Is the blood by my window from a person or animal?

[Curare]

So how do you see DNA with a $1000 visible light microscope? We're talking about DRIED samples as well. That nice fluffy erythrocyte looks a little different when you swab it off of the concrete.

I've seen things as small as DNA but it was with a $10,000,000 Zeiss (which I broke, but that's another story--OK it just happened to break while I was using it. You'd be amazed at what kind of repair service you get for a $10,000,000 appliance. The repair dude flies in from Texas ASAP. Very nice.).

You know what--if we are concerned about a human vs. an animal, ASSume it was a human trying to break in. Your great dane did well.

 

[OpenRoad]

I tried posting this on the 1911 forum but they closed it saying it was not on topic. I still disagree with that because it is directly related to my personal safety and defense, but it is their forum.

They got some not too bright mods their, so I try to stay out of the general discussion type forums whenever possible.

 

[ccw007]

It has been a few weeks and nothing else has happened. Looking at the blood trail it looked very human to me, so I have made several changes to the house and our normal routine. My wife said that to get anymore secure you would need to be at Fort Knox .

 

[Double Naught Spy]

I think PaulBK's kids was seeing chromosones, not DNA.

Several folks seem to think it is fairly easy to separate human from animal blood. I laugh every time I read statements like that. Why? Humans are animals. DT Guy says his wife says fresh or fixed blood can be morphologically identified visually under a scope by a trained person. That may or may not be the case and even if it is, that isn't how samples are identified these days since there are better forensic methods that don't rely on the blood remaining pristine fresh or fixed. By the time of the post, the information was no longer valid for this situation anyway.

So we have folks chiming in on being able to clearly see the differences between chickens, cats, and dogs on slides professionally prepared for teaching labs. Great. Good for you folks. The process of identification, however, is not one of simple matching, but of matching and exclusion, here based on visible morphological traits. So you have a blood sample and you know it is not a cat, dog, or chicken. Is it a raccoon? 'possum? cow? goat? pig? elephant, monkey? How does human blood differ from that of other primates? When making the identification, what traits between species are similar or identical? What are the traits of blood that are going to be diagnostic as to species? You have to know your comparative universe.

The notion of just being able to eyeball some blood under a scope and make an identification really is a huge over-simplification of the process that would need to be undertaken to actually make an accurate identification.

 

[River Wraith]

I'm betting animal. Please let us know what you find out.


Oh yeah, can't you distinguish human blood from animal blood by the number of chromosomes?

 

[poe_9999]

In the last picture it looks like the blood droplets are sparse and random over a 10-14 inch pattern. It also looks like the area where this blood was found offers some protection from the wind. This leads me to conclude that sparse dispersal pattern was cause from the blood falling from a substantial height, with the source having a little bit of movement. I would say this blood pattern was cause by a cut on someone’s hand, and the person was making an attempt at first aid. If the person or animal were just standing there bleeding it would be a denser splatter pattern. It also looks like the blood drops are pretty circular. If some force were acting on the blood causing it to move that much of a horizontal distance the drops would look more elongated. Now if this was an animal it was a very large animal. The highest part of my black lab that could possibly drip blood is 22inches (noise). I don’t think that splatter pattern could occur from a distance of 22 inches. Now for instance if a 6ft man cut their hand and was giving themselves some type of first aid the blood would be dropping from a distance of about 45 inches. Which I would say is very consistent with the splatter pattern.

Now looking at picture 2 I see that the bleeder navigated around the table and chair. Now if this were a small animal (dog or smaller) would it have navigated around the table? I think not… My dog would have walked a straight line between the legs of the table. The picture also gives the appearance that the legs are spaced decently. I do not see a reason why an animal would walk around a perfectly navigable route.

Now when a person steps the ground stops their downward acceleration. While the blood on their hands has a little bit of momentum. If an adequate amount of blood existed on the persons hand /animal fur it would fall off their body when their foot impacted the ground. Now if you were to navigate that path would your steps be able the same distance apart as the blood droplets. I think so…

I would say it was a person.

 

[cpileri]

know anyone with a microscope?

Human blood cells are pretty identifiable under a microscope.
Might be a way to check...
C-

 

[yodaddy]

Maybe your looking for the anwser backwards

Why not take it the other way. Go to your local vet and say you want the animal blood tested. If it isnt animal blood, im sure they will know. Sounds like a simpler course of action too...

 

[abaddon]

Human, not animal.

Animals have fur over their whole bodies. They also would not stick around for very long after being cut. Little shards of glass would not make a very deep cut - by the time the fur had gathered enough blood to start dripping an animal would be far away from your house.

Keep in mind that animals do not understand first aid. They will run away first, then lick their wounds. Humans sometimes do it in a different order. Add to that what poe 9999 said and I think it's pretty definitely a human. But it sounds like you've done all you can to protect your loved ones and yourself - good job.

 

[Ali]

a bird probably hit your window, same thing happened to me.

 

[ccw007]

Update

The local Vol Fire dept was broken into this week. They are about 2 miles from where I live. According to the local news there have been several break-ins in the area. I was also talking to a neighbor and they thought someone was messing around their house a few days ago. It is sad because this is not a bad neighborhood. I am sure this was a person now. Maybe they will remember I have big dogs.