장음표시 사용
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during this process. on open. plain terrain with smaller Geld Objecis than the wave tengili, the receiving antenna should be held in a vertical position hecause the objecis cannot shadow or disturbthe signat. In a forest, or in the fiet d with objects of a comparatively large si Ze, hori Zontal positionis more appropriate to measure the hori Zontalty polari sed component of the signat S ZEMETHYl 995). WΑDA et ah sl 9 l) used a simple television antenna which could not receive any signat in the extreme case when the animal supplied with the transmitter moved into a hole.
The transmitting antennas are almost exclusively omnldirectionat, flexibie, teston or plastic coaledwhip antennas. They are implantable into the hody cavlty of the snake, somelimes in the intestinattraci, when the antenna is coited around the transmitter. EVen so, an antenna in the alimentary canaldisturbs very much the normal digesting process, causing vomiting or starVing. The transmitter oriis antenna, on the other harad. can also he clamaged by the digestive enZymes REINERT l 992). Thesi Ze of the antenna implanted into the snahe depends also on en viron mental conditionso in diverse
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rocky habitais, for instance, it is recommended to use a longer transmitting antenna in Order to in- crease the output performance. The limit is, of course, the siZe of the gi Ven Snake species. In ourcase with the meadow vi per os an average hody siZe of 40 cm, the maximum antenna tength withthe transmitter on ibi MHZ could not exceed 8-9 cm sabout 20R of hody tengili). The transmittingdistance was accordingly shori, although the manufacturer gave a reference to l000 m. good quali ty signat s could generat ly be received only hom 200 meters. Considering the relatively smali home range of this insectivorous viper, this was stili sufficient for Our study, however the whip antenna caused some problem for US. The antenna of the transmitter is usualty a flexibie plastic coaledcopper Wire, whicli is put under the skin of the snake ventral side), directed towards the head . parallel to the vertebrat column. In Our study about T weeks after the implantation. studied snakes were mund in the Geld having pierced their skin by the blue coaled antenna wires. The wire pierced theskin at about the half tength of the animal. on the fide of the helly, and cca. 2 3 cm tength of the antenna was sticking out of the body. The snakes were Otherwise healthy, with normal defending bellaviour and good condition. We put the antenna back under the skin and fixed the wound withan adhesive surgical band. we thiis that the antenna wasn 't sufficiently flexibie and sostly coaled this may have been the reason for the uncon Venient injury of the snakes. The cover - The cover of the transmitter silould fulset severat criteria. The original materialmust he water resistant, strong but easy to fhape, removabie sin the case of battery replacement), and protective sto encapsulate the vulnerable paris of the transmitter). It is important to with standitie digestives and other body fluids in the case of intragastric and intraperitoneat insertion, and also
Swax is a Sofi, water resistant, gentie to tiSSues, eaSy to Shape, sinooth materiat, ideat for transmittercoating. The parassin component increases iis resistance and strength.
