Breaking the rules -
Male Tiger Snakes don't fight
Raymond Hoser
PO Box 599
Doncaster, Victoria, 3108
adder@smuggled.com
Phone:+61 3 98123322 or +61 412 777 211
Originally Published in The Herptile
31(1):27-32, (March 2006)
Abstract
This paper corrects a series of published reports to
the effect that Tiger Snakes (Notechis
scutatus) engage in male-male combat.
Reports in the literature are either mistaken cases of
males mounting males to try to mate them, or statements based on the assumption
that combat would occur due to males being the larger of the sexes and the fact
that male-male combat is common in other large elapids.
Tiger snakes are unusual in that while males are the
larger sex, both by average length and average weight/size, they don't engage
in male-male combat.
Other aspects of Tiger Snake behavior that have not
previously been reported are detailed in this paper.
Introduction
Tiger Snakes (genus Notechis) are a common species in populated parts of Australia,
including all major capital cities, except Darwin in the far north. A general precis of this species can be
found in general texts such as Ehmann (1992), Hoser (1989) or Worrell (1963).
They are well-known species in the largest cities of
Sydney and Melbourne and hence a lot of commonly observed behavior is not
necessarily reported on the basis that people assume it must be already
well-known.
The snakes are deadly venomous (see Hoser 1989). Hoser (1989) provides a photo of this
species mating and it seems to be no different to that seen in other Australian
elapids (see photos in Hoser 1989).
Male-male combat in Australian elapids had been known
for many years. For example a photo of
combat was published by Worrell (1963). Shine (1991) published photos of combat
in Eastern Brown Snakes (Pseudonaja
textilis), Taipans (Oxyuranus
scutellatus) and Lowlands Copperheads (Austrelaps
superbus).
Most Australian reptile books report on combat in
various Australian taxa, some providing photos. Some published papers in the scientific literature give examples
of and/or photos of combat in Australian elapids (e.g. Turner 1992).
It is widely written in the popular literature that
Tiger Snakes (Notechis scutatus)
engage in male-male combat, including for example Shine (1991), page 121 or
Ehmann (1992) page 424, which he then claimed as a first ever record of this.
Due to the frequency of the claim that Tiger Snakes
engage in male-male combat, it appears to have become an unquestioned truism.
Materials and Methods
At end 2003 and early 2004, I acquired ten Tiger
Snakes (Notechis scutatus) to use in
education displays. In line with their
species they were well settled in captivity, presenting no husbandry problems
note.
Their adjustment to captivity at my facility was
particularly rapid and complete due to the fact that they were never handled
with hooks, tongs, pinned, necked or tailed, all of which give snakes stress or
at best "tolerable" discomfort.
Instead they were humanely free-handled the same way as harmless
pythons, a situation enabled due to the fact they had their venom glands
removed in early 2004 (see Hoser 2004a, Hoser 2004b).
As an example of how well adjusted the snakes became,
by early 2005, the seven males would routinely mount any of the three females
to have sex, or likewise to other males if no females were present.
This activity included at public snake shows, where
snakes would mate as soon as being placed on a table in front of hundreds of
onlookers.
In other words, these shows were vastly different from
the prod and strike "this snake kills people" shows of other
"entertainers".
In other words the main basis of this study was the
observed mating behavior in the ten captive Tiger Snakes.
During the relevant period (end 2003 to early 2005), I
held a "controller's licence", which enabled me to remove and
relocate Tiger Snakes (and other reptiles) around Melbourne (e.g. 31 Tiger
Snakes in the year ending March 2004 and a similar number the following
year). This afforded me the opportunity
to observe these snakes in the wild, including mating and male-male
interactions at the times I had to remove the snakes from people's properties.
In the period September-December 2004, a limited
number snakes "in transit" between capture and release locations were
put with one or two of my own captive males in order to further observe mating
and/or combat. In terms of my males,
only two had been "cooled" the preceding winter and only these two
snakes were mixed with "in transit" snakes.
(Cooling at my facility meant 7 weeks of no warmer
than 20°C, followed by a regime of heat mat
on for 12 hours a day, then 12 hours off).
Both males mated any females they were put with.
Due to risk of disease transmissions (in any
direction), my own snakes and those in transit were only put in the same boxes
after they had been treated for exoparasites using aircraft spray (top of
descent - sprayed in box, then sealed shut for at least 60 minutes) and with no
water or other fluids in the cage. No
"in transit" snakes were held for more than about three days.
Results (The Hoser Snakes)
By the beginning of the spring season of 2004, all 10
Tiger snakes at my facility were large adults (1 metre or over).
