A TECHNIQUE FOR ARTIFICIAL INSEMINATION IN SQUAMATES
Raymond Hoser (Snakebusters)
488 Park Road
Park Orchards, Victoria, 3114,
Australia.
E-mail: adder@smuggled.com
This
paper details the development and application of a simple to use method of
artificial insemination in squamates of various taxa.
The
benefits are obvious.
This
includes that of breeding specimens not inclined to mate and the ability to
transport semen, rather than reptiles across suburbs, cities, or even states
and countries. In the Australian context this is significant as there are “six
month rules” in most states, making breeding loans of actual specimens
sometimes logistically difficult.
While
most of our work has been with snakes, we have trialled the same techniques
with lizards and found that what is reported here for snakes transposes to
lizards as well.
In
the USA context, the methods make hybrids between taxa simple to achieve, as it
no longer requires the reptiles to mate.
Introduction
(The problem)
All
squamates bred at our facility (elapids, pythons and large skinks), are housed
similarly and subjected to the same annual temperature regimes. This is spelt out in Hoser (2006) and Hoser
(2007).
In
summary it involves 7 weeks of cooling whereby the cage temperature is kept
below 20 deg C at all times (with rare rises above this perhaps if the reptile
is used in a “show” or “demonstration”).
Temperatures do still have a slight diurnal cycle of up and down.
This
is followed by a period of 12 hours a day “full heat” and 12 hours of “night”,
after which the reptiles get 18 hours a day heat or all heat, in terms of the
warmest section of the cage.
For
us “cages” are in fact large plastic tubs.
The
exact timing of the “winter” months at our facility broadly mirrors that of the
wild, but our preference is to run the seasons about 8 weeks (2 months) ahead
of wild counterparts here in Melbourne, Victoria, the end result being our
snakes breed earlier.
For
example in late 2007, our first breeding female (venomoid) Eastern Brown Snake
(Pseudonaja textilis) laid a full clutch of 8 fertile eggs at end
October, whereas the wild counterparts usually lay at end December. Two years earlier the same snake produced 10
eggs (9 fertile)(see Hoser 2006).
In
spring of 2006 (broadly referred to here as July-November here in Australia),
it was attempted to breed Jaffa (Collett’s) Snakes (Panacedechis colletti)
at our facility. The snakes were two
males aged 3 years and a four year old female.
Unless
mating is being attempted, we usually house all our reptiles as “one per cage”
as there are numerous husbandry advantages.
When shipping our reptiles for demonstrations, often day after day for
many weeks, reptiles are grouped with the only limiting parameter being that
the snakes be of similar size, with taxa being irrelevant.
It
is common for them to mate or attempt to mate when in transit, including snakes
of different taxa (Hoser 2005b).
The
males Collett’s Snakes had been held since hatching at the facility of Paul
Fisher (Hoppers Crossing, Victoria) and the female raised for two years by
Scott Eipper and then held by myself for about two years, being hatched by
another breeder.
While
one of the males attempted to mount and mate the female in late 2006, no actual
copulation occurred. At the time it was
thought simply that the male wasn’t trying hard enough, and perhaps the male
may improve with age, as is often the case with snakes.
The following spring (2007), it was attempted to breed the snakes again and there was no success in mating. This time both males tried hard and yet the female successfully avoided copulation. She would flee as soon as the males attempted to mount her.
The
cooling regime the previous “winter” had been particularly “brutal” in that the
reptiles were kept colder for longer (8 weeks under 20 Deg C) and this
reflected across the board in particularly vigorous mating activity across all
taxa.
It
is mentioned here that all the Collett’s had been made venomoid in late 2004,
using the successful method detailed earlier that year by Hoser (2004). In fact all Hoser elapids referred to in
this paper are as of 2007, long-term venomoids.
“Venomoid”
means permanent surgical removal of venom glands from a snake to render it
non-venomous (effectively) harmless to humans for the rest of it’s life.
Venomoids
by definition are neither venomous or dangerous to humans and claims to the contrary
are false.
Venomoids
have the welfare advantage of not needing to be stick handled, pinned, tailed,
or necked, (due to the removal of adverse safety issues), the result being
better adjusted snakes that as a rule lose any urge to attack or bite human
handlers, which is the complete opposite of what is often otherwise seen in
venomous snakes.
For
the purposes of this paper, the venomoid state is known to have no effect on
fertility as long-term venomoids have been bred at our facility (producing
normal healthy (and venomous) young), including Death Adders (Acanthophis
antarcticus), Eastern Brown Snakes (Pseudonaja textilis), Tiger
Snakes (Notechis scutatus), and Copperheads (Austrelaps superbus),
which is all elapid taxa we held in the relevant period (2004-7) for which we
had adult pairs, excluding our Red-bellied Black Snakes (Pseudechis
porphyriacus).
This
includes across several seasons involving the same snakes.
Mentioned
here is that our Red-bellied Black Snakes (2 males and a female) mated and produced
“slugs” in 2005/6, and hence by definition hadn’t bred, but at the time of
writing this paper the female was noticeably gravid again (end 2007) and was
expected to produce young either late in 2007 or early 2008 (also see later
this paper).
In
my experience, normally fertile female snakes that are either ovulating or
about to, are happy to be mounted and mated and yet this above-mentioned female
Collett’s was violently opposed to the idea.
It
was as a result of this apparent exhaustion of ideas or means to encourage
mating that I decided to “step outside the square” and attempt artificial
insemination.
The
theory was simple.
Get
semen from the male and put it into the female.
