PO Box 599
Doncaster, Victoria, 3108
Phone:+61 3 98123322 or +61 412 777 211
Originally Published in The Herptile 31(1):27-32, (March 2006)
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.
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.
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.
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.
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.
© 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.