Tuesday Tetrapod: Lophophorus impejanus

Posted by tigerhawkvok on January 27, 2010 00:09 in tuesday tetrapod

And for the second tetrapod this week, I introduce Lophophorus impejanus, or the Himalayan Monal:

L. impejanus

Male L. impejanus. Photo by Flickr user poplinre

The Himalayan Monal is a phasianid galliform (my phylogeny of birds is not well resolved in galloanserae [galliformes or anseriformes] — help out if you can!), with a number of the associated trappings (ground nesting, medium size, etc) of pheasants. L. impejanus weighs 1.5-2.5 kg, and is reasonably sized at ~67cm in length. It lives in open coniferous forests in the Himalayan region, 2100-4500 m in elevation.

L. impejanus

Female L. impejanus. Note the extreme dimorphism in color. Photo from the Wikimedia Commons.

The males are very evidently highly sexually dimorphic to females, having bright, iridescent feathers with a crest. Their median weight is also about 200g heavier than the females. L. impejanus is the national bird of Nepal, and as such, and due to its habitat, is not threatened. It is rated by the IUCN as least concern, having a large, stable, widespread population.

Tuesday Tetrapod: Hydrophis melanocephalus

Posted by tigerhawkvok on January 26, 2010 20:03 in tuesday tetrapod

Time for another double-post! Today's first Tuesday Tetrapod brings us an interesting group of snakes, a member of a group of elapids called the Hydrophiines — sea snakes. Today, we have Hydrophis melanocephalus, or the Slender-Necked Sea Snake

H. melanocephalus

H. melanocephalus. Photo CC-BY-NC-SA by Flickr user Nemo's Great Uncle.

H. melanocephalus

H. melanocephalus, swimming along the seabed. Note the lateral compression along the tail. Photo CC-BY-NC-SA by Flickr user Nemo's Great Uncle.

H. melanocephalus is one of approximately 70 species of elapids to have marine specializations. The bulk of the species are Hydrophiines, with Laticaudines being monogeneric (Laticauda). In Hydrophiinae, this manifests as salt glands around the tounge sheath for osmotic balance, full viviparity, almost nonexistent ventral scales, loss of 1-to-1 association with ventral scales:vertebrae, and enlongate neutral spines and haemopophyses for their tails.

Being fairly elusive, H. melanocephalus has not been evaluated by the IUCN. However, evaluations by other groups suggests it is highly venomous, endemic to the Indian Ocean region (South Chinese Sea, Vietnam, Japan (Ryukyu, Hokkaido, Kochi) Coasts of Taiwan and Guangdong northward to Zhejiang (China) Australia (North Territory?, West Australia), New Guinea Terra typica: Indian Ocean (type series from Indian Ocean and Madras, India) accoring to the catalogue of life). Sadly, the animal has been poorly researched.

Campaign Finance Again

Posted by tigerhawkvok on January 24, 2010 02:06 in politics

So, I thought more about the amendment thing, as an an exercise, I wote up a (I feel) pretty comprehensive amendment.

Article 1:
People and persons under the law, are defined as organic beings, autonomous in their healthy state, with DNA differing no more than 5% per chromosome, with respect to a mean genomic profile of 100 reference individuals, selected randomly from the population every 100 years, consisting of equal parts genetic male and genetic female.

Article 1.1:
This definition may be expanded by a 2/3 majority in the House and Senate to advanced organic beings recognized of personhood, or to artificially created digital intelligences.

Article 2:
Rights granted to organizations, unions, corporations, and other groups are only in scope explictly granted by Congress. New rights and priveledges granted to these groups will have a delay in implementation of no less than two years.

Article 3:
Organizations, unions, corporations, and other groups are prohibited from financing, advertising, or campaigning for or against any issues or candidates presented to the public for a state or federal election.

That, I think, covers all the bases — and is even forward looking!

NASA Temperature Data

Posted by tigerhawkvok on January 23, 2010 15:18 in misc science , public science

I got a comment on a tweet of mine from a friend of mine on Facebook:

Statistically? What does that mean? I mean, I think statistics like "1 in 5" or is that just NASA's way of saying '09 had an average temp equal to '98's average temp?

(Source: Facebook)

It's a pretty reasonable question, which kind of underlines the misperceptions on how temperature stuff is measured. John's second point is pretty close to the mark, but there are some subtleties that get lost along the way.