After
that, the spermatozoa should do the rest!
Analysis
of AI methods used for other vertebrates such as cattle, dogs, sheep, humans
and even birds, yielded two main methods to acquire semen.
One
was “electro-ejaculation”, where by an electric shock causes ejaculation. For several reasons, the idea was thought
not viable in terms of the snakes.
Getting
hold of an “electroejaculation machine” was near impossible or cost prohibitive
and then there was the problem of working out the voltage required to get semen
but not kill the reptile by electrocution.
That
is assuming the process was even possible for reptiles!
The
alternative was to masturbate the snakes to get semen.
This
was the preferred method of choice for most animals including bulls and horses,
who are generally made to mate with a false vagina.
However
the concept of masturbating snakes was unknown territory and one that I could
get no guidance from by any veterinarians or others I thought likely to know.
Hence
the idea of masturbating snakes to ejaculate semen was one that I had to
develop from scratch.
In
hindsight it was remarkably simple.
Over
the last 40 years of keeping, breeding and observing snakes, observations of
male snakes and mating snakes yielded certain pointers.
Most
male snakes shed so called “semen plugs” which are essentially globules of
dried and old semen that accumulate in the hemipenal pockets. Hence I knew that snakes oozed or released
semen at times other than copulation.
This
concept went further when it was realized that sometimes male snakes mount
females, attempt to mate without success and then ejaculate semen over a
female. Alternatively and worst case,
would be a male snake mating that breaks off the copulation and has semen on
the hemipenes.
This
occurs naturally and if one looks at the picture of the everted hemipene in a
male Death Adder on page 19 of Hoser (1989) you will see exactly this.
Knowing
all the above pointers, it was thought that it may be possible to stimulate a
known fertile male snake that has mounted a female to get excited and ejaculate
semen in a quantity sufficient to be collected and transferred to a female
snake.
Based
on observations of the quantity and consistency of semen shed in semen plugs
and observed when snakes ejaculated, it was decided to use a glass pipette or
capillary tube to collect the semen and transfer to the female snake.
These
come in various sizes and shapes and as it happens the first one trialed was
the best. This was a “Kimax-51 1.5-18 X
100 mm straight glass capillary tube” that is sold commercially in 100 tube
lots packed in small glass containers in boxes of various numbers. These are also the tubes of choice for
aviculturists who use AI.
They
suggested these as they are “non-Heparin coated” as Heparin is believed to be
adverse to semen.
The
pipettes were in the first instance hard to acquire as neither veterinarians,
GP’s, hospitals or pathology labs routinely stock them. However science departments of most schools
use these or similar and hence small numbers were readily available, including
in various sizes and formats in order to confirm the best tube for the job,
that being the one just named.
The
first successful masturbation of a snake was when a male Eastern Brown Snake
was seen mounting a female (who was already gravid from him).
The
caudal region was stroked with my finger and the snake was visibly aroused and
attempted to copulate with it.
As
I rubbed the snake (just above the cloacal opening on the side of the base of
the tail), the snake became stimulated and after loss than a minute he
ejaculated semen.
This
was gathered by sucking into the pipette and then checked on a microscope slide
at 400X magnification and the sperm cells were readily visible.
Similar
was attempted with the first male Collett’s Snake to attempt to mate the female
and again semen was collectable from both hemipenes within 60 seconds.
The
second male, also interested in mating the male, but not yet mounted her, was
also used for semen collection.
In
it’s case, the snake simply had it’s tail grabbed by myself as the snake sat in
the cage. The relevant region was
rubbed and again semen was yielded.
This was the first snake actually masturbated without actually mating a
female.
A
Black-headed Python was seen trying to mate an Olive Python and it was removed
from the transport box. The tail was
rubbed (at the same place as for the elapids) and the snake yielded globules of
semen within seconds.
In
other words it was possible to masturbate a snake and get semen.
Taking
the process further, two male Tiger Snakes held in cages on their own and simply
resting were each removed and easily masturbated to yield semen.
With
practice, acquiring semen from snakes (by rubbing the anterior caudal region
above the vent) was easy, and for snakes that were apparently fertile, semen
was now readily available.
In
terms of the AI process, the theoretically hardest part of the operation was
now complete.
In
fact by the method devised, getting semen was now simple and routine and could
be done with an un-aroused snake simply resting on it’s own in a cage.
Please
note that in terms of the venomous taxa used, all were well-adjusted venomoid
(no venom in the snakes) that are handled (by free handling only) for live
shows on a daily basis.
Hence
for these snakes, they have no handling stress or fear of human interaction
with them.
No
masturbated reptiles of any taxa ever attempted to flee or bite.
Masturbation
of non-venomoid dangerously venomous elapids is not something that should be
attempted, unless the handler is both experienced with the snake species, the
snake itself is relatively tame and the handler is happy to countenance the
possibility of a potentially fatal bite.
For
the record, masturbating the snakes did not yield any signs of stress on the
snakes.
The
only obvious variables in behavior noted were the obvious movements downwards
of the pelvic (or equivalent) region of the snake as they were stimulated, and
a greatly increased frequency of tongue flicker as the snakes were aroused.
Transfer
of semen to the female was via the pipette.
It
seems that not all snakes produce semen all the time.
In
our collection it became apparent that the snakes that mated most were those
that produced most semen. The
correlation was direct.
In
terms of the Tiger Snakes, for which we held 6 adult males as of end 2007, the
ones who mated the most all yielded copious amounts of semen readily, while I
was unable to get semen from some who rarely showed interest in sex.
