In the 18th and 19th centuries, explorers in Tasmania brought back tales of a strange creature that looked like a wolf with tiger-like stripes on its haunches. That animal was the thylacine. It was a marsupial, one of several mammals that raise their young in pouches, and more closely related to kangaroos and koalas than to dogs or cats.
Nonetheless, the similarities stuck, and they earned the thylacine several nicknames including “marsupial wolf” and “Tasmanian tiger”. Superficially, the dog-like features are most obvious. Its species name – cynocephalus – literally means “dog head”. In fact, its skull looks so much like that of a dog that professors at Oxford University would ask students to classify it, as a trick question in their final exams.
But the rest of the body tells a different story. After studying the thylacine’s elbow joint, Borja Figueirido and Christine Janis from Brown University think that it ambushed its prey like a cat, rather than chasing it down like a dog. It was more Tasmanian tiger than marsupial wolf.
Sadly, no one knows very much about how the thylacine behaved because human settlers, as is their way, exterminated it before anyone could properly study it. The last wild thylacine was killed by a farmer in 1930, and the last captive animal died six years later. Thankfully, their bones are still around and they still have much to reveal. Most of the attention has focused on the skull, but Figueirido and Janis wanted to look at the elbow instead.
The elbows of dogs and cats are distinct from one another, thanks to their different hunting styles. Dogs wear down their prey over the course of lengthy chases, and their legs are adapted for speed and stamina. To achieve that, they have sacrificed mobility around their elbow joints. Cats are different; they are ambush hunters that rely on stealth and speed to take down their quarry. Their elbow joints are more flexible, allowing them to twist their forearms and wrists, and grapple with their prey. You can see this movement in action when lions swat at the legs of fleeing gazelles, or when house cats bat at a ball of yarn.
By comparing eight thylacine elbows with those of 31 other mammals, Figueirido and Janis found that the thylacines cluster with ambushers rather than pursuers. It might have the skull of a dog, but it has the elbow of a big cat.
The duo’s conclusion fits with the results of some previous studies. For example, by creating a virtual simulation of the thylacine skull, Stephen Wroe concluded that it specialised on small prey, unlike the larger targets of pack-hunting wolves.
This doesn’t necessarily mean that the thylacine grappled with its prey in the same way that cats do. Its structure might reflect the constraints of its past. Like all marsupials, thylacines were born as tiny, grub-like babies that needed to crawl into their mother’s pouch. Figueirido and Brown suggest that they might have needed flexible forearms to make the trip. In that case, it might have been impossible for marsupials to evolve into dog-like marathon hunters.
Reference: Figueirido & Janis. 2011. The predatory behaviour of the thylacine: Tasmanian tiger or marsupial wolf? Biology Letters http://dx.doi.org/10.1098/rsbl.2011.0364
May 3rd, 2011 at 9:05 pm
According to the picture showed in the article, also the animal seems to be plantigrade as bears and humans, instead of digitigrade as dogs and cats are. At least concerning its hind legs
May 3rd, 2011 at 11:18 pm
Watch the video! (Last captive thylacine.)
http://www.youtube.com/watch?v=6vqCCI1ZF7o&feature=player_embedded
May 4th, 2011 at 12:15 am
The elbows of dogs and cats are distinct from one another, thanks to their different hunting styles.
You know, I’ve often wondered why cheetahs look so dog-like. That helps explain it. Thanks!
May 4th, 2011 at 1:22 am
Hi Ed,
You correctly cited Christine Janis when you first mention her, but then later (in two places) you say “Figuerido and Brown” instead of “Figuerido and Janis” (from Brown University).
A side note… a question on the final in Christine Janis’ comparative biology class I took as an undergrad is still my favorite test question of all time: “It is said that Samson slayed a thousand Phillistines with a jawbone of an ass. Describe how you might use the jawbone of an ass as a weapon. Be descriptive as possible with respect to features of the bone”.
[Oops. Fixed. Thanks, and what an amazing question! - Ed]
May 4th, 2011 at 5:53 am
There seems to be a problem with the DOI link (at least for me).