So, first consider the way these temperatures are measured. Obviously, there is inherent instrument error, but there are much larger sources of error. Consider what would happen if you had 100 sensors seperated by 1 m in Death Valley, one sensor in the middle of the Pacific, and one in Antarctica. Obviously, an arithmetic mean is grossly inadequate. So, the data has to be integrated in some weighted manner, which introduces statistical error. Then consider local effects. If you have a thermometer at location X, but if you move it one meter to the left a building drops a shadow over the thermometer. Which is "more true"? People and critters, etc, will experience both temperatures. Do you use both? What about locations that have such a situation, but only one sensor? You need a model to integrate the data.

Then consider what it means for the temps to be equal. Which is a higher temp: 30 +/ 0.3, or 29.8 + 0.5 / - 0.1 ? What about 30.1 +/- 0.7? There are good arguments on various sides, but the most honest thing to say is that they are statistically equivalent — that is, the temperatures all lie within the error bars of the other temperatures. However, the media would probably report the 29.8 temperature as the lowest and 30.1 temperature as the highest, though there is a compelling argument to be made for the reverse.

Here's a couple fairly extreme examples: is 32 +/- 0.1, or 30 +/- 5 larger? There is around a 30% chance that the second temperature is higher, and possibly as much as 3 degrees higher, which is significant. Statistically, you can't tell the difference between the two. A second case would be if you consider a stream of years with steadily improving detectors. If you had a five year span that the error bars kept shrinking, and each subsequent year was entirely within the error bars of the previous, can you say anything about trends in that data? Of course not.

Scientific data without error bars isn't scientific data, and it's a travesty the media almost never mentions error. There is a reason, though, that all the caveats are required and provided by people like NASA.

Questions for the Supreme Court

Posted by tigerhawkvok on January 22, 2010 18:03 in politics

I think this article very nicely summarizes my feelings on the USSC's decision yesterday (sans the partisan bit — I think that opposition to this *should* be bipartisan). Thus, I quote it in its entirety.

10 Questions About the Supreme Court Ruling on Campaign Finance

By Robert Schlesinger, Thomas Jefferson Street blog

Like many on the left side of the philosophical spectrum, I was taken aback at the Supreme Court's ruling this week in Citizens United v. FEC. Who knew that corporations were entitled to the same right to free speech that individual citizens are? I had heard phrases about corporate citizenship, of course, and being "good corporate citizens," but I had no idea that the five justices in the court's "precedent? We don't need no stinking precedent" bloc took it so literally.

But after further thought, I for one welcome our new corporate countrymen. I just have a few questions about which other rights and obligations of citizenship the court might want to grant corporations:

  • Do corporations have an individual right to bear arms? I mean other than Blackwater.
  • Will corporations now be counted in the Census for purposes of Congressional reapportionment and redistricting? If so, they're going to need a lot more seats for the Delaware delegation.
  • Do corporations have a right to vote? If so, must they have been in operation for at least 18 years? If so, sorry Google.
  • Must foreign-owned corporations get work visas before doing business in this country?
  • Do corporations have the right to an abortion? (Is that what happened to Conan O'Brien's TV show?)
  • Must corporations register for the Selective Service?
  • Are corporations led by same-sex-CEOs allowed to merge? Or is that only legal in Massachusetts, Vermont, New Hampshire, Connecticut, and Iowa?
  • At age 65, do corporations become eligible for Social Security and Medicare?
  • Would corporations be eligible for healthcare under the Obamacare plan? (Was the auto bailout the corporate equivalent of the public option?)
  • Finally: Are corporations now eligible for nomination to the Supreme Court?

In fairness I should note that all of these questions apply to unions as well. It's truly a brave new world into which these "conservative" jurists are leading us.

I am very, very bothered by this ruling, and time has not made me get less angry, only moreso. Corporations needing free speech and being censored is baloney. The employees can spend their money on political campaigns how they wish, and stockholders can do the same — with their own personal money. Giving this ability to the corporations themselves is just asking for a McDonald's president. Good job ignoring precedent, USSC; CFR was established by prior courts as OK in 1990, 1982, 1986, and 2003. *Sigh*.

Campaign Finance Reform

Posted by tigerhawkvok on January 22, 2010 11:21 in politics , news

So, the US Supreme Court (USSC, or Supreme Court of the United States, SCOTUS) yesterday overturned legislation dating back ~100, 60, and 15 years ago was overturned yesterday, allowing corporations and businesses to donate as much as they want to campaigns. Hello, Corporate America. First, I want to say this is not judicial activism, any more than Kitzmiller v. Dover was I want to say this is manifest judicial activism, as it overturns previous rulings by the USSC, as recently as 2003. However, given the current USSC makup, it is an inevitable decision. Now, since the Court overturned the legislative bits on the grounds that they were abridging the first amendment, we can figure out the crux of that past precedent by looking at what it says:

Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.