Please
note that at the time this semen collection was done, the snakes were being
held on their own, as we were trying to avoid breeding this taxon as we have
trouble offloading the babies and hence for 2006/7 only one of four females was
actually mated (with their mating season also including summer of 2005/6, due
to our concern that these snakes store sperm for some time).
The
same pattern was yielded across other taxa of snakes (elapids and pythons) as
well as skinks, from whom we were able to get semen using the same method.
It should be noted however that lizards are far harder to stimulate than snakes due to their increased tail muscularity and other tissue present in the region that apparently makes direct hemipenal stimulation harder. (Please note the extreme care needed with tail shedding taxa to avoid any incidents of autotomy).
Notwithstanding
this, it was possible to extract semen from all lizard taxa we hold, which
includes Cunningham’s Skinks (Egernia cunninghami), Blotched Bluetongues
(Tiliqua nigrolutea), Eastern Bluetongues (Tiliqua scincoides)
and Shinglebacks (Trachydosaurus rugosus). Other lizards were able to be masturbated at other facilities to
yield semen to be used for insemination including smaller skink species, Lace
Monitors (Varanus varius), Gould’s Monitors (Varanus gouldi),
Bearded Dragons (P. barbata and P. vitticeps), Gippsland Water
Dragons and Robust Velvet Geckos (Oedura robusta).
Assuming the reptile (snake or lizard) is tractable, we found the best method to acquire semen was to simply hold the reptile in a way that is comfortable for it and to rub the hemipenal area (near the vent) with one finger with moderate speed.
You will know the reptile is stimulated as it pushes that region downwards, to give the angled position of vent region as seen as a snake attempts to copulate a female in the “natural” way. Most snake keepers are familiar with this positioning.
While
the male may evert a hemipene if stimulated, as a rule this does not occur, and
it is not necessary for semen extraction.
For reasons not completely certain, snakes (and lizards) will ejaculate
semen while the hemipenes remain retracted in the tail.
Hemipenal
plugs and dried feces may be shed and this should be disregarded (discarded).
On
some occasions, dried fecal matter may be around the cloacal region and this
should be cleaned away with a wet cloth before masturbating the snake so as to
ensure a “clean” semen sample is obtained.
As
a rule, if the snake has semen, it should yield it within 60 seconds. Cooler snakes take longer to yield semen
than warmer ones. The same applies for
lizards, albeit on a slower timeline, although smaller taxa yield semen faster.
As
a rule there is no need to check semen under a microscope for viability.
If
the snakes or lizards have been cooled over winter according to the regime we
use (see above), viable sperm seems to be a formality for almost all taxa, save
for the inevitable small percentage that will never be fertile.
As
part of the perfectionist system here, semen was checked under a microscope and
images sent to Dr Barrymore Walters, an expert whose day job involves human
vasectomy’s and microscopic inspection of semen samples.
While
snake semen is different to that of human, he seemed to think what I sent him
was OK and his judgment later proved correct.
Semen
from the semen plugs in snakes was checked and found to be clumped, which is
typical of dead and non-viable semen, indicating that snake semen does have a
limited “shelf life” although it is hard to ascertain what that is.
As
a rule, if a snake yields semen from one hemipenal pocket, it will yield from
both and I found that the best way to collect semen was to masturbate both
sides so the semen sat either just inside or just outside the ventral scale,
form where it can easily be sucked into a capillary tube. As a rule, one tube is used for each side,
enabling two lots to be gathered at a time.
Often
the hemipenal region is massaged to assist in bringing the semen towards the
vent for collection.
As
a rule, it takes 5-7 days for a snake that has yielded semen to be able to
regenerate semen again.
As
a rule, snakes do not yield semen in smaller amounts when an attempt is made to
extract semen in a period under the 5-7 regeneration period. Instead the snake yields nothing.
In
other words semen seems to be yielded in distinct “loads”.
The
semen that is viable and used is not the hardened material seen in dried
hemipenal semen plugs.
Instead
it is the milky white material that is obviously yielded at the time of
masturbation and as an obvious result of it.
To give an idea of the quantity, it is best to view a photo.
Sometimes
masturbation of a snake will yield a semen plug followed by good whitish
semen. In this situation the latter
(whitish) material, should be used only.
Interestingly
high sex drive snakes will still attempt to mount and mate females after being
taxed of semen.
This
is interesting because as a rule, once I have extracted a single load of semen
from each hemipene, I am unable to repeat the process until the 5-7 recharge
period has elapsed.
An
important question to ask, is whether or not a snake that mates immediately
after I’ve taxed it for semen is still able to pass viable semen (sperm) to a
female at that time.
Aviculturists
who do AI with birds said that they’d simply suck semen into the pipette and
then place it into the ventral opening of the bird and blow out the semen
inside the bird. They said in most
cases, the spermatozoa did the rest and conception was the rule.
The
same was done with the snakes, and we now know the same to be true for them as
well.
However
sometimes the semen was too viscous to be able to be blown out of the tube with
success. I then found myself trying to
blow out the semen without success and had to remove the tube from the
uninseminated snake.
Narrower
tubes were even harder to utilize than the originals and for the wider ones
other issues arose, mainly in terms of sucking up the semen and then being able
to blow it out, as opposed to just air.
You see unless the semen blocks the tube, it will give a pathway for air
to simply blow past it.
Due
to the nature of the human mouth, it was far easier to suck fluid into the tube
than blow it out. Hence the occasional
difficulty of blowing the semen out of the tube into the female snake.
