(I am not a doctor, nor do I play one on TV. My assumptions below are based on reading Wikipedia, so they are very likely to be incorrect. ;) Any corrections are welcome.)

So there's this woman who has been injured and is bleeding out. Our Hero is with her, but there is no one else around to help. After putting pressure on the wound, he wants to give blood to her to stabilize her or at least buy her enough time to get real help.

The catch is that he's currently in the form of a jaguar, and cannot change back to a human in time. He has all his normal human intelligence, but he has paws instead of hands and he doesn't exactly have any IV tubing with him, anyway.

So, two questions:

  1. How could one do a field blood transfusion while in the form of a jaguar?
  2. I know that a single donor couldn't "cure" serious blood loss. But could it be enough to get her to a less serious stage of blood loss, so that she has a chance of survival in a hospital setting?

(Please ignore the very real risk of transfusions with animal blood.)

The overall plot point is to get jaguar blood into the woman's system, something that I can't imagine occurring outside of some very dire circumstance like the above. But if you can imagine another scenario, that's welcome too!

EDIT: Does it change anyone's opinion if the woman is herself a doctor (low-tech, "typical" fantasy environment), with supplies, say? Could she recognize that her bleeding was going to get serious soon, so before that, she started the transfusion herself? The first transfusions were in the 1600's; what equipment did they use then?


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    $\begingroup$ Find someone and say"if you don't do perform this transfusion for me, I'll rip your throat out, human!" $\endgroup$ – RBarryYoung Mar 26 '15 at 4:30
  • $\begingroup$ Could the hero have enough time to shapeshift just his paws back into human hands? I imagine this would look pretty disturbing, and it would still have it's share of complications, but at least he'd get opposable thumbs back. $\endgroup$ – Seth Mar 26 '15 at 22:36
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    $\begingroup$ I wouldn't worry about transfusion risks. You're trying to keep them alive to get to the hospital. $\endgroup$ – Loren Pechtel Mar 27 '15 at 3:07
  • $\begingroup$ @LorenPechtel Exactly! I intend for her to have a bad/serious reaction, but under proper care she makes it. $\endgroup$ – Arthaey Angosii Mar 27 '15 at 6:59
  • $\begingroup$ I did a double take when I saw the title of your question :) You know, it is shapeshifter blood. Perhaps if he gets any at all in her bloodstream it will morph into her blood type. Or better yet, make her a partial shapeshifter. (Just watching out for e lives of innocents here.) $\endgroup$ – Xandar The Zenon Feb 12 '16 at 4:20

For all the reasons that MontyWild presented, I don't think the jaquar can actually perform the transfusion. RBarryYoung's idea in the comments on the OP is practical, but all of MontyWild's challenges apply, even with human hands and human dexterity. I wouldn't want to attempt a transfusion with a ball point pen. Would you?

Reducing your scenario to its barest facts, you are trying to get the jaquar's blood into the woman, presumably with the intention of infecting her with feline-lycanthopy. Why doesn't he just tear his paw with his teeth and then press his new wound to either her mouth or her wounds? I know that that makes his act of infecting her deliberate and I sense that you would prefer that it be an accident; still it gets your characters from where they are to where you want them to be.

Alternatively, the cat could just lick the woman's wounds in an attempt to clean them, or just to comfort it's dying mate. This would be in-character for a big cat so it might be more instinctual than rational; again it would get some of jaquar dna into the woman's blood stream.

  • $\begingroup$ Especially if the jaguar was already injured by whatever injured the woman, he tries to clean the wounds and blood from his injury enters her. $\endgroup$ – Tim B Mar 26 '15 at 9:50
  • $\begingroup$ If the intent is to transfer his lycanthrope blood does he necessarily need to be in jaguar form? $\endgroup$ – James Mar 26 '15 at 19:29
  • $\begingroup$ The problem is that this magic isn't actually shapeshifting, but rather possession. I thought thar aspect wouldn't be important to the question, but clearly I misjudged. My apologies! So he is only controlling the jaguar; his human body is elsewhere, not nearby. $\endgroup$ – Arthaey Angosii Mar 27 '15 at 6:56
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    $\begingroup$ Possession, not shapeshifting... Oh. In that case, it's easy! ...just kidding. It is still impossible. But it does leave you with a rather interesting opportunity. Have your jaquar-possessing wizard relinquish his hold on the jaquar to the wounded woman. Have him pull her soul out of her dying body and afix it to the perfectly healthy jaquar body. She gets to survive as a human intellect jaguar and together they go off in search of an unoccupied human female body for her to move into. $\endgroup$ – Henry Taylor Mar 27 '15 at 12:36