There are two ways to address this: either by defining terms, or by changing the reference point. I will consider the definition, first. Speech can be defined as using vocalisations to communicate. It is thus arguable that the entire first amendment applies to people, or persons. Since the campaign finance measures were struck down on unconstituationality, we need to look at amendments, an along this line here is a proposed amendment, based on the implicit and explicit use of people and persons as the objects to which the Constitution is referring:


People, and persons, under the law, are defined as organic beings, autonomous in their healthy state, with DNA differing no more than 5% per chromosome, with respect to a mean genomic profile of 100 reference individuals, selected randomly from the population every 100 years, consisting of equal parts genetic male and genetic female.

This explicitly excludes companies and corporations, requring rights to be enumerated to then rather than explicitly granted. Wording is chosen to prevent rare mutations (such as XXY) from disqualifying a person as a "person under the law", to smooth out individual genetic irregularities, and to accomodate population drift over time.

The difficulty in this method is, then, it requires ancillary legislation to grant groups basic rights. I don't think it's much of a problem, but in that case, we can look at a second class of amendments, ones affecting campaign finance only:

Amendment (v1; microdonations):

Campaign spending is limited to $100 donations per individual per campaign, adjusted for inflation to the 2009 USD, with an equal amount of public matching. A total limit to public matching may be declared by the states, but all individuals with at least 10,000 signatures are eligible for public matching.

Amendment (v2; gross transparency):

At the end of all video advertisements for a campaign or issue, a screen not shorter than 3 seconds and occupying at least 50% of the video frame used must list the name, dollar amount, fractional ad amount, and affiliation of the top five donors to that advertisement. Subsequent text must be listed revealing the location of a publicly accessible list with the full list of donors with the same information.

For nonvideo visual media, this notification must occupy at least 25% of available space. This information must be read out for audio media.

Amendment (v3; explicit opt-in):

Groups, corporations, and other agglomorations may not spend money on campaigns unless the money used are fully obtained by group members opting in to such spending with federal form XXX-NNNN. If a member or employee does not opt in, all money and profits derived from them is not allowed to be spent in this fashion. If the profits associated with this individual are part of a composite product, their fractional work in completing said product is the fraction of profit derived from such product banned from spending.

So, each of these has their ups and downs. The first just largely scales back campaigns, and puts every person an a thoroughly equal footing. Then, corporate rights are not abridged in that campaign financing has special rules that limit donations to people, an furthermore, no person has more buying power in an election than any other. Public matching is there to help the campaigners, and low signature count allows more viable, third-party candidates.

The second is pretty obvious. By being grossly transparent, buying out an ad is much less effective if the ad has the top five donors all from AIG.

The third would be the hardest to impelement, but keeps people honest. No double spending, and no working to influence a campaign in a direction you don't like. Corporations are free to spend as much as they like, but not on the back of employees who disagree with the policies they promote. Otherwise, in the status quo, it's possible for a corporationto directly oppose something you support, and for your donation to be meaningful, you need to donate X to override what your employer spent on your behalf, then pay Y, your own donation.

In any case, I think all of these would address the issue at hand, and all in a more-or-less fair way. Of course, another funny way to look at it would be to say since corporations are persons, bankruptcy is killing a company, which is thus murder. Which is a kind of amusing idea, and just as ludicrous as giving corporations full first amendment rights.


Edit: Reflecting, on the first proposed amendment, it would also have to state that legislation granting non-person entities person-rights have a delay of at least two years. This would allow people to elect-out representatives that allot too much power to corporations again, and not have such rulings take instant effect and nullify the point of the amendment. There are also AI concerns, but then the only way to include them from here is an intelligence threshold, which excludes certain people from the legal definition of person.

Archosaur Lungs

Posted by tigerhawkvok on January 20, 2010 12:45 in dinosaurs , evolution , biology , herpetology

Just a quick update, before I head to Indiana to visit Purdue and my friend Jessica. I realize I missed yesterday's tetrapod, but I prefer to postpone a week and post a better update rather than a very breif post every week (look forward to sea snakes next week).

In this week's science, there is a paper describing unidirectional airflow in alligator lungs, strongly suggesting that this formerly "avian-style lung" is in fact an archosaurian synapomorphy. That is to say, this paper gets as close as a single paper can get to outright saying that this is a mechanism that helped nonavian dinosaurs get so large. Archosaurs just keep being awesome.