So
the logistical problem had become how to quickly and effectively get the semen
into the female snake.
The
superior method developed was to get the male snake to the stage of yielding
semen. At that point the capillary tube
is placed in water to a point where a small amount of water is sucked in. This sometimes occurs automatically and
other times you may need to do this by careful sucking.
Water
is less viscous than semen and also known to be harmless to it.
Semen
is then sucked into the tube and then a small amount of extra water, making the
semen effectively inside the tube padded by water on either side.
By
carefully sucking either end of the tube, you will be able to move the semen
back and forth in the tube.
Once
you get to the stage where the semen is easily moved, you should attempt the
same by blowing.
Once
you get to the stage where you can move the semen up and down by blowing the
tube, and with relative ease, you are ready to inseminate the female.
The
cloacal opening is opened sufficiently to allow the tube to pass through.
Usually
this is simple, but if it is dry and tight, lubrication with water will solve
the problem.
In
summary the tube is inserted to a depth of just under about 3.8 cm in a 151 cm
long snake and the tube blown to leave the semen in the female.
You
will know that the semen is inside the snake when you notice the air back-up
(from you) going into the snake, at which point the tube is removed and the
vent held shut.
Assuming
this is done properly, the semen will remain in the snake and make it’s way to
the appropriate part of the female to fertilize ova or eggs.
In
terms of the insemination of the female, there are other important pointers and
notes. The tube will hit an apparent
(soft tissue) “block” when pushing in an anterior direction. To give an indication as to the approximate
depth of the “block” it should be about 3.8 cm into the snake if it’s a 151 cm
total length snake (18 cm tail and 133 cm snout vent). This should not be pushed or pressured and
the tube pulled back a few mm from this “block” point.
These
measurements as given here are important as they can be scaled pro-rata up or
down for larger or smaller snakes to give an indication as to likely and
expected penetration depths.
If
you find a “block” a substantially earlier than the indicated distance, then it
will be caused by fecal material ready to be expelled. This should be removed before attempting
insemination (see elsewhere in this paper for an explanation as to how this is
done) in a manner that is simple and painless for the snake.
Assuming
no fecal material in the relevant part of the snake then the insemination of
the snake should be routine and trouble free, and success for the procedure
assumed likely.
If
there is trouble getting the semen to be blown into the female, it is often
easier to blow and withdraw the tube at the same time. The backward movement creates a gap (void),
which then creates a vacuum to suck out the semen sample.
When
doing this, you may accidentally release semen either at the vent opening or
even outside the snake.
If
this happens, the semen (which usually presents as a sort of line of fluidy
gunk), can usually be sucked back into the tube and the whole insemination
process repeated.
Another
mishap that occurs occasionally is that you may suck in semen to your mouth and
then spit it out. Often this can be
reused as well.
While
none of this is sterile and there is an obvious germ transmission, no snakes
inseminated this way have ever shown signs of illness and noting that reptiles
cloacal openings are exposed to these germs in the normal course of crawling
over things, this is not seen as an issue worth worrying about.
If
the semen sample is degraded or lost before being implanted into the female,
then the second one obtained (usual), can be used.
Alternatively
if all runs to the theory and plan, it becomes possible to inseminate two
snakes from one snake on one day.
The
same as just described applies to lizards.
All
the above also assumes a pre-winter, winter, spring heating and cooling regime
sufficiently similar to ours so as to get both male and female fertility cycles
synchronized and viable.
How
long until fertilization takes place after copulation or insemination is hard
to ascertain and depends on variables such as “is the snake ready to breed?”,
potential sperm storage and ovulation cycles.
However
due to the fact my own breeding records have instances of snakes mating one day
and conception being measurable effectively from that date (no measurable
delay) and with no measurable differences in the development of young or eggs
when born (excluding incubation-based temperature variables for eggs), it is
reasonable to assume that active spermatozoa will travel to the correct parts
of the snake well within 24 hours.
The
significance of this known fact is when attempting to ascertain the likelihood
of the insemination of the female snake being successful in fertilizing
eggs/ova.
If
the snake defecates within 24 hours of insemination, then semen may be released
before it has time to work effectively.
As
a rule of thumb, if this occurs, it’d be logical to repeat the insemination
again, as soon as male semen becomes available (about a week if you only have
one viable male).
To
that end, it is possible to determine if a female snake is likely to defecate.
Females
can be palpitated and an impending defecation determined in terms of
likelihood.
While
the advice may be to delay insemination until after defecation, there are other
means to deal with this common potential problem.
In
the first instance semen should only be collected if the female is deemed
‘clean’, feces free and ready in every other way. If the female is likely to defecate, a delay may be in order.
Having
said this, in our situation the better method involved palpitating the female
for feces.
If
there was deemed a likelihood of defecation within a few days, the snake would
be placed in luke warm (25-30 Deg C water) in a sealed container (with air
holes only) to a depth sufficient to immerse the snake, but not too deep to
drown it.
Usually
such an environment will encourage any fecal material to be released within a
few hours of soaking.
After
this time the snake is placed back in it’s dry cage and after the snake and the
relevant part of the body has dried out, the insemination is done.
By
way of example, this regime was practiced with success when (successfully)
inseminating a Bredl’s Python, that was made to defecate before it was
inseminated.
The
same also applies to lizards, noting that for them it is harder to ascertain
major defecations.
It
has been suggested that soaking of snakes and lizards to encourage defecation
prior to insemination is advantageous in terms of maximizing success and if
there is not a ready supply of semen to use repeatedly (as in you only have one
chance of successful insemination), then soaking to ensure minimal risk of
fecal disruption is the best course of action.
