Dr Sleightholme and Cameron Campbell on thylacines

We have joined a great Thylacine group on facebook run by Wade Francis
The Thylacine Open Debate and Discussion Page
Dr Sleightholme and Cameron Campbell have responded to members questions..

We have our responses from Dr Sleightholme and Cameron Campbell.
Here is what we were sent.......
Both Cameron Campbell and I thank you for the invitation to participate in the Q&A session for your Facebook group. First, a little about our backgrounds:
Dr Stephen Sleightholme is author of several scientific papers on the thylacine and Project Director to the International Thylacine Specimen Database. Now into its 6th revision, the ITSD is the culmination of a major cooperative effort between museums and universities that hold specimens of the thylacine (Thylacinus cynocephalus), to produce the first comprehensive study of all that is known to physically remain of this unique species. In 2005, the ITSD was presented with a prestigious Whitley Award, the first time in the history of the awards that a citation had been presented for a database.
Cameron Campbell is Curator of the online Thylacine Museum and author of several scientific papers on the thylacine. The Thylacine Museum is a world class educational resource and the most comprehensive source of information on the thylacine available anywhere on the web, or for that matter, in any conventional museum display. Now into its 18th year, the museum was an early pioneer in internet education, being one of the first natural history websites. The latest revision brings together expert opinion from many disciplines, and this, combined with its many interactive features, ensures that the site appeals to both the amateur naturalist and academic alike.
1/Warren Darragh- Does the study of wet specimens and the fossil record support Bergman rule?
Stephen responds:
As far as I am aware, no research has been undertaken to support or reject Bergman’s rule with respect to the thylacine. Few thylacine specimens (wet or dry) note the place of capture, most only recording that they originated from Tasmania. Because of this omission in provenance, we are unable to state that thylacines caught in the colder highlands were larger than those caught in the warmer lowlands.
2/Branden Holmes- Is he going to publish the paper he was working on with Heinz Moeller about thylacine dentition before Moeller passed away?
Stephen responds:
At present, no further work has been undertaken on this paper, as other projects have taken precedence. That said, it is an area that Cameron and I may return to at some future date.
3/Warren Darragh- How evident is sexual dimorphism in thylacine?
Stephen responds:
Sexual dimorphism is evident in the thylacine, with adult males being around 14% larger than adult females. It should be noted that this figure is based on a limited study of 28 animals [18 male and 10 female]. In this sample, the mean male total body length from the nose to the tip of the tail was found to be 1.61m, and the mean female total body length 1.38m.
4/Nicole Dyble- Wonder if males would also have larger head and generally larger in size like other marsupial carnivores....but can be difficult to determine gender in juveniles.
Cameron responds:
With respect to the thylacine’s head, there is a marked difference in the skull size between the sexes, the male thylacine having a proportionately larger skull with a longer face. The skull of the female is distinguishable from that of the male by its smaller size, shorter muzzle, less expanded zygomata, and with respect to its dentition, smaller but proportionally larger teeth.
5/Branden Holmes- Any papers currently in the process of being written/accepted/published?
Stephen responds.
Cameron and I have three papers in production. A paper entitled “The International Thylacine Specimen Database (6th Revision - Project Summary & Final Report)” is currently in review for publication in the Australian Zoologist later this year. A second paper entitled “Stripe pattern variation in the coat of the Thylacine (Thylacinus cynocephalus)” is submission ready, and a third paper describing two previously unknown photographs of thylacines at the London Zoo is currently being written.
6/Warren Darragh- In various commercial productions on the thylacine there have been differing views on the animals maximum jaw gape. What would be your estimate be?
Cameron responds:
The gape angle is often quoted as being in the order of 120 degrees. This however, is a gross exaggeration, as opening the jaw more than 80 degrees would violate the integrity of the joint.
7/Louise Sherratt=Does he think they are still alive?
Cameron responds:
Stephen and I recently published a paper in the Australian Zoologist entitled “A retrospective assessment of 20th century thylacine populations”, in which we presented the first comprehensive study of the thylacine’s post-1900 range, based on the retrospective analysis of 1167 geo-referenced capture, kill, and confirmed sighting reports, from 1900 to 1940. In the paper, we examined the probable causes of population collapse, and discussed the possibility that the species survived into the 1940s and beyond. We concluded that the thylacine certainly survived beyond Benjamin’s (the last known captive thylacine) demise in 1936, and that the species was extant in the 1940s and probably beyond. As to its present-day survival, my answer would be possibly, as one cannot easily dismiss the Naarding sighting in 1982, or Col Bailey’s sighting in 1995, as misidentifications. Understandably, the scientific community demands a body or proof photograph / video to confirm the continued existence of the species, and to date, that has not been forthcoming.
8/Christine Mats- And if yes, does he think it's more likely to be on the mainland or Tasmania-New guinea?
Cameron responds:
I would think it far more likely that the thylacine survives in Tasmania than on the mainland. That said, one cannot discount all mainland sightings. The 1973 Doyle footage from South Australia and the 1984 Kevin Cameron photographs from Western Australia are rather interesting, and take some explaining if we dismiss them as being a thylacine. Much of New Guinea’s rugged interior remains unexplored to this day, and it is anybody’s guess as to whether the thylacine still survives on the island. Certainly, the thylacine was present there during the Pleistocene, as indicated by the discovery of fossil remains. Prior to about 1930, there were an estimated 1 million people living in New Guinea that were unknown to the outside world, so it is interesting to speculate on what as yet undiscovered species (including mammals) might possibly exist in the dense forests of the island’s mountainous, difficult to traverse interior.
9/Warren Darragh- How might a citizen scientist get access to the international thylacine database?
Stephen responds:
The sixth revision of the International Thylacine Specimen Database will be released online towards the end of 2017, and will be accessible through an academic portal on the Thylacine Museum website.
10/Steve Crawford-As a carnivorous marsupial, how was its locomotion in respect to its prey. Did they primarily use stamina or ambush as its main hunting strategy?
Cameron responds:
The thylacine is a pursuit predator and employs various hunting strategies dependent upon the nature of the prey being hunted, and whether it is hunting alone, or as a member of a larger family unit. This is discussed in detail on the Thylacine Museum website, at the links given below:
11/Mike Williams- How different was the locomotion of thylacines compared to canids..?
Cameron responds:
The thylacine is digitigrade, and like dogs and cats, walks on its toes. A major difference between the feet of the thylacine and those of a canid is that there is no webbing present between the thylacine’s toes. Thylacines also have proportionately longer rear limbs as compared to canids, giving them a rear-to-front sloping back, and a loping gait. Please see the following Thylacine Museum pages for further details:
12-Warren Darragh- As a follow up on the gait question- how does convergent evolution, combined with the need for predators to be efficient in their movement help explain (or not) post extinction sighting reports claiming thylacine have an awkward gait- when members of the canine do not?
Cameron responds:
I would prefer not to use the term “post extinction” in the context of sightings, as we do not yet know with certainty if the extinction event has occurred. The thylacine was / is perfectly adapted to the environment in which it hunted. It is a stealth predator, and as such, is not designed for long bursts of speed. Numerous historical reports mention that the thylacine has an unusual gait, often described as loping. Anatomically, this would not necessarily be inefficient in comparison to the gait of a canid.