In Spring 2004, most mating activity observed involved
the two males that had been "cooled" the previous winter. Those two snakes had been housed
individually (separated from all other snakes).
However mating activity observed increased among all
snakes, including those routinely housed in 2's or 3's, so that by late
February 2005, all snakes were engaging in mating activity including when
placed in boxes to be transported to snake shows or even at shows
themselves. I was doing reptile shows
most days.
Snakes were also moved about from cage to cage (at my
facility) so that all would meet one another.
The mating activity increased until about April,
whereupon it tapered off into May, after which all the males were isolated from
one another.
No combat was ever observed between any Tiger Snakes
at my facility, even when they were grouped in all combinations from 0-7 males
and/or 0-3 females. Certain male Tiger
Snakes (three out of seven) would try to mount other males if no females were
available. The mounted males would
either sit in the one place and allow the other male to continue, or it would
move away, only to be pursued by the other male who would continually attempt
to mate the male.
No sex-related or combat related behaviour was noted
between females.
As a rule, females approached by males would either
flee or raise and twist their tail to indicate a desire to be mated. At other times when both sexes had been
together for some time and no mating was occurring, females and males cohabited
without incident or evidence of sexual activity.
On some occasions I noted more than one snake trying
to mate another. As a rule, males were
housed in lots of 1, 2 or 3 snakes, although sometimes snakes were grouped in
larger numbers. On some of these
occasions I noted up to three snakes trying to mount one another (all males),
and once, I noted four snakes trying to mate one another (all males).
One male had a preference for his own sex, even if
female/s were in the same cage. That
snake would only mate a female if there were no other snakes in the cage.
No male Tiger Snakes showed any interest in mating
Death Adders, although during a shows, two Northern Hill Death Adders (Acanthophis bottomi) mated with female
Tiger Snakes and a female Lowlands Copperhead (Notechis scutatus). The A. bottomi were young at the time,
though adult, had never been cooled (that is their heating had been 24 hours a
day) and nothing came of the matings.
The two "cooled" males were in the spring of
2004 placed with male and female wild-caught Tiger Snakes and the results are
summarized thus. Females were mounted
and mated and generally released immediately after this. Copulation was usually effected within three
hours of the snakes being together (sometimes within minutes), and typically
lasted from 12-20 hours, although one mating ran at least 28 hours. Males appeared to display no sexual or
agonistic behavior towards one another.
This was expected on the basis that my two males used were not those who
routinely tried to mount other males and the wild-caught snakes in the same box
were probably not well-settled enough to engage in mating behaviour.
By contrast, wild caught females were effectively
"raped" by the males and hence had no choice in terms of the sex
observed.
Another result of note was at the Orbost Agricultural
Show on 14 March 2005.
A tangled mass of 15 venomoid snakes, including 9
Tiger Snakes, 3 Red-bellied Blacks (Pseudechis
porpyriacus), 1 Eastern Brown (Pseudonaja
textilis), 1 Lowlands Copperhead (Austrelaps
superbus) and one Death Adder (Acanthophis
antarcticus) were picked up from a table and placed into a plastic tub of
60 cm long. As per the routine, as soon
as possible (usually about 5 minutes later), the container is re-opened and the
snakes removed in lots of 2 or 3 to be placed in smaller containers for two
reasons. The first is to re-order the
snakes so that they are boxed in correct order for the next live snake show, in
terms of their being taken out and placed on the table. The second reason is so as to reduce
cleaning issues in the event of defecation by snakes by splitting up the
snakes.
In spite of the tangled mass of snakes, within minutes
the heaviest male (just under 150 cm total length) had connected (mating) with
the largest (over 120 cm total length) female.
They were left connected as I removed the other snakes, and remained
that way for the next few hours at the Orbost Show, as well as for the five
hour drive back to Melbourne and when placed back into a cage.
On other occasions, mating snakes (at my facility)
could be taken out of their box, placed on a rock for photographing and then
back into their box.
Some males keen to mate would stop feeding and not eat
food offered (5 of 7). Others would
feed when mating in that if food was offered when mating, they would take the
food, eat it and continue either mating (connected), or trying to mate if
unconnected (2 of 7).
Results (Wild Snakes)
Most Tiger Snakes caught under my
"controller's" licence were "singles", as in one snake
only. Hence they offer no insight in
terms of mating behavior.
However some removal jobs did involve more than one
snake. On one occasion (7 Feb 2003), I
removed a pair of male Tiger Snakes from under a slab of concrete at the side
of Diamond Creek Primary School. One
was mounting the other to try to mate it when found.