Just
as snakes have no issue with sexing by “probing” if done properly and with
care, the same applies with insemination of female snakes if done with due
care.
Due
to the variable of minor defecations, that may also inadvertently release
semen, the advice for dealing with inseminated females is as follows.
The
cage it is kept in for the day or two following insemination should be small,
totally clean and one in which any new fecal material can be seen.
If
any defecation is seen within 48 hours of insemination, then my advice is to
re-attempt it on the basis that the first attempt may be a failure.
For
our set-up all snakes and lizards are kept in what are usually very clean
plastic tubs and because post insemination we ensure no fecal material is in
the cages/tubs, any defecations post insemination are easily seen.
Storing
semen and related issues
For
mammals and other taxa, semen is often stored frozen and often for long
periods.
Because
our method involved immediate or near immediate insemination, storage has been
a non-issue.
Sitting
in a room at room temperature, globules of semen will dry up quickly, being
noticeably drier and harder to deal with within minutes.
For
this reason, masturbation of snake and subsequent insemination should be as
quick a process as possible and as a rule can be executed within 60 seconds
from extraction to insemination, assuming everything is at the same venue.
Semen
in capillary tubes, takes a lot longer to dry out, due to the relatively small
amount of contact between air and semen.
Semen held at room temperature in a capillary tube, padded with water at
either end will last for hours and apparently not degrade if stored in a sealed
box, itself lined with moist tissue.
This
is known, because semen stored this way for several hours has been checked
under a microscope and found to be “normal”, enabling successful inseminations
to have been done in various collections across our home state of Victoria,
without the need to move reptiles.
This
method has already enabled successful inseminations to be done in numerous
reptiles in various collections involving reptiles that would otherwise either
never have copulated, or alternatively never have even been in physical
contact.
An
issue that has reared it’s head several times recently has been incorrectly
sexed reptiles.
At
our facility this has never been an issue.
All squamates are probed and this method (if done properly) remains the
easiest and simplest method to 100% reliably sex them.
Hence
in terms of breeding, insemination and the like, we’ve always been able to go
the males and tax them for semen, or impregnate known females.
Recently
we supplied semen to other keepers and have struck some interesting obstacles.
Semen
from a venomoid male Inland Taipan (Oxyuranus microlepidotus) was
useless when it became clear that the “female” that had supposedly been probed
as such was an obvious male. I saw the
2 metre snake with large tail and went through the motions of probing it as
male.
In
another incident, I used semen from one of my venomoid male Collett’s snake to
inseminate a long-term captive “female” that had apparently eaten a smaller
“male” some years earlier.
As
for the Inland Taipan incident, the person was a long-term herpetologist of
high repute, whom I had no reason to doubt.
I
took the semen from the male and implanted it into the “female”. This part was apparently routine. It was only after placing the “female” back
in the cage that I thought the tail of the “female” was too large. The snake was retrieved, probed and turned
out to be a male!
When
inseminating the (now known to be male) Collett’s snake, it was noticed that
the pipette didn’t hit the same “block” as seen in all the female snakes. In
other words it could be passed much further into the snake.
Hence
it emerged that sexing errors in males can actually be diagnosed at the
insemination stage as a second-best alternative to probing.
As
a result of this incident, measurements were taken on my three Collett’s Snakes
to give accurate indication as to where “blocks” seemed to occur when a pipette
was inserted through the vent.
These
were as follows:
Female: 151 cm total length, 18 cm tail, 133
snout-vent, 3.8 cm depth of pipette to “block” point.
Male (1): 169 cm total length, 20 cm tail, 149 cm
total length, 5 cm depth of pipette to “block” point.
Male (2): 152 cm total length, 18.5 cm tail, 133.5 cm
snout-vent, 5 cm depth of pipette to “block” point.
Similar
data came from taxa such as Red-bellied Black Snakes and Tiger Snakes, hence
giving a secondary means for sexing snakes and raising potential indicators of
sexing errors if the pipette passes further than expected before reaching a
“block”.
Mention
of these sexing errors is done here as it serves as a warning to budding
breeders who are not totally certain of the sexes of their reptiles.
It
may also be medically significant to the reptile if a sexing mistake is made.
Most
herpetologists are familiar with probing of snakes as described by Hoser
(1989).
The
probes are usually devices of varying sizes, that are metal rods with a ball at
the end. The sizes vary and the one
used is that which is of appropriate size that can fit comfortably into the
hemipenal pocket, with a ball at the end of sufficient size so as not to
“spike” the end of the hemipene if it actually travels that far.
In
terms of probing a snake, the operation is delicate and should be done with the
utmost care and precision as it is easy to injure the soft tissue of the
hemipenes, or corresponding tissue in females.
As
a rule, the probe should not be inserted the full depth of the hemipenal pocket
as it is rarely needed to accurately sex the squamate. I have seen many snakes probed by novices
that have sustained injuries (sometimes eventually fatal) from probes going
through one or other hemipene.
When
probing, once the probe has been inserted to a point where it is clear the
depth indicates the sex as male (say about 7 scales down for most snakes),
there is no need to push the probe further.
Due
to the fleshier tail in lizards, probing is often more difficult, due mainly to
difficulty in finding the position of hemipenal pockets, but the underlying
principals are the same as for snakes.
It
is perhaps unfortunate the probes are routinely sold to persons without
questions or training and who have no sensible training or experience in their
use. This no doubt leads to many
squamates being improperly probed by novices and potentially fatal injuries
arising (the usual cause of death being untreated infections from injuries to
soft tissue).
