Links found under “Aquatic Ape”:
http://204.94.86.93/1.html
http://www.primate.wisc.edu/pin/aquatic.html
http://homepages.tesco.net/~sondela/
and
http://imprint.uwaterloo.ca/issues/100496/4Science/science03.html

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Seems that I recall that Morris mentioned this theory in the book (I don’t think he was the first to propose it, but I could be wrong), but as I read it a long time ago and am too lazy to go look it up (today, anyway), I can’t tell you the specifics. However, I don’t give it much credence. IIRC, the hypothesis relied on arguments about the possible (former) adaptive values of some rather unconnected features (e.g. hair distribution, supposed “webbing” between fingers, etc.); but I think it is amply contradicted by the fossil record, human developmental patterns, etc. I think it was proposed when very little was known about human evolutionary history.

What we really haven’t discussed yet is the basis for the apparent difference between apes and humans in swimming ability. Is human swimming ability entirely learned, or is there evidence for some innate ability?

At least for adults and older children, humans show little more instinctive swimming ability than apes; an adult or toddler that has never learned to swim will usually quickly drown in deep water (although as I remarked earlier possibly able to save him/herself in circumstances where an ape would drown, such as in a narrow moat; but this could be due more to intelligence than instinct).

On the other hand, I have heard that very young human infants, pre-walking, will swim, apparently instinctively, when placed in water. Can anybody confirm/contradict this? If so, it would be very interesting. If it exists, at what age is this ability lost?

While I stated earlier that even young apes appear to be unable to swim, I doubt that the experiment has ever been made on a very young ape. It would simply be too risky to place a valuable infant gorilla or chimp in the water.

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I tend to think that giraffes could not swim. One of the reasons why most paleontologists gave up on the idea that the sauropods spent most of their time in the water, with only their heads above the surface, was that the water pressure at those depths would be so great that they would be unable to draw in more air. I’d think that the same thing would be true of the giraffe, in water deep enough that they would not be able to reach the bottom their body would be completely under the water, the pressure on their lungs being much higher than the air pressure on the surface.

Why would a giraffe need to swim, anyway? There’s not much water in their habitat they could not wade across.

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I was going to point out that humans have to be trained to swim (except for young infants, as pointed out above). Swimming was an uncommon skill until fairly recently in our culture, and in others it is still something most people never learn to do.

But on the other hand, there are certain members of my family who taught their kids to swim by dumping them in deep water and letting them figure it out themselves. This is usually done at a fairly young age (5-7) but still far past infancy. I didn’t really learn to swim until I was 11, but one time when I was younger I got dumped in deep water (my cousin didn’t realize I couldn’t swim yet) and my sister says after thrashing around for a moment I managed to swim to her, about 8 feet away.