Well here I am again attempting to wrap up this series on rattlesnakes. I just published number three last night, and this morning I discovered a comment on it from my old Marine Corps buddy that lives in Rosemond, Ca. In his comment he stated that his daughter and husband have just moved to Lancaster and in the last two weeks have killed two Mojave Green Rattlesnakes on their front pourch. Wow, that is scary the Mojave has a combonition of haemotoxic and neurotoxic venom. Neurotoxic as I will shortly explain is the most dangerious of the two. The Mojave is probably the most dangerious and poisionious snake by volume in the country. Nuff for now, will get in to the meat of the story now. Just a warning to Karen, watch your toes and legs kid.
In the winter months the tempatures do rise high enugh to allow the rattler to function. In order to survive the cold months the animal has adopted the form of hibernating.
Hibernation can take several forms, in warmer areas it may be just for short times, days or even weeks at a time interspersed by warmer spells, when they can emerge and function for a time. these species shelter singly or in small groups. In colder areas, a more or less continious hibernation occors, sometime for many months. the Timber rattler in the northern latitudes hibernat for up to seven months out of the year.
Where the density of the snake population is high and sutiable areas of space ar rare, rattlesnakes congereate in large dens, located in deep crevices or holes and galleries in the earth. several hundred rattlesnakes may use the same den. Many of the large dens have been located and destroyed in the past, so the hugh numbers recorded in the past may never be seen again. the Great Basin rattlesnake andthe northern Pacific rattlesnake are thought to form the largest aggregations, exceptionally up to 1,000 individuals. Other groups that hibernate together are the western diamonsback, the red diamondback and the speckled rattlesnake. these are found in smaller numbers of around fifty to a den. In the east the only species that seem to group together is the timber rattler with 200 seeming to be the max.
Often after emergimg from hibernation they are found basking in the sun for a few days. this is called “lying out”. Traditionaly the large rattlesnake hunts or “roundups” are held during this lying out period to ensure the maximum number of snakes slaughtered. (mans way of destroying nature in the name of fun, my editorial for the day).
Most rattlesnakes appear to have home ranges – areas in which they can predictably be found. Home ranges may well be far from where they hibernate (logically, two hundred snakes could not share the same hunting area). Some snakes may travel great distances from their dens to a home range. Having a home range proboably helps themt feed more efficently because they know the patch of ground they live on and can predict where food can be found.
After tempature regulation, feeding is the next important rattlssnake activity. their feeding habits have to a large extent beeen the driving force behind their evolution of their venom apparatus and the rattle.
Since the most specilised sense organs, the heat pits evolved to detect the presence of warm objects, it is hardly supprising that warm-bloodes prey is the most likely food source. the most important prey therefore is small mammals. No species do not eat mammals and many nothing else. It is unlikely that they have any paticular prefernce as long as it will fit in to their mouth. Taken overall it is estemated that 85 percent of their diet is small mammals. Of course their most common prey will be what is ever prevalant in their area. This will include mice, kangaroo and wood rats , and slightly larger for the larger snake, ground squirrels, prairie dogs and cotton tail rabbits. Only some of the larger snakes can swallow the adults of some of the fore going.
Birds form the second largest group of their diets. These would be the ground nesting birds and their eggs and chicks. Although some rattlers have been known to crawl into low brush and srubs after roosting birds.
The remaning five percent of the diet consists of amphibians, lizzards and other snakes. It must be noted that all of these are indeed cold-blooded also and are not a really viable source of heat for the heat- pits to home in on. A basking lizzard my give of a slightly warmer target than the surrounding area but most likely these meals are just targets of chance.
METHODS OF HUNTING
Like I have alread stated next to tempature control, hunting and feeding is the largest porportion of a snakes waking hours. Not only because they eat large numbers of prey, but because hunting and stalking is time consuming. Rattlesnakes are sit and wait hunters. Many nights and hours are unproductive a snakes sucess relies on its patience. So lets take a hypothetical snake and follow it on a nights hunt.
Activity begins as the sun goes down and the ground begins to cool, this is when the rodents become active. Our rattler rouses itself and makes for a place where it is likely a fat chunk of meat may make a aperance. Once in position the snake puts several bends in its neck ready to strike and settels to wait. After several hours nothing has apeared and the ground begns to cool and the hunt must be abandoned for the night and it retreats for the night ot a place of saftey and some warmth, appetite unsatisfied. This may happen for several nights, sometimes even weeks before prey materilizes. Evolution will have told the snake when to seek a new area for food.