Interesting article and research, but there is an issue in that the modern Carnivora have specialised into particular locomotor and hunting niches quite effectively in light of competition and a predator-prey arms race. This allows fairly clear categories of locomotor behaviour to be identified and linked to prey capture, due to niche segregation.
In the Thylacine there seems to be an assumption that the postcranial skeleton is similarly constrained, but if there were lower levels of competition between different marsupial carnivores there would be less niche segregation and less powerful selection for postcranial specialisation. What we may be seeing in the Thylacine is a more generalist body plan, with a suite of characters reflecting aspects of behaviour other than hunting (as you mention with the neonatal migration).
It would be interesting to consider the wrist, ankle, shoulder, pelvis and long bone ratios of the Thylacine using the same techniques to see whether these areas each tell a different story. If so we may need to approach reconstructions of behaviour of extinct taxa in a somewhat different and more holistic way. It may be that the postcrania of non-specialist carnivores provide relatively little information about hunting – except to say that a carnivore wasn’t a specialist.
May 4th, 2011 at 9:01 am
“The elbows of dogs and cats are distinct from one another, thanks to their different hunting styles.”
Or is it that their hunting styles developed in response to how they could better utilize the elbow joints (among other features) that they developed?
I sometimes get really confused when I hear people talk about evolutionary issues. The way this is worded implies, no it asserts, that because of a preference to hunt in a particular way, the elbow developed to accomodate that preference. Sounds very Lamarckian.
So seriously…which is it?
May 4th, 2011 at 10:30 am
@Roberto:
Ed Yong has used a kind of shorthand phrasing that can sometimes be confusing.
When he says,
“The elbows of dogs and cats are distinct from one another, thanks to their different hunting styles.”
the long form (and not as pretty a sentence) would be,
“Over time, those individuals who possessed more flexible elbows would find a greater survival value in hunting from ambush, while those individuals who possessed less flexible elbows would prosper with a long-run hunting style. Over thousands of generations, the descendants of these individuals diverged into cat and dog species, respectively.”
Mine is more scientifically accurate; Ed’s rings with the beauty of his usual pellucid prose style. You choose.
May 4th, 2011 at 10:59 am
Fascinating article. It made me feel ashamed though: another one of Dog’s incredible creatures eradicated through the hubris of Man. Makes me want to self-flagellate…and not the fun kind.
May 4th, 2011 at 1:57 pm
Bad English is breaching the levee, so I have to do this.
Infinitive, past tense, past participle:
–show, showed, shown
–slay, slew, slain
May 4th, 2011 at 2:06 pm
Great article. It is always tricky wtih the more ancient carnivores – cats having fewer genes than dogs, and having evolved from reptiles. Civets, hyenas and fossa being the odd ones; I read a study where veterinarians tried to guess the breed mixes of dogs just by sight and they got the answers wrong a majority of the time, which is why I think Linnaeus is so underrated.
Having said that, this guy reminds me of an aardwolf.
May 4th, 2011 at 3:01 pm
Artist Rachel Berwick has used the Thylacine as one of her subjects: http://www.rachelberwick.com/Hovering.php
She has also used as subjects the Coelacanth and “Martha” (the last Passenger Pigeon). Her artwork often focuses on extinction.
May 4th, 2011 at 5:13 pm
Jane, i think you mean “God’s incredible creatures” instead of “dog’s”
May 5th, 2011 at 2:44 am
Dear Alex,
No, I meant “Dog”.
May 5th, 2011 at 10:17 am
@Jim,
Thanks for the answer.
I believe your answer may be more scientifically correct. The problem does arise when people read and take what they have read at face value. I do not know Mr. Yong. I have no way of knowing if he is waxing poetic or speaking authoritatively as a scientist. When I make the assumption that he is purely scientific, his description of the hunting style leading to elbow development begins to support my Lamarckian thought processes and I get evolution wrong.
Does have a giraffe have a long neck because ancestors wanted to eat the tender leaves at the top? Or was it because only as tall trees developed, those giraffe ancestors with longer necks survived and passed on their long-neck genes? Or something like that? Was it force of will, or was it best suited for the task that survived?
