Double Naught Spy
Sus Venator
I put this together for consideration. In a recent thread, http://www.thehighroad.org/showthread.php?t=570979&highlight=hog+shield, the reason for a boar's shield was said to be apparent. The video in question shows two large boars engaged in a duel before being cruelly shot by "hunters" who had no interest in a humane death of the boars. However, that video does provide of very good documentation of damages inflicted in boar battles. The video got me to thinking about what a boar's shield is really for and why they have shields. I read though a bunch of materal on numerous forums and basically what I came up with is a bunch of undocumented beliefs about the boar and its shields. These beliefs seemed to be misconceptions that didn't actually fit any real information. Feel free to critique...especially if you can come up with some documentation for whatever you think is wrong.
Those of us who have shot boars have sometines assessed the condition of our kills and noted various traits such as body scarring that appears to be battle damage. Then there is the boar's shield. It is often described as a thick layer of a tough tissue that protects the boar's vitals. Here, and on many of the hog forums, the shield is stated as being scar tissue that forms as a result of injuries suffered in battles with other boars that thickens and hardens over time. Some folks claim the shield is actualy cartilage, but that is often disputed by those who know that the shield is scar tissue. Some claim it is a combination of scar tissue and cartilage. Virtually, everyone says it is for the purpose of protect the boar's vital organs. Most of this common knowledge isn't supported by reality.
The shield is present on the dorsal (upper) and lateral sides of the rib cage and can run from the neck along the sides of the boar and may extend to the last rib. The shield tends to be thickest over the shoulder area which is also the area where the shield extends the lowest point on the boar.
http://www.google.com/imgres?imgurl...&ndsp=13&ved=1t:429,r:8,s:25&biw=1023&bih=622
So I was watching the above video and it dawned on me that both boars were inflicting considerable damage on one another in locations where the shield was not present. In looking at over videos, the same pattern of attacks is evident.
http://www.youtube.com/watch?v=cKSKXTHlMT8
http://www.youtube.com/watch?v=v3ddDNGXdAM&feature=fvwrel
http://www.youtube.com/watch?v=Rk9UmLk0ziE&feature=related
So sense the shield is scar tissue that is supposed to form as a result of damage inflicted from battle with other boars and grows thicker and harder over time, then why do we no see shield growth on the low side of the body where the boars get considerably cut up? Look at the video and you will see bloody wounds in the lower neck, chest forward of the front leg, leg, and chest behind the front leg. While I don't see significant damage further back, the area of the gut forward of the rear leg also appears to be a location that is often struck.
Keeping in ming that the shield is located mostly high on the body where there is a lot of musculature, the sheild does not cover the chest or ventral areas. In the case of the chest, there is much less musculature than is present on the back where the shield is located. When the hogs battle, they continually try to get their heads and particularly their tusks in a low position in order to be able thrust upwards their tusks into the unshielded areas of their opponent. The one key vital organ in that are is the heart. It is not particularly well protected from these attacks, location being quite low, sheilded by ribs, thin muscle, and skin and hair, though the leg does block some lateral access to it. Further back, there are portions of similarly located lungs and ribs. In other words, the shield isn't protecting the heart, lower side of the lungs, or the liver from attack by other hogs in the area that is most commonly damaged from such attacks. That seems very peculiar.
If the shield grows where it does as a result of scar tissue from hog battle injuries, then we should see extensive shield growth on the underneath aspects of the boar. No shield develops there.
Another problem is that scar tissue grows as a result of tissue damage and is very localized. Scar tissue does not grow or spread to cover large areas of undamaged tissue. However, hog shields to cover large areas and quite surprisingly, skin tissue above the shield does not always show extensive scarring and in fact large areas of skin over the shield may be unscarred (which I have seen). If the shield is scar tissue, then what damage is being done to the hog that results in shield growth in areas for which there is no damage?
Now consider this. Shields grow on both sides of the boar and are present in the same place on different boars. Battle damage may occur in some of the same basic locations, but between individuals, but the amount and extent of such battle damage can vary quite a bit, but the shields don't. In short, the notion that the shield is scar tissue does not make sense. If the shield was scar tissue, it would be quite irregular, differentially distributed based on where an individual hog has suffered damage, and irregular in depth depending on how deep the wounds were. This is not the case at all.
Not explained by the scar formation hypothesis is why the shield doesn't form anywhere else. The underneath belly, chest, and neck areas seem to be the primary areas of attack and as shown so well in the first video, suffer lots of damage and would have lots of scarring, but don't develop shields.