On somewhat related news, I think I'll try to put up a few evolutionary YouTube videos. Rather than a pure bash-on-creationist style, though, it'll be focused on describing particular evolutionary lineages and evidence. We'll see how that works out, though I need to become much more familiar with movie editing software.

Embed HTML5 Video Seamlessly

Posted by tigerhawkvok on January 18, 2010 23:02 in programming , internet

Designing for some sites this weekend, I finished up a PHP wrapper that enables HTML5 <video> playback seamlessly on sites. The whole process is broken into very few steps:

One-Time Steps

  • Download LongTailVideo's JW Player, extract it, and put player.swf into a directory named "modular".
  • Into the same directory, save this fallback, explanatory image.
  • Create a folder named "videos".
  • Place the following code in an included PHP file, or somewhere else in your PHP document:
function embedVideo($file, $width=NULL,$height=NULL,$title=NULL,$poster=NULL,$force_mime=NULL)
  // code based on http://camendesign.com/code/video_for_everybody
  // encode video used by this as Ogg and h.264 / mp4
  // Make sure the $file provided is the FULL URL to the files, with no extension
  if($width==NULL) $width=640;
  if($width==NULL) $height=360;
  if($poster!=NULL) {
    $flashposter = "&image=$poster";
    $poster = "poster='" . $poster . "'";
  else $flashposter="";
  $objheight = $height + 15;
  $swfheight = $height + 20;
echo "<div class='video'>
       <video width='$width' height='$height' $poster controls='controls'>";
if ($force_mime) {
  //Mimetype fix for certain server configurations
  $location[$len-1]="?name=" . $location[$len-1];
echo "
	<source src='$file.ogv' type='video/ogg' />"; 
if ($force_mime) $file=$fileold;
echo "
	<source src='$file.mp4' type='video/mp4' /><!--[if gt IE 6]>
	<object width='$height' height='$objheight' classid='clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B'><!
	[endif]--><!--[if !IE]><!-->
	<object width='$width' height='$objheight' type='video/quicktime' data='$file.mp4'>
	<param name='src' value='$file.mp4' />
	<param name='showlogo' value='false' />
	<object width='$width' height='$swfheight' type='application/x-shockwave-flash'
		data='modular/player.swf?file=$file.mp4" . $flashposter . "'>
		<param name='movie' value='modular/player.swf?file=$file.mp4" . $flashposter . "' />
		<img src='modular/no_vid.png' width='$width' height='$height' alt='$title'
		     title='No video playback capabilities, please download the video below' />
	</object><!--[if gt IE 6]><!--></object><!--<![endif]-->
       <p>Download Video: <a href='$file.mp4'>'MP4' (h.264)</a> | <a href='$file.ogv'>'OGG' (theora)</a></p>

Now, go into the "videos" folder. Create a file named ".htaccess" and add the following:

AddType video/ogg .ogv
AddType application/ogg .ogg

That will work on many server configurations, but not all. In case your server is stupid (ie, will not honor the .htaccess file), also create a file "index.php" and insert the following:

$video = basename($_GET['name']);
if (file_exists($video)) {
  $fp = fopen($video, 'rb');
  header('Access-Control-Allow-Origin: *');
  header('Content-Type: video/ogg');
  header('Content-Length: ' . filesize($video));
} else {
  echo "404 - video not found";

OK, your server-side stuff is done. You only need to do all that stuff once.

Each Time

Now, you can make your video. Make your video however you want, but when you're done, head over to firefogg.org in Firefox 3.5+ and convert your video. Essentially any settings available there will work (as the point of the extension is to leave it playable in a browser). You can use other programs, but this one is more-or-less foolproof. Then, use Handbrake to convert your video into H.264. Make sure your video is saved as *.mp4, and has the same name as the *.ogv file. You should now have two versions of your video. Dump both of them in your videos folder.

Now, embedding your video? It's easy. Just stick in the following code when you want to spit out your video:


The first argument is a string with a path to your encoded videos. Don't include the file extension; the code takes care of that. All subsequent values are optional. The first one is video width, second video height, third video title, fourth a thumbnail for the video (I use the method suggested by the Theora Cookbook), if you made one. The final value only does anything if it's TRUE. Stick in "TRUE" if the video isn't playing in FireFox, and it'll feed the video through the index.php in your video's directory and it'll work automagically.