Worse
still are recent instances of so called “snakehandlers” claiming decades of experience,
which they do not have, doing so-called “courses” and teaching people, who then
go away thinking they know what to do, and who in fact have been taught wrong
or dangerous methods.
In
the last 4 decades, I have seen countless cases of this and in the age of
internet this problem has worsened.
Hence
it’s appropriate to issue a generic warning about probing.
IF
INEXPERIENCED, DO NOT PROBE A REPTILE.
DO
NOT ACCEPT TEACHING FROM A PERSON WHO DOES NOT HAVE INDEPENDENTLY VERIFIABLE
EXPERTISE.
DO
NOT BELIEVE A PERSON’S CLAIMS OF EXPERTISE UNLESS THEY ARE VERIFIABLE.
While
in theory, there is no shortage of capable and willing persons who will safely
probe reptiles, it may take a bit of time and effort to find a person to do
this at an acceptable time.
Most
veterinarians have no training in probing reptiles. Of the small percentage who can and do, some will charge a fee to
do so, but others will do it for free.
While
a “free” probing is likely if only a small number of reptiles are involved, the
situation may change for collections of dozens of reptiles. Note that the probing act usually only takes
a matter of seconds per reptile if the practitioner has experience.
A
number of (known to be experienced) private keepers and breeders will do
it. For them it must be at no cost, as
in most jurisdictions, including Victoria it’s illegal for a non-veterinarian
(not licensed as a veterinary surgeon) to charge any fee for any service that
can be defined as veterinary in nature.
However
the majority of capable persons are reluctant to take time out to probe for
persons they either don’t know, or have any compelling reason to do unpaid work
for.
In
other words, there is no short-term fix for the ongoing issue of unsexed or
improperly sexed (guessed?) reptiles in private care in Australia.
In
my own situation, I generally carry a set of probes in the car and also with
our reptiles when doing demonstrations and probe individual reptiles for
persons if and when requested and if and when it does not interrupt my own busy
schedule.
It
does not however solve the widespread issue of unsexed or improperly sexed
reptiles at facilities across Australia.
While
this paper has labeled the methods used as “artificial insemination”, the only
artificial stage of the process is in terms of the acquisition of semen and
then it’s implanting in the female.
An
alternative name for the process is therefore “assisted insemination”.
For
humans and other animals, Artificial insemination or “AI” sometimes refers to
the actual process of conception (sperm penetrating egg and fertilizing it) in
a non-natural environment such as a petri dish, as opposed to human movement of
semen.
In
terms of the methods described in this paper, it isn’t usually necessary to
view semen under a microscope.
As
already mentioned, if the reptiles have been subjected to a correct temperature
regime over the preceding year (in terms of inducing mating and breeding) and
there are no contra-indications, then it’s reasonable to assume that the males
carry viable semen and sperm.
If
intending to view semen under a microscope the recommendation is to retrieve
and view semen without any delay, so as to avoid drying of the sample.
A
day old sample or slide presents a very different view to a fresh sample.
Of
note has been the strong variation in shape and form of spermatozoa in given
taxa. The appearance of spermatozoa
also varies depending on the resolution of the microscope and the preparation
of the slide.
As
a rule, stained slides make the individual spermatozoa easier to see and
identify.
At
lower resolution (say around 100 X), the semen gives an appearance of being
striated in texture. The striations are
usually caused the tails of the individual spermatozoa. At higher resolution (say around 400 X), the
individual spermatozoa are delineated, including the head and tail. However due to the nature of a microscope’s
focusing, most spermatozoa will not be visible, with the resultant view being a
combination of heads and tails, with few if any complete spermatozoa being
visible.
Most
standard optical microscopes have resolutions of 100 X and 400 X.
In
terms of slide preparation, the general recommendation is to smear the subject
material very thinly over the slide, so as to yield a “single layer”, before
placing on the cover slip. Dilution in
water or dye (methyl blue), one droplet is more than enough, may assist for
several reasons, including delaying the inevitable drying of material under the
slide.
As
it happens, none of these methods are mandatory in terms of observing
semen. Semen is actually easy to place
on a microscope slide and also easy to view due it’s light coloured texture
(whitish to translucent).
If
the spermatozoa present as evenly distributed, it is reasonable to assume that
the sperm is viable.
If
they are clumped, they are likely to be unviable or dead. Such clumping is seen in slides from old and
dried hemipenal plugs often shed by snakes routinely and also shed prior to the
yielding of fresh semen at time of masturbation.
If
desired, and if only one snake (or lizard) is to be inseminated, it is
routinely possible to use one semen sample to inseminate the reptile, and if
this works according to plan, then use the other for microscopic analysis. This may give a better indication of likely
success of the insemination.
Photos
taken of microscopic material was done using a Pangor Microscope T-mount,
specifically designed to enable SLR cameras to take photos on a
microscope. The mounts are relatively
inexpensive (under $100) and available from specialist retailers and fit on all
major makes of camera, including in our cases, Pentax 35 mm SLR’s and Nikon
digital SLR’s. The mount I own only
fits over microscopes with relatively narrow eyepieces.
If
taking photos, a microscope with it’s own light source (as opposed to a mirror
to catch light) yields better photos.
Advantages
of AI over “natural conception” in the captive reptile situation.
Obviously
in cases where snakes won’t otherwise copulate, there is no contest in terms of
comparing the methods of conception.