Given the uniformity of growth and location of the shields, it would therefore seem that the sheilds do not grow from scar tissue. Instead, shield growth is going to be genetic, potentially horomonally influenced. The fact that the shield exists where there is no tissue damage is because the shield does not grow from the dermis (living layer of skin) or the overlaying epidermis (dead layer of skin). Turns out, the shield forms in the hypodermis or subcutis which is a layer of connective tissue anchoring the dermis to the underlying muscle. A critical component of this layer is collagen fiber. In boars, this layer is really transversed with collagen to form the shield. In other words, there is a lot more collagen fiber found in the shield area than is found in the hypodermis elsewhere on the body. See http://www.sinclairresearch.com/Dow...Porcine Integumentary System Model-Part 1.pdf
So folks have noted that when they boil the shield that they get a gel forms. What they are doing is rendering glycerin from the collagen through hydrolysis and glycerin a gel-like substance.
While the low areas appear to be the primary points of attack, that isn't to say that the shield does not provide protection. In watching the videos, you will see the hogs make high strikes as well, raising their heads up high and swinging/thrusting sideward and even sometimes in a slightly downward fashion and those strikes do appear to be hitting the primary shield area. A buddy I hunt with says that he has seen this tactic used by a boar to drive its opponent to the ground where it is no longer able to fend off attacks...which is very interesting.
Given that the shield covers part of the shoulder blade, shoulder joint, and substantial back musculature which covers the ribs, the shield does not actually seem to function to protect vital organs from other boars. Keep in mind that the boar doesn't need shielding protect its low vital organs from attack on its ventral side that gets a lot damage (see above), so why do the vitals need to be protected from above where they have much more bone and muscle protection already? It doesn't. The shield isn't protecting vital organs from the attack of other boars.
Those vital organs are already very well protected. Instead, the shield seems to be protecting the musculature and skeletal parts necessary for the hog to remain standing and viable for fighting or viable for escape. In other words, if those structures are damage significant, the boar's physical abilities will be curtailed, and the boar possibly driven to the ground where he will no longer be able to mount a viable defense.
In short, the shield appears to have nothing to do with scar tissue except that there may be some scar tissue over the shield in the skin or even in the sheild when it has been damaged in battle, but the scar tissue is does not cause the shield to grow and scar tissue doesn't typically grow in undamaged areas. The fact that the shields grow in the same area on boars indicates that there is a genetic determination to them and their ties to boars may be hormonal. Boars are damaged considerably in battles along their ventral areas that provide the least amount of protection for the heart, lungs, and liver which are vital organs, but no shield grows there. So the shield isn't for protecting vital organs from other hogs. It does seem to protect the shoulder girdle and associated musculature and this area is an area that is attacked during fights, but much less than the ventral areas. These are vital structures, but not what folks would consider vital organs. They are vital to the boar's survival from attack as if significant damage is done there, the boar's mobility and ability to defend itself or escape will be compromised. Okay, that is speculative, but the shield isn't located where it is located to protect internal vital organs from the attacks of other hogs and isn't comprised of scar tissue.
Those of us who have shot boars have sometines assessed the condition of our kills and noted various traits such as body scarring that appears to be battle damage. Then there is the boar's shield. It is often described as a thick layer of a tough tissue that protects the boar's vitals. Here, and on many of the hog forums, the shield is stated as being scar tissue that forms as a result of injuries suffered in battles with other boars that thickens and hardens over time. Some folks claim the shield is actualy cartilage, but that is often disputed by those who know that the shield is scar tissue. Some claim it is a combination of scar tissue and cartilage. Virtually, everyone says it is for the purpose of protect the boar's vital organs. Most of this common knowledge isn't supported by reality.
The shield is present on the dorsal (upper) and lateral sides of the rib cage and can run from the neck along the sides of the boar and may extend to the last rib. The shield tends to be thickest over the shoulder area which is also the area where the shield extends the lowest point on the boar.
http://www.google.com/imgres?imgurl...&ndsp=13&ved=1t:429,r:8,s:25&biw=1023&bih=622
So I was watching the above video and it dawned on me that both boars were inflicting considerable damage on one another in locations where the shield was not present. In looking at over videos, the same pattern of attacks is evident.
http://www.youtube.com/watch?v=cKSKXTHlMT8
http://www.youtube.com/watch?v=v3ddDNGXdAM&feature=fvwrel
http://www.youtube.com/watch?v=Rk9UmLk0ziE&feature=related
So sense the shield is scar tissue that is supposed to form as a result of damage inflicted from battle with other boars and grows thicker and harder over time, then why do we no see shield growth on the low side of the body where the boars get considerably cut up? Look at the video and you will see bloody wounds in the lower neck, chest forward of the front leg, leg, and chest behind the front leg. While I don't see significant damage further back, the area of the gut forward of the rear leg also appears to be a location that is often struck.