That's actually pretty hard to do without some sort of tubing small enough to insert into a vein, let alone by someone who currently has lousy digital dexterity. Even if the were-jaguar had an IV tube, with those paws, he wouldn't be doing any transfusions, and without IV equipment, or only improvised equipment, there's almost no way.

If you had, say, the empty part of the ink tube from a pen, you might be able to do it, but with a tube that size, using only normal blood pressure, it might take a while to transfer enough blood from the donor's arteries to the recipient's veins, but that presupposes that the were-jaguar has enough dexterity to pull the job off, which I doubt.

Puncturing an artery and using blood pressure to force the donor's arterial blood into the recipient's veins using simple physical contact might sound like a practical solution, but it is likely that most of the donor's blood will end up on the ground, as blood is slippery, lining up two cuts is difficult, and the pressure required to hold the edges of the cuts together would collapse the already exsanguinated recipient's veins.

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    $\begingroup$ +1 for the image of a jaguar holding a ball point pen, trying to get the ink tube out and empty it. $\endgroup$ – Henry Taylor Mar 26 '15 at 5:12
  • $\begingroup$ Hmm. Let's say the Jaguar managed to get the tubing of the pen aligned between two small cuts, one on each body. Then, he could use physical exertion to increase his blood pressure relative to hers. $\endgroup$ – jpaugh Mar 26 '15 at 20:32
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    $\begingroup$ Sending blood through an empty tube can be a very bad idea. If you ever see someone giving an improvised transfusion on TV this way, that's actually a really good way to kill the recipient! Unless you make sure that the tube is filled with blood before sticking the needle in, it's going to contain some air, and pushing air into someone's veins--even a very small amount--will cause a fatal embolism. That's why doctors hold a syringe upside down and push the plunger until some of the serum spurts out: to make sure there is no air inside! $\endgroup$ – Mason Wheeler Mar 26 '15 at 20:48

I have to agree with the others on this one.

I wen't through EMT training when I was in high school and we had to practice inserting IV's on each other...I still have scars.

Even with a bit of training and human manual dexterity, inserting an IV with the proper equipment is not a simple thing. If you compound that problem with no equipment and feline manual dexterity...the short version...completely impossible.

A little more depth

  • To do a transfusion correctly you need a pump, to assist in transferring the blood...now, you could claim that your were-jaguar's extra power etc, means his heart beating provides enough pressure...that I could buy.

  • You also need something sharp enough to puncture the artery, meaning small and pointy. If this isn't the case you are more likely to smash the vessel and cause internal bleeding and bruising. (maybe he has hollow fangs he can pull out of his own mouth and use...)

  • Dexterity. This process requires impeccable precision. Angle of entry, and the depth of the insertion are very important. Paws just aren't made for that...especially if he has to insert one into himself...without thumbs there is no way to effectively grab and hold something that can do this. I would have to suggest he transform back, execute the hard part, and then if needed turn back into his were self. That or introduce a third character that can do it for you.

  • $\begingroup$ I don't believe a pump is actually needed. 1) The blood pressure of the donor is almost certainly higher than the blood pressure of the recipient. A simple connection should work. 2) Assuming a sufficiently flexible tube you could pinch it and run your fingers down the tube--a crude pump but you don't need a lot of pressure. $\endgroup$ – Loren Pechtel Mar 27 '15 at 3:04

I'm with most others on this one, and would not write up a Transfusion attempt.

If your goal is indeed ultimately to have some of the jaguar blood end up in the woman, I would suggest a scenario where both are wounded.

The woman can still be in a critical state, but the jaguar is also wounded. He tried as best he can (dexterity eh) to pull her onto himself to transport her as fast as possible where she can get help. In doing so she may come in prolonged contact with an open wound he's suffered. Makes his efforts to save her all the more dramatic and the mixing of the blood and whatever it causes all the more concerning. (Its an accident/ it wasnt noticed/ he should have noticed/ hes at fault/ etc...)