In
terms of cases where a pair of snakes may naturally mate, use of AI has
questionable benefits and it is here that a judgment call needs to be made.
If
the mating is deemed likely, AI is redundant.
This happened with two out of three pairs of Eastern Brown Snakes. Two South Australian Eastern Brown Snakes (a
male and female) failed to mate and nothing I tried seemed to be able to induce
a mating. The female was therefore
inseminated and became gravid with fertile eggs.
Unlike
for previous years, in spring 2007, I was unable to get either of my male
Red-bellied Black Snakes to mate, so chose to use AI on the female.
Some
weeks after the AI, the three snakes were taken to the Tuggeranong Hyperdome
Shopping Mall in the ACT.
While
being held in a box together, the two males apparently attempted a “three-some”
as they tried to mount the female and one another. One of the males was removed and within minutes the other male
had “locked up” as in commenced copulating the female.
This
remained the case from 12 noon through the next on stage show at 1 PM, where
the snakes were held and demonstrated as mating to the audience of many
hundreds, and through the afternoon and into the night, at which stage the two
snakes remained in a box in a nearby motel room.
In
that case and with the benefit of hindsight, my early call to do AI on the
Red-bellied Black Snakes was probably unnecessary.
Because
it is routine to be able to tax a male snake for semen and successfully
impregnate the female within minutes, with no pain or suffering for any party,
AI becomes a compelling alternative for natural conception methods for a
sizeable proportion of captive reptiles.
At
our facility, for the 2006/7 season, most (but not all) breeding’s will be from
AI, and we have had to get a new incubator to deal with the expected rush of
eggs.
In
terms of masturbating snakes to extract semen, this method is also useful to
determine the likelihood of whether or not a given male snake will be inclined
to mate.
Consistent
failure to get semen (assuming you know how to properly masturbate the snake)
and assuming that the snake hasn’t recently mated or been taxed for semen, has
been shown to be a reliable indicator that the snake won’t mate or produce
offspring (at least in the short to medium term).
This
is a useful technique for potential reptile breeders with large collections of
given species, who may be considering which individual snakes (or lizards) to
cull from the collection.
At our facility it manifests as more gravid snakes than would otherwise be the case. Using the method described in this paper, over ten snakes of various taxa (elapids and pythons) as well as numerous lizards from all Australian families (excluding pygopodids) have been successfully inseminated and either produced fertile eggs or young, or are due to by early 2008. Most would not have bred otherwise.
For
the record, masturbating pygopodids for semen was trialed on a single male Delma
inornata with success, but the semen was discarded.
While
the first successful AI was done with venomoid Collett’s and Brown Snakes and
in it’s first wide application, venomoids of various taxa were the main
players, the method is probably usable for all squamates.
Because
it is so unbelievably simple and effective, there is no doubt that some people
will have doubts about the methods described here.
The
saying “it’s too good to be true” will be used.
“Why
hasn’t this been done on a wide scale sooner?”
Fuel
to this fire will be added by the usual band of critics who complain about
anything “Hoser”(see Hoser 2005a).
It
will be like the non-stop rants and false comments about the alleged death,
destruction, pain and suffering of the Hoser venomoids, the originals of which
are still thriving, mating and breeding four years after their venomoid
operations!
Again
see Hoser (2005a).
Done
judiciously and properly and in circumstances where reptiles may otherwise not
breed, AI as described here has no known or obvious downsides and yes, I’ve
been looking hard for any.
Having
said this, I have a band of critics, who habitually criticize anything “Hoser”,
and these inevitable criticisms are discussed here briefly and dismissed as
frivolous.
There
will be false claims on the internet of mass-wipe-outs of reptiles for the
purposes of alleged AI experiments.
Put
simply there has been no wipe out.
No
reptiles have died yet as a result!
There
will be claims of danger to the reptiles with AI.
If
you get a kitchen knife and slice off a snake’s hemipene’s it will probably
die. However in the real world of AI as
described here, this has not happened and cannot!
AI
in reptiles as first described here is in many ways like the venomoiding of
snakes as described first by Hoser (2004) and later papers. It simply has no downsides!
The
negative claims against the Hoser venomoids by the usual critics have long been
shown to be false. Just as venomoids
don’t roll over and die from a lack of venom, or from the relatively painless
operation, the same applies for artificially inseminated snakes. There is no mass mortality or downside.
However
in contrast to the venomoid operations, where the snakes do not regenerate venom
(contrary to false claims otherwise), the sole purpose of AI is to get snakes
to regenerate and reproduce themselves!
As
it happens, AI in elapids in particular is best suited to venomoids and so to
that extent, there is no doubt that this paper will get the hearts racing of my
strongest critics.
“Hoser
can Artificially inseminate Taipans and Death Adders and breed loads of them,
but no one else can!”
No
doubt there will be more claims of the “unfair competitive advantage” of the
Hoser venomoids.
However
there are a few claims that can (with humor) be truthfully made against myself.
“Raymond
Hoser is a wanker”.
Yes,
I masturbated some reptiles.
“Raymond
Hoser” sucks cum”.
Yes,
I have accidentally sucked snake semen into my mouth.
Hopefully
these two admissions will make all the critics happy.
There
is however one potential criticism of AI which has a sound basis of fact, even
if is not agreed with by a given person.
Because
AI enables transfer of semen from any reptile to any other, it makes the idea of
hybridizing taxa simple.
Formerly
unobtainable hybrids or rarer ones (as seen in some pythons, e.g. Female Water
Python (Katrinus fuscus) X Male Jungle Carpet (Morelia cheynei)
and Female Australian Scrub (Liasis amethistinus clarki) X Male jungle
Carpet (Morelia cheynei) as seen in Hoser 1988) can now be effectively
manufactured on call.