The code is XHTML5 compliant, and has no rendering errors when submitted to the browser with the XML mimetype. I've tested it in IE6, IE8, Chrome 4, Firefox 3.6, Opera 10.5, and Safari 3 for Windows.

Enjoy! I need to update LifeType to get it working on the blog, but you can see the code in action on one of Velociraptor Systems's sample pages. This code is free to use, and released under Creative Commons/GNU Lesser General Public License 2.1.. Let me know if there are any problems implementing it!

Tuesday Tetrapod: Acerodon jubatus

Posted by tigerhawkvok on January 12, 2010 19:33 in tuesday tetrapod

Bringing the TT's up to date, for the second Tuesday Tetrapod we look at the largest group of mammals on the planet, as represented by Acerodon jubatus, or the Giant Golden-crowned Flying-fox.

A. jubatus

A. jubatus. Image from the Wikimedia commons.

They are part of the only (probably highly paraphyletic) family pteropodidae in so-called "megachiroptera". The common name of the animal is obvious, coming from the long snout and pointed ears highly reminiscent of the red fox. Their diet is primarily composed of figs and other fruits, and act as an important pollinator in the Phillipines.

A. jubatus is the largest known bat, with an average wingspan of 1.5 m and weighing up to 1.2 kg. They are rated by the IUCN as endangered, with a 50% population decline in the past 30 years. The total population is estimated at 10,000 individuals, with the primary threat coming from a 90% reduction of the Phillipine old-growth forest.

As an interesting note, the image from the Wikimedia commons is the only free image available for this species.

Tuesday Tetrapod: Crocodylus niloticus

Posted by tigerhawkvok on January 12, 2010 19:09 in tuesday tetrapod

After a very full past few weeks, finally I return for a pair of Tuesday Tetrapod updates. In light of my sister's trip to Egypt, the first tetrapod this week is Crocodylus niloticus, or the Nile Crocodile.

C. niloticus

C. niloticus. CC-BY-NC by Arno & Louise.

Looking way back at the post on G. gangeticus, there wasn't much specifics back then on the relationships or on the biology of the animals. Well, C. niloticus is a crocodylid, being more closely related to gavialidae than to alligatoridae. Like all extant crocodylomorphs, hatchling sex is TSD (temperature-dependant sex determination). Morphologically, they have a number of adaptations to their aquatic lifestyle, including a well-developed secondary palat with choanae that open behind the secondary palate that can be closed off to facilitate underwater feeding. They also have a "shunt" system that can change their four-chambered heart to functionally three-chambered for increased oxygen saving and submersion time (Franklin & Axelsson 1994 | summary).

C. niloticus is widespread throughout central Africa, and capable of growing to more than 5 meters in length. Additionally, C. niloticus has the strongest measured bite force of any extant animal, reaching 22 kN. In addition to more common fare, they have been observed feeding on giraffes, lions, leopards, and rhinoceroses. As of 1996, they are rated IUCN least concern.

International Year of Biodiversity

Posted by tigerhawkvok on January 01, 2010 15:34 in General , biology , news , misc science , public science

2010 is the International Year of Biodiversity according to the UN — the IUCN will highlight a different endangered animal each day of the year, apparently. Today's animal is apparently the polar bear (remember last week's Tuesday Tetrapod? Ursus maritimus), but I can't find the list yet. I'll update this post when I do, but it looks like events and press releases and such will kick off on the 11th of January.

Paralysis of Choice

Posted by tigerhawkvok on January 01, 2010 14:46 in General , misc science , public science

I've had some down time, but not posting, what gives?

Well, it's not to say I've not had work — but the fact of the matter is it's difficult to work without my primary sets of files an such. So, while I can work, it is almost certainly more efficient to wait until I end my visit with the family tomorrow and return to San Diego. But this merely adds reasons as to why I should be posting, but haven't.

I give you the paradox, or paralysis, of choice. I have so many ideas knocking around in my head that I can't decide which to commit to ... keyboard? So, instead, Twitter has been getting some degree of linkspam and random commentary. But, topical subjects wait for no man. As is virtually a requirement, therefore, I give you ten significant events of the past decade in science. Farewell, naughts! Into the 10's!