When prey does appear the rattlers formatable array of sense organs jump into play. It may be alerted to the presence by vibrations caused by the activity of its quarry. It starts by flicking its tongue, picking up the sent molecues in the air and transfering them to the Jacobsons organ in its mouth. detecting the source of the vibrations, maybe a mouse, it uses its heat pits to locate its position. Even if the mouse senses the snakes presence and freezes its body will still give of the heat neded to pinpoint its exact position. If the mouse is out of range the snake will either wait for it to move closer or will edge closer in the rectiliner motion mentioned earlier. It may stalk the mouse like this untill with in range. Then with lightning speed the rattler strikes, with mouth opened wide driving its fangs deep into the chest area. Closing its jaws it then pumps the venom in to the victum. The snake them recoils maybe opening and closeing its jaws several times to realign its jaws. Meanwhile the mouse will stagger around getting weaker until it colapses.
After a few minutes the snake begins to flick its tounge over the ground where the mouse was to locate it. Now it searches for the head and begins to swallow it by drawing it in with its fangs one side at a time until it reaches the snakes throat where muscel contractions finishes the swallowing process. By this time the digestion process is well under way due to the enzymes in the venom.
Rattlesnakes will eat road kill more so than other snakes, as they are programed to eat already dead kills due to their venom. ( I belive I mentioed the series of photos of a rattler swallowing a large fish it found on a river bank). They have been reported of eating animals dead several hours or days.
VENOM: COMPOSITION AND EFFECTS
Rattlesnake venom consists largely of proteins, mainly in the form of enzymes. There are at least 10 diffent enzymes in all snake venom and as many as 20 in some. Enzymes cause biocemical reactions inside and outside animal cells, effectively breaking them down. In effect, snake venom is a very strong solution of digestive juices that can be injected into a animal by biting (as a note the sting of a scorpion is much the same). Snake venom varies from species to species by composition, its effect also differs.
The strength of a snakes venom depends on several factors. While the venom of some is more potent than others, the volum of a bite must be considered, this is called the “yeild”
Venmous snakes produce a cocktail of venom contaning more than one vareity, althouth one type usually is more predominate. Snake bites vary according to which type of venom is more predominate.
Most viper venom acts mainly on the blood and citculatory system of their prey. This is known as “haemotoxic” venom. the other works on the nervious seystem and is known as ” neurotoxic” although it is dangerious to generalise, Neurotoxins tend to act quicker than haemotoxins. They also produce little pain at the site of the bite, but cause breathing problems and pralysis. Hametoxins cause imedate pain at the site of the bite , massive brusing and internal haemorrhaging, followed by permante tissue damage.
Now I am going to vear away from the books I have been quoting and go to a report I found online on the National History Magazine web site. the article was from 2000. The article stated that previously people bitten by rattlesnakes which had a predominatly solution of haemotoxin venom were almost always expected to live, Especillay after the 1930’s with the event of antivenom ( produced by injecting horses with a small dose of venom and allowing them to produce a natural resistance to it). It stated that a person has at least a two hour window to get treatment? Neurotoxins however dosn’t allow such leasure because it blocks nerve impulses to muscles including the diaphragm used for breathing, (the article recounts several difftent cases if you wish to prusue them). Neurotoxin bites can cause immediate shortness of breath, weakness or paralysis of lower limbs, double vision ect. and death can occour in as little as ten minutes, usually due to disruption of breathing.
Now for the part I find destressing. Of the fiveteen species of rattlesnake found n the United States at least ten have been verified as having neurotoxins in their venom. Untill recently (2000) however the low levels of these chemicals in the overall mix were not considered much of a threat to humans. In this report there are indications that more neurotoxins in greater consertraton are showing up in some of the other ratlesnakes than in the past. The question is, are the Mojave rattlers inter -breeding with the adjecent rattler populations increaseing their potinecy? Or are the other snakes developing a stronger mixture for changing hunting pratices? I guess the debate in the scientific population is in the air. It just looks like a bad deal is just getting worse.
Now, I found this info on google under rattlesnake bites. I invite you to explore further on your own if interested. Also when there, look for a site “Justins snake bite” it recounts the experence of a thirteen year old, on a group hike in Yosmite and the resulting pacific rattlesnake bite to his hand. he tells of his ordeal and the $700,000 worth of treatment that resulted. he has a propority claimer on his site so I will not quote his story, but look it up, it is interesting.
I am not going into the rattlers defense tatics, as they are self evedent. As for repoduction lets just say it take two to do it. Some females remain in the vicnity until the first shed at about six weeks and others abandon them at birth. They are born ready to function fangs and venom and all. they do not get a rattle untill sheddng as told in the first installment of this book, length blog.
I hope you have enjoyed and gained some insite into this amazing creature. and you will give it the respect it needs and deserves. As I said long ago, he does not set out looking for you and will avoid you if you let him. When on his turf be respetful, live and let live.
Well like Porky Pig always says “Th Th Th That’s all folks”