There are severat methods of attaching a radio transmitter to a snake's hody Table 2). The method to be used depends on the aim of the study, whether we Only want to observe the move ments of the animal, or collect physiological data af well. In the first case the transmitter can simply be attached to the s kin furface, whereas in the other case the transmitter silould be placed inside the body of thes nake. In the following chapters the different methods are shortly described. thenit continues with the problems of implantation, including immobili sation, an aesthe Sia, Operation and post-Operational control. Apari hom attaching the transmitter to the hody surface, there are three different methods of 'implantation V widely used in the literature: force- eding into
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Crotalus milchelli Pyrrhus Oralty inserte l
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AuthorSSpecies Attachment Anaesthesia
A radio transmitter attached to the snake's hody sursace may prove to he useful in few cases and sor stiori study periods Only. GENT and SPELLERBERG sl 993) turned to this method prompted by the strict nature conservation regulations in Creat Britain and the enclangered siluation of their study objeci, the sinooth snake Coronella austriaca). The transmitter was placed on the snake he-hind the cloaca at the sirst section Os the tali and fixed by glue and medicat tape. This method couldfix the transmitter sor a period belween 0. 0J-9. Tl days. During the three-year study of GENT and SPELLERBERG Dona the 39 marked speci mens 6 lost the transmitter and P got caught in the vegetation due to the 'package'' on the tall. The conclusion is that this method can he recommended on lyin the case of very shori term observations and when the implantation represents a hi gli risk of loos-
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ing even one single specimen. With an externalty fixed transmitter, almost permanent monitoring is necessary to preverat any problem ariSing sto in the movement difficulties. This, On the other hand can cause heavy disturbarices and likely changes the natural bellavi our of the study animal. Another method os attaching externalty the transmitter is protected at least against the loss ofit. A thin nylon thread ted subculaneoiasty through two incisions on the subcaudat plates bellind thecloaca can sex the transmitter to the vertebrat column CIOFI & CHELAZZl l 99 l). The subcaudat diameter of the snakes is smaller than the maximal hody diameter, so a transmitter sinati enoughless disturbs their movement. The method has a great ad vantage due to the following reasons: sorthe replacement of the transmitter sor the batteries) there is no need os surgical treat ment. Accord- ing to the authors. it can also be used in Smaller species.
stomach has a similar effect to the snake's bellavi our than that os a swallowed prey. Force- sed snakes have also chosen a substrate with flightly higher temperature in contrast to those without 1 ood. Their normal laeding heliauiour, however was out os cycle and they spent more time without mod, lying on the Sun. Some observations showed that the transmitter in the stomach cara alter
beginning of hibernation may also he due to the effect os transmitters. A too sinali transmitter, howe 'er, can eas ity go through the whole intestine. and eventu alty leave the snake with the excrement
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l98J). Sewing up the wound with one or two suture could also be recommended. implantation carried out just hemi e shedding is not recommended. since the peeling skin can remove the surgicalcover anu heiace reopen the wound EATHERHEAD 9 ANDERMA l 984). Even l. monilis aster theoperation, shedding difficulties may appear around the wound. Transmitters remaining longer in the snake may be encapsulated in tissues. but removal does not seem problematic WEATHERHEAD& ANDERRA l 984). Although it scenas that the most effective method for attaching the radio transmitter to the snake is the subculaneous implantation, with smali hody si Ze it stili cara cause troubles during the movement or alter the bellavi our of the animal.
aled at the front of the mouth and is freely movabie frona one fide to the other. An other speciat anatomical Dature is that only the right iobe of the lung is de-veloped to the two-fifth of the total hody tength, whereas the lest iobe is almost missing. Siaakes have no diaphragm. their cerebrat regulation is weak. Spinalneuroregulation has more influence: metabolism is generat ly low and depends ina great extent tapon the en Viron mental temperature. During the anaesthesia of snakes ali these an atomical features must betaken into consideration. Due to the low metabolis in the influence of the an aesthetics bullds up slowly, and the awakening may be de layed as well. In order toachi eve total immobili sation of the snake the spinat reflex must be inhibited. butthis - e specialty in the case of a large ly vegetati Vely neu roregulated animal
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may cause death in extreme cases. An aesthesia may block the muscies heiweenthe ribs, and hec ause snakes have no diaphragm it might sto p the respiration