Tiger Snakes can be "tail sexed" with a
degree of reliability, but there are exceptions, making probing the only
reliable way to sex these snakes. Both
the above snakes tail sexed as males and due to my surprise to see what looked
like a male mating a male, I probed both snakes to confirm the provisional
diagnosis.
On 2 March 2005, I got a call from a Mr. Turos at 263
Elder Road, Greensborough, Victoria (a Melbourne suburb). He was in a state of panic observing three
large Tiger Snakes in his garden. One
went under a slab of concrete. It was
followed by a larger snake and that was followed by a third one. This was in a built up area, but the slab of
concrete was in an open patch of garden on a north-facing slope (important in a
cold town like Melbourne).
I went to the address 90 minutes after receiving the
call and used a crowbar to lift up the slab to catch the three snakes. Two were males and the third was female.
No combat had been observed.
Throughout the period 2003-5 I have received numerous
calls to remove Tiger Snakes from Blair Street, Warrandyte. The street is on the south bank of the
Yarra River (facing north) and due to the abundance of sheets of tin and
similar rubbish in the area is festooned with Tiger Snakes. No male-male combat has been observed
between snakes in the area, although mating has been.
Results (Other Herpetologists)
By early 2005, it was evident that there was no
male-male combat in my 7 male Tiger Snakes.
That the snakes lacked aggression towards me (or anyone else) indicated
their settled nature to captivity. The
snakes fed on anything offered, including fish (all kinds), crayfish, calamari
(squid), rodents, lumps of meat (all kinds), bones, and more than anything
chicken necks because of their availability and cheap price of $1 a kilo.
Noting that all mating and other activity was engaged
in with great vigor, it;d be fair to assume that male-male combat if typical of
the species would be seen among at least some of my snakes. Certainly in other collections, combat
between males of other taxa is common, including for example Panacedechis guttatus and Panacedechis colletti (see photos by
Hoser in Eipper 2002).
Calls were made to all other people I knew who either
kept or had kept numbers of Tiger Snakes.
None reported male-male combat.
Discussion
Why male Tiger Snakes don't routinely engage in male-male
combat is unknown. Reported cases in
the literature have not been corroborated by photos or video footage. This implies either that no such events have
been observed. Alternatively reports of
combat in Notechis are most likely
mistaken. Such could include:
Male chasing male to mount him.
Male observed mounting another male and confused with
combat.
Male biting male (as in a food bite) and bitten snake
either retaliating or thrashing, giving the appearance of combat in a sexual
sense.
Shine 1991 reports a very slight size differential in
favor of adult male Tiger Snakes (1 cm S-V greater). This measurement belies the much greater weight of most males
versus females. Furthermore, based on
what I have observed in Melbourne, it seems that the average male/female size
difference in favor of males is far greater than what is reported in Shine
1991, leading me to believe that he may have inadvertently included more
still-growing males in his sample than still-growing females.
Here I speak of non-growing adults as opposed to
growing but potentially sexually mature snakes, which seems to be the basis of
Shine's size comparisons.
Noting the general trend in snakes of combat being
general among species where males get larger than females, nothing in this paper
gives a reason for this apparent anomaly in Tiger Snakes.
However it is certainly something worth investigating.
Acknowledgements
Captive reptiles mentioned in this paper were supplied
by several individuals in several states over many years and under permits
issued by the relevant authorities. All
are thanked.
References
Ehmann, H.
1992. Encyclopedia of Australian Animals:
Reptiles. Angus and Robertson, Pymble, NSW, Australia:510 pp.
Eipper, S. C.
2002. Male combat in venomous snakes. Crocodilian
- Journal of the Victorian Association of Amateur Herpetologists
4(1):34-35.
Hoser, R. T.
1989. Australian Reptiles and Frogs.
Pierson and Co., Sydney, NSW, Australia. 238 pp.
Hoser, R. T.
2004a. Surgical Removal of Venom Glands in Australian Elapid Snakes: The
creation of venomoids. Herptile
29(1):36-52.
Hoser, R. T.
2004b. Silcone snakes cause sensation in Australia and elsewhere. Hard Evidence 4(6):25-29.
Shine, R. 1991.
Australian Snakes - A Natural History.
Reed Books, Sydney, NSW, Australia:223 pp.
Turner, G.
1992. Courtship behaviour and male combat in the Little Whip Snake Rhinoplocephalus flagellum (Elapidae). Herpetofauna 22 (1):14-21.
Worrell, E. R.
1963. Reptiles of Australia. Angus
and Robertson, Sydney, NSW: 207 pp.
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