  • $\begingroup$ I like this alternate solution best, because it still gets the jaguar blood into her. This will probably be a much smaller amount of blood transfer, right? I guess I'll just have to declare that it's enough anyway for my later plot purposes. ;) $\endgroup$ – Arthaey Angosii Mar 27 '15 at 6:58

The time to shape-shift probably is related to the amount of stuff to be done, both overall quantity and the extent of the difference for a given element. Bones are the most difficult and some of them change their size substantially: the vertebrate skeleton is the same for all, just stretching and shrinking individual bones, especially so if sticking to mammals.

To work in a pinch (pun intended) he just needs thumbs. In fact, it might be handy enough (pun intended) to keep a modification to pure feline form normally, to do little things like open doors and take notes without having to change back.

paw illustration

You might find how to draw very interesting too from Wikipedia how to draw

Without trying to work out and build a complete working model, you could say that the dewclaw digit is elongated and the (retractable!) Claw shaped like a tweezers tip rather than a hook; and the pisiform (E in illustration) is also extended and the end shaped as a teardrop, offering a broad anvil plus a fine tip, either of which can be used in opposition with the tweezer limb based on the claw extension mechanism for the large open/close movement, plus a little bit of movement in the finger proper to adjust the position. The tear-drop shape is wavy, offering a notch as well, with idea of being able to grasp a pen or some-such using that feature.

Without compromising his ability to use the fore paws like a Jaguar would, he can hold a pen and pick up small objects like coins. For anything more, the paw could transform much quicker than the whole body! It would offer continuous improvement to dexterity over the few minutes it takes, and his practiced trick is aimed at making the best effects from the smallest (fastest, energetically cheapest) modifications, changing the bones only slightly, curving rather than changing the length of the bones (that is the hard part), and gain dexterity at the sacrifice of leaping/clawing/running ability.

So, when faced with the need for hands, he naturally starts a well-rehearsed shift to improve his hands. Maybe opening the medikit case is a problem, being too large of a grip to work the latches; so he uses alternative means to open it; then going through the contents is no sweat, but opening the envelope packaging is like trying to open a ketchup packet with heavy gloves on and using a chopstick, so stomp on it to hold it down and claw it open instead. Grasping the tubing and needle is no problem at all, and by then his hands are becoming more useful.

Though useful in a limited sense, the sum total of manipulation abilities, strength, scale, grip etc. is all wrong so the task is awkward in interesting ways.

But, he can effect custom changes for the task at hand; changing the way a joint faces or the shape of the end of the bone without making what are actually large changes in the size of bones or anatomical features such as joint structures and tendons.

For interest, work in ways of accomplishing things that don't use his hands: maybe turning lips into knobby graspers is much faster than changing bone, and can be something kept on since it doesn't affect his feline powers (might even be an improvement without any downside).

The tail could also be used to grasp large things.


Why are you assuming there's nobody else to help? I think it will be much easier if you have a situation where you have three people, the victim, the were-jaguar and a doctor. Transport is available, it doesn't matter if the were-jaguar is weakened with blood loss. It does matter if the doctor is thus weakened, though. Thus the jaguar can give more blood than the doctor could.

  • $\begingroup$ If there's another human around, it would be a MUCH better idea to use their blood. The only reason they'd risk using animal blood is if the other choice is certain death, right? $\endgroup$ – Arthaey Angosii Mar 27 '15 at 6:54

Third Person doctor/helper is a non-biological Person (Robot), or a sapient non-mammal, or a human with a very serious blood bourne infection, or some blood toxicity Thing. All very good reasons not to use their own blood


The jaguar should try and be frustrated by his inability to find a vein and do the IV.

The dying woman (a pediatrician) tells him that they used to give fluids intraosseously when they could not get a vein on the kids (true; check wikipedia).

The jaguar does a "cut-down", opening a bone with his teeth and plugging the needle with the fluids into the exposed marrow space. One thing a jaguar does have are teeth capable of opening a bone. This is gory and visceral but would work. She gets infected with a bite, not his blood; hopefully that does not matter.

Oh - he needs the IV fluids but if he has the IV equipment he probably has a bag or 2 of saline. Maybe a rapid infuser pump too. This scheme sidesteps antigenic issues with animal blood too.


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