If I read it as literature (fictional), I cannot take it seriously, I can only enjoy it. And it might POSSIBLY be thought-provoking.
My point is that wording can be very important. I happen to believe that we don’t need to fan the fires of those that just don’t ‘get’ evolution by wording things in ways we don’t actually mean. Cause and Effect are important links in the chain in the explanation of evolution. If we get C&E wrong in this thought process (if we did) why do we suppose we can get it right in the next thought process. Should we just trust that it will happen? What did he really mean?
May 5th, 2011 at 11:59 am
@Roberto,
Jim’s answer, as he explained, is more scientifically COMPLETE than the brief phrase used by Mr. Yong. Mr. Yong in no way confused cause and effect in his writing. He writes all day, everyday, about scientific and biological issues, and he assumes in his readers some basic level of understanding of biological mechanisms such as inheritance. Asking him to write every article as though it’s still necessary to refute Lamarck’s theories (or any other discredited theory of biology) is kind of pointless.
May 5th, 2011 at 2:33 pm
Another way that marsupial behavior has been investigated is by the ventilation constraints that come along with locomotion. At some point, non-marsupials lost two muscles that help improve the efficiency of breathing, but at the cost of enforcing a 1:1 breath to step ratio. This works acceptably for very long-distance locomotion, but is a serious restriction for sprinting, where much higher breath to step ratios happen.
http://www.mendeley.com/research/abdominal-muscle-function-in-ventilation-and-locomotion-in-new-world-opossums-and-basal-eutherians-breathing-and-running-with-and-without-epipubic-bones/
This by itself has major implications for prey capture strategies employed by marsupial predators. Have to say, I’m a little surprised the authors don’t address this; it would, from what I can tell, tend to support either the pure ambush perspective they suggest or an extreme distance pursuit, rather than any intermediate option.
Incidentally, it’s also probably why hopping is so popular among other marsupials.
May 9th, 2011 at 3:04 pm
So I guess we can now say that as long as one is an authority that one can transpose cause and effect to service a scientific journal because, after all, we all knew what he really meant.
The point has been missed, and I blame myself.
I am not confused by what he really meant. I do know, and know of, many people that would take the way it was written, run with it, expand upon it and … voila! …be expounding about how scientists cannot seem to make up their minds about how this evolution thing really works.
So, my point is this: when making scientific observations (as it is with any facts or data) , it is very important to word things properly. As a reader, it is not my responsibility to understand what the writer really meant. My responsibility is to read, understand and interpret. It is the writer’s responsibility to be clear.
May 9th, 2011 at 3:13 pm
This is true.
May 9th, 2011 at 6:51 pm
According to the picture showed in the article, also the animal seems to be plantigrade as bears and humans, instead of digitigrade as dogs and cats are. At least concerning its hind legs.
No, that was just a result of this particular specimen having received an injury to its left hind leg during capture. Healthy specimens were digitigrade, though they were also capable of assuming a “plantigrade-plus” stance by leaning backwards along much of their hindlimbs in a posture much like that of a kangaroo…. and yes, they could even hop on their hindlimbs like kangaroos, though they did so extremely rarely.
As for their hunting styles, there are ample reports from the 19th century of thylacines being extremely long-term endurance hunters, jogging relentlessly at distance behind their selected prey until it was no longer able to flee.
Probably the single best book ever written on the subject was “The Last Tasmanian Tiger” by Robert Paddle, and I highly encourage any interested readers to check it out.
http://www.amazon.com/Last-Tasmanian-Tiger-Extinction-Thylacine/dp/0521531543/ref=sr_1_1?s=books&ie=UTF8&qid=1304981454&sr=1-1
October 19th, 2011 at 11:31 am
Have there been any recent confirmed sightings? Is there any way to start up a search effort for these animals? Is there any way these animals can be bred in captivity to make the species dominant again? Please email a reply back to danceisasport@gmal.com ! Thank you so much!!!