  1. Kitzmiller v. Dover smashes ID into a fine powder. Creationists continue to ignore it.
  2. China proves to be a veritable treasure trove of non-avian dinosaurs, providing many, many feathered theropods that changes the way dinosaurs are drawn.
  3. The Large Hadron Collider is finished, then breaks. Some physicists propose the Higgs boson is working backwards in time to keep it from working. It is fixed, and is currently ramping up in power.
  4. An Inconvenient Truth brings climate change into the mainstream conciousness. Cue debate from both sides here (but regardless of your position, it *was* significant).
  5. Stolen emails from HadCRU contribute to the derailing of the Copenhagen talks, despite demonstrations the mainstream interpretations were false.
  6. The chytrid fungus (Batrachochytrium dendrobatidis, or B.d) steps up its affects across amphibian populations.
  7. The Spirit and Opportunity rovers begin their 90 day missions. They are currently on day 2189 and 2168 of their missions, respectivley.
  8. Photons from SGR 1806-20, 50,000 lyr away, hit us and fried some sattelites.
  9. Persistant antivax movements lead to an outbreak of mumps in Brooklyn.
  10. NIF was completed, with ignition tests due to begin this year.
  11. Obviously this isn't a complete list. Any other interesting bits of science I missed?

    And Happy New Year, everyone!

Tuesday Tetrapod: Zalophus californianus

Posted by tigerhawkvok on December 30, 2009 01:58 in tuesday tetrapod

While I suppose my Tuesday Tetrapods should be 12:7:5:1 Aves:Non-avian sauropsids:lissamphibia:theria, where's the fun in that? For the forseeable future, I'll just run with percieved inequities.

Working to reduce one of those inequities, time to address ecosystems! We've painfully neglected the tetrapod return to water, so let's take a look today at Zalophus californianus, or the California Sea Lion:

Z. californianus

Z. californianus. Image hotlinked to Wikipedia until after 1/2/10.

Sea lions, including Z. californianus, are part of the otariid node (and thus are "eared seals"). Like other pinnipeds, they have finned feet that are highly modified for swimming, with earliest fossils from their lineage originating about 23 million years ago with Puijila darwini.

In particular, Z. californianus is commonly used with humans for entertainment and utilitarian purposes. They are the most common "seals" used in shows (rather than true seals, phocids), and are trained by the navy to retrieve enemy divers. They are rated IUCN Least Concern.

Tuesday Tetrapod: Ursus maritimus

Posted by tigerhawkvok on December 22, 2009 14:36 in tuesday tetrapod

With Christmas just around the corner, it seems now is an appropriate time to put up a Tuesday Tetrapod post on one of the "north pole's" signature animals: Ursus maritimus, or the polar bear.

U. maritimus

U. maritimus. Photo CC-BY-NC-ND by Flickr user J.G. in S.F.

U. maritimus is the largest extant land carnivore, and the largest ursid. It is closely related to the brown/grizzly bears, but with a suite of adaptations which optimize its seagoing lifestyle and the cold climate. They are in fact close enough to grizzly bears (Ursus arctos horribilis) that the so-called "Pizzly Bear" has been found both in the wild and captivity.

Despite these genetic similarities, U. maritimus is phenotypically, metabolically, and behaviourally different enough to be classified as a distinct species.

The polar bear is currently rated as "threatened" by the Department of the Interior, a designation that caused a significant amount of political difficulties in 2008 when the IUCN determined that global warming was the primary threat to the species. Due to their habitat, they are difficult to track, though breakup of ice sheets and overal arctic warming has driven polar bear populations further south, interacting more with humans, thus causing an appearance of a population increase. Ursus maritimus is rated IUCN "vulnerable", with an estimated population reduction of >30% by 2050, up to 50%; with complete extirpation within 100 years due to climate change.

Tuesday Tetrapod: Macropus rufus

Posted by tigerhawkvok on December 22, 2009 14:14 in tuesday tetrapod

About time! Another Tuesday Tetrapod. We've been shirking mammals (though they do have the distinct minority of tet diversity), and have a nasty bias toward eutherians, so here's Macropus rufus, or the Red Kangaroo:

M. rufus

M.rufus. Photo CC-BY-NC-ND by Flickr user wallyg.

Macropus rufus is the largest extant metatherian, and a member of macropodidae, or "large feet". They are diagnostic as diprotodonts by the two large incisors on their mandible, and the characteristic syndactyl morphology of their feet. As with most metatherians, M. rufus is capable of reproductive diapause, where in this context they can delay the birth of any new babies until the current joey has left the pouch.

Red kangaroos can be quite large, with large males running up to 2m in height and 90kg in weight. The unique tendon structure in their feet means that the hopping method of locomotion is highly efficient, recovering most of their energy with each bound. This enables them to comfortably hop at 25kph, with bursts of up to 70kph.

M. rufus is rated IUCN "Least Concern" as of 2008 with a stable population.

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