It
is the removal of pre-mating isolation mechanisms that allow this to be
possible and if there is opposition to hybridizing reptiles, this will most
certainly manifest in the form of opposition to AI.
Having
said this, Hoser (2005b) gave other previously unreported and unknown examples
of a breakdown of pre-mating isolation mechanisms without any form of AI
involving Death Adders, Copperheads and Tiger Snakes.
(Since
that paper was published, we have witnessed male Brown Snakes and Male
Copperheads try to mate one another, and also male Red-bellied Black Snakes
engage in combat with male Eastern Brown Snakes at Tuggeranong Hyperdome, ACT
in October 2007, immediately before the male Red-bellied Blacks were then
separated, placed with a female Red-bellied Black and then both were seen
trying to mount her in the above reported attempted “threesome”).
Hybrid
reptiles are generally regarded as worthless here in Australia and in terms of
pythons at least, they sell for less here than the “purebreds”.
In
the USA the picture is mixed, where some of the more unusual hybrids such as
“Carpondros” (Green Python (Chonropython viridis) crossed with Carpets (Morelia
variegata et. al.) sell for huge prices.
With
AI making these hybrids theoretically accessible to more people, it is likely
that after an initial rise and spike in the number of hybrids, the novelty will
wear off and AI’s main long term application will be simply for breeding rarer
and harder to breed taxa or for facilities such as ours where the keeper does
not hold large numbers of given taxa and has a greater dependence on single
individual reptiles for breeding success.
The
main features of AI as detailed here in it’s wider application will be even
more captive breeding of reptiles, a corresponding drop in retail prices for
private keepers and better still a direct reduction in pressure and
exploitation of, potentially limited wild stocks.
Reptiles
detailed in this paper were held and moved under various permits and acquired
from several sources. In all cases,
State Wildlife authorities issued permits and movement advices promptly when
asked and as always this is appreciated.
Individuals who supplied snakes and lizards referred to in
this paper, or held at the same time and inspected, but not referred to here
include the following: Scott Eipper, Adam Elliott, Paul Fisher, Robert Gleeson,
Ian Renton, Federico Rossignolli, Alex Stasweski, Drew Williams, Andrew Wilson,
Peter Whybrow and several others.
Several veterinary surgeons supplied equipment, advice and the like for the above reptiles, but as a result of
criminal threats made against one in relation to the Hoser venomoids in 2006,
their names are not published here.
End notes
All procedures described herein have been conducted with
veterinary supervision. All snakes
identified as “Hoser venomoids” as defined herein have been certified as such a
number times by a licenced practicing veterinarian as permanently devenomized a
number of times to satisfy demands of licencing authorities and other
government entities (including for example Worksafe Victoria) in more than one
Australian state.
To end October 2007, there have been at least 17 known
“bites” (as in two fangs at least once and full skin penetration, in all
cases), from the Hoser venomoids and in all cases, all were totally untreated
and in all cases there were no symptoms or effects on the person. These bites, involving a total of 8 separate
people, have included bites from adults of the following taxa, Inland Taipans,
2 snakes, 4 bites, Tiger Snakes, 4 snakes, 9 bites, Collett’s Snake, 1 bite,
Eastern Brown Snake, one bite, Common Death Adder (Acanthophis antarcticus), 1 bite, Dajarra Death
Adder (Acanthophis woolfi) 1 bite.
Since 1 July 2005, it has been illegal under Section 32 of
the “Occupational Health and Safety Act 2004” to display or demonstrate
venomous species of snakes in a public place in Victoria that has not had it’s
venom glands surgically removed.
Hoser, R. T.
1988. Hybridisation
between three different species of Australian Python. Litteratura Serpentium (Holland),
8(3), pp. 134-139.
Hoser, R. T.
1989. Australian Reptiles and Frogs.
Pierson Publishing, Mosman, NSW, 238 pp.
Hoser, R. T. 2004. Surgical Removal of Venom Glands
in Australian Elapids: The creation of Venomoids. The Herptile 29 (1):37-52.
Hoser, R. T. 2005a. Surgically
enhanced venomous snakes. Venom glands out, silicone implants in! The creation of perfect exhibition snakes in
the post HIH era. Crocodilian - Journal of the Victorian Association of Amateur
Herpetologists:17-28, 5(2)(August 2005):17-28 (and
covers),5(3)(November 2005):30-36.
Hoser, R. T. 2005b. Pecking orders in large venomous Snakes from South-east Australia …
ecological and distributional Implications. Boydii (Journal of the Herpetological Society of
Queensland), Spring: (33-38)
Hoser, R. T. 2006. Successful
keeping and breeding of Eastern Brown Snakes (Pseudonaja textilis)
including an assessment of previously documented failures and reasons
for them. Crocodilian -
Journal of the Victorian Association
of Amateur Herpetologists 6(2)
(August):16-28.
Hoser, R. T. 2007. Garbage Guts - Australian Tiger
Snakes. Reptiles (USA) (March),
15(3):48-60.
© Australia's Snake Man Raymond Hoser.
Snake Man®, Snakebusters®, and trading phrases including: Australia's BEST reptiles®, Hands on reptiles®, Hold the Animals®, and variants are registered trademarks owned by Snake Man Raymond Hoser, for which unauthorised use is not allowed. Snakebusters is independently rated Australia's BEST in the following areas of their reptile education business.