Inhalation agenta - The sirst reporis on anaesthesia of snakes were publis hed at the end of the l930s. They were ali connected to research on the Venom glandS and Venom production of pol sonous snakes CLARK l93J. KELLAWAY l93T, TAIT l 938). In these experiments main ly chiorO- forin, and later a mixture of ether and air were used as an inhalation anaesthetic agents, whicli madethe animal motioni ess during the operation of the Venom gland . Ten years later a new inhalationagent called Fluothane or Halothane C2HBrClF3. 2-hromo-2-chlorΟ-l, l, l-tri fluoroethane) appeared on the market. This volatile fluid has sive times higher influence than ether. it is not inflammabie, and does not irritate the respiratory tracks HACKENHROCK Ω FINSTER l 963). It is heavier than the air whicli needs to he considered when applying and heiace it is important to pre-vent the snake listing iis head out of the gas. For a s hori anaesthesia 5-20 minutes) of hig ratilesnakes abolit 5 cm' Ultiothane proved to he enough, and awakening did not take more than l0 minutes. REINERT and CUNDALL sl 982) invented a simple technique sor anaesthesia of snakes. Asmali piece of textile saturaled with Halothaiae, Methoxyssurane or Iso urane is placed togetherwith the animal into a glass tank, and when the snake is fleeping it is pulled into a plastic tubewhicli is plugged at one en d by a cotton with anaesthetics. Inhalation during the operation can becontroited simply by removing the cotton plug when neceSSary. For implantation of the radio transmitter we have also successsul ly used Halothane as an inhalation agent. In our experiments UIVLRI & KORSOS l99T, VIVARI et al. l 999) we used a properan aesthetic equi pinent appeared in human and veteri nary medicat treat ment. It was a litile bit modi- ed for snakes, i. e. instead of the inhalation mask used for large mammais, a thin rubber membrane was placed at the end of the inhalation pipe with a narrow hole in it. The head of the smallsi Zed Meadow viper Vmem ursinii ria ostensis) was placed here tantii anaesthesia took effeci. Atthe heginning os the operation pure Halothane, later a mixture of Halothane and Oxygen waS gi Ven, the ratio depending on the status of the animal. The inhalation pipe was trans parent for the continu-ous controi of the snake. The operation simplantation os a radio transmitter) lasted about 20 minutes, and illo ing the fixation of the wound the snake woke up almost immediately due to the pure oxygen gi Veia. The technique also worked welt with the common Grass snake tria natrix)
histro lon contorii ix. The method was tried in ββ cases on 38 specimens os snakes without a single case of mortali ty. id immobilisation and locat cinaesthesici - It is a widespread method to coob the snakesbefore anaesthesia, hecause it makes the handi ing of animais easter. WEATHERHEAD and ANDER KA
l 984) put the snakes into a refrigerator of 5'C for 45 minutos bufore injecting the agent s80 mgIkgKetaset) intramuscularly in mur different paris of the bo ly. When anaesthesia took effect theyplaced the snakes back in to the Didge sor another i 5 minutes just be ire the operation. NAULI EAU l98J) also placed his animais Aesculapi an snakes, Emphe longissima) into β' C refrigerator sorone hour heire injecting the locat anaesthetics 2R Hostac in or Laocaine S 2). Aster l5 20 minutes
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mglkg) during the Operation. Controi sis anaesthesia and summary - The work of BETZ sl 962) initiated a new period in the anaesthesia os reptiles. He gave a comprehensive summary of the effecis of the different agenis and also evaluated sor the first time the bellavi ourat criteria of the controi os anaesthesia. It was al- ready known by earlier authors sBRAZENOR & KAYE l 953. KAPI AN & TAYLOR l95J. KARI STROM& Coog l 955. TAIT l 938) that the lack of certain spontane movemenis, like the longue reflex, or of the reaction to externat stimuli, like the tali reflex, are sigias of deep anaesthesia. During inhalationos ether, spinat reflexes were used for control. but this has iis disad vantages as mentioned earlier. According to BETZ sl 962) it is enough to get an anaesthesia untii the tali reflex disappear. the lachos longue movemenis is a sign of a deeper influence whicli is not necessary. M ADSEN sl 984) hadaia opposite opinion he immobili sed the snakes with the injection os Ketalar si00 in kg) andRomptin 20 mglkg). when the longue reflex had at ready di sappeared the tali reflex was stili present. In order to avoid overdosis later he only used locat anaesthetics Xylocat ne l6 m kg). Among the inhalatile anaesthetics ether is inflammabie, chlorosorm is cardiotoxic and inhi- hiis livor and hi te su iaction. It proved to he carcinogen in human medicine, too. Halothane and Methoxysturane are four to eight times more effective than chlorosorin and ether. and furthermore they do not irritate the respiratory system. They are the most recommended agenis in herpetologicalanaesthesia sAIRD l9J8). There is a good summary on reptile anaesthesia by MCDONALD sl 976). During the implantation Os transmitters into snakes we recommend the application Os Halothane as an inhalable agent and the use os a proper anaesthetic equi pinent. It has the di sadvantage of heing bound to a veteri nary hospital . hut the possibili ty of the controi during the whole operationpuis it in balance. You have to kecp in mind. however, that ali the anaesthetic agenis have thedanger that in case of Overdosis there is no antidote against them BETZ l 962).