Keeping in ming that the shield is located mostly high on the body where there is a lot of musculature, the sheild does not cover the chest or ventral areas. In the case of the chest, there is much less musculature than is present on the back where the shield is located. When the hogs battle, they continually try to get their heads and particularly their tusks in a low position in order to be able thrust upwards their tusks into the unshielded areas of their opponent. The one key vital organ in that are is the heart. It is not particularly well protected from these attacks, location being quite low, sheilded by ribs, thin muscle, and skin and hair, though the leg does block some lateral access to it. Further back, there are portions of similarly located lungs and ribs. In other words, the shield isn't protecting the heart, lower side of the lungs, or the liver from attack by other hogs in the area that is most commonly damaged from such attacks. That seems very peculiar.
If the shield grows where it does as a result of scar tissue from hog battle injuries, then we should see extensive shield growth on the underneath aspects of the boar. No shield develops there.
Another problem is that scar tissue grows as a result of tissue damage and is very localized. Scar tissue does not grow or spread to cover large areas of undamaged tissue. However, hog shields to cover large areas and quite surprisingly, skin tissue above the shield does not always show extensive scarring and in fact large areas of skin over the shield may be unscarred (which I have seen). If the shield is scar tissue, then what damage is being done to the hog that results in shield growth in areas for which there is no damage?
Now consider this. Shields grow on both sides of the boar and are present in the same place on different boars. Battle damage may occur in some of the same basic locations, but between individuals, but the amount and extent of such battle damage can vary quite a bit, but the shields don't. In short, the notion that the shield is scar tissue does not make sense. If the shield was scar tissue, it would be quite irregular, differentially distributed based on where an individual hog has suffered damage, and irregular in depth depending on how deep the wounds were. This is not the case at all.
Not explained by the scar formation hypothesis is why the shield doesn't form anywhere else. The underneath belly, chest, and neck areas seem to be the primary areas of attack and as shown so well in the first video, suffer lots of damage and would have lots of scarring, but don't develop shields.
Given the uniformity of growth and location of the shields, it would therefore seem that the sheilds do not grow from scar tissue. Instead, shield growth is going to be genetic, potentially horomonally influenced. The fact that the shield exists where there is no tissue damage is because the shield does not grow from the dermis (living layer of skin) or the overlaying epidermis (dead layer of skin). Turns out, the shield forms in the hypodermis or subcutis which is a layer of connective tissue anchoring the dermis to the underlying muscle. A critical component of this layer is collagen fiber. In boars, this layer is really transversed with collagen to form the shield. In other words, there is a lot more collagen fiber found in the shield area than is found in the hypodermis elsewhere on the body. See http://www.sinclairresearch.com/Dow...Porcine Integumentary System Model-Part 1.pdf
So folks have noted that when they boil the shield that they get a gel forms. What they are doing is rendering glycerin from the collagen through hydrolysis and glycerin a gel-like substance.
While the low areas appear to be the primary points of attack, that isn't to say that the shield does not provide protection. In watching the videos, you will see the hogs make high strikes as well, raising their heads up high and swinging/thrusting sideward and even sometimes in a slightly downward fashion and those strikes do appear to be hitting the primary shield area. A buddy I hunt with says that he has seen this tactic used by a boar to drive its opponent to the ground where it is no longer able to fend off attacks...which is very interesting.
Given that the shield covers part of the shoulder blade, shoulder joint, and substantial back musculature which covers the ribs, the shield does not actually seem to function to protect vital organs from other boars. Keep in mind that the boar doesn't need shielding protect its low vital organs from attack on its ventral side that gets a lot damage (see above), so why do the vitals need to be protected from above where they have much more bone and muscle protection already? It doesn't. The shield isn't protecting vital organs from the attack of other boars.
Those vital organs are already very well protected. Instead, the shield seems to be protecting the musculature and skeletal parts necessary for the hog to remain standing and viable for fighting or viable for escape. In other words, if those structures are damage significant, the boar's physical abilities will be curtailed, and the boar possibly driven to the ground where he will no longer be able to mount a viable defense.
In short, the shield appears to have nothing to do with scar tissue except that there may be some scar tissue over the shield in the skin or even in the sheild when it has been damaged in battle, but the scar tissue is does not cause the shield to grow and scar tissue doesn't typically grow in undamaged areas. The fact that the shields grow in the same area on boars indicates that there is a genetic determination to them and their ties to boars may be hormonal. Boars are damaged considerably in battles along their ventral areas that provide the least amount of protection for the heart, lungs, and liver which are vital organs, but no shield grows there. So the shield isn't for protecting vital organs from other hogs. It does seem to protect the shoulder girdle and associated musculature and this area is an area that is attacked during fights, but much less than the ventral areas. These are vital structures, but not what folks would consider vital organs. They are vital to the boar's survival from attack as if significant damage is done there, the boar's mobility and ability to defend itself or escape will be compromised. Okay, that is speculative, but the shield isn't located where it is located to protect internal vital organs from the attacks of other hogs and isn't comprised of scar tissue.
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