Controisollo ing imPlantation It is necessary to devote a severat day observation period to study the animal aster the surgical operation. The tength of the period depends on the implantation and immobili sation technique u sed . hut it should last at least l-2 days to
in the case of large snakes, since their movement rare ly reaches the magnitude ofkilometres, whicli is stili eas ity covered by walking. In most studies the relative
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undisturbance of the animais is a primary consideration. whicli can be tested against sudden movement sescaping). or long hiding. Ideatly, the purpose is to locate the snake's position without iis perception. Thi S, Os course, can change byspecies and en viron mental conditions. In a study by TIEBOUT and CARY l98J) the position could be identified by 0.β metre precision hom a distance of 3-6 metres without actualty seeing the animal. Direct trac ingIn this case the observer follows the strongest radio signat untii the animal eventuatly can be seen and Dund. This technique is primari ly used when the
habitat terrain cloes not allow remote sensing and the researcher has no ideawhere to search for the snake and lience location staris hom a large distance. Direct tracking can suppon detailed visual bellavi oural andior ecological observations, when the disturbance of the animal is not so important. Tricingulatiori Triangulation is based on signat search hom two or three more-Or-leSS rectangular directions. First the exact direction of the strongest signat is determinedand then the potnt of intersection gives the locali ty of the transmitting animal. Since handhold antennas used for radiotracking snakes have an accuracy of ca 5 degrees, the estimated locali ty of the animal is actualty not a poliat but a s mall
ments was compared to the fide of the error polygon lf the first was sinalter. thenthe movement was considered Zero, hecause it could not be decided whether itactu alty happened or it was the error of the method. With this concepi, tinfortunate ly. the relative ly smali dat ly movements are almost impossibie to track. Actuat location os a snake with a radio transmitter is usualty the result of the combination of the two methods: direct tracking and triangulation. Search is stat ted far away with a liandii old Yagi antenna. where triangulation is usualty in- applicabie because of the large distance and the shadow effecis of the terrain. The error polygon would also be too large and even two rectangular meas uring potnis are too remote frona each other to walk. Exact direction determination is difficult.
Approaching to the locality the signat is strengthening and the triangulation
method hecomes easter. From a closer distance the Yagi antenna hecomes clum-sy, and precise location is impossibie hecause the signat comes frona everywhere with the fame strength. A smali loop antenna can hel p in this case, and the sna kewith the transmitter can he mund step by step almost centi metre by centimetre. Isso exact location is not necessary, the square metre that the snake occupies is eas
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Devel opinent of research technology in radiotelemetry of Siaakes was ac- compani ed by forming a conceptu at system for the description of their activi ty. There are numerotis definitions in the literature describing the range of animal move ments. MOHR and STUM PF sl 966 considered the terins home region, homerange, home area to be Synonymous when individuals remalia around , and use a home more than 24 hours. In their opinion the territories make part of the homerange, sOme apparently fili out the entire home range and others consist of smallareas with in the home range. The ho me range of snakes and movements with in it
movements of snakes: habitat and substrate preference, hibernation siteS, moVement frequencies, and reasons for moving. When identibing an exact place