Thursday, 23 January 2014

Kings of the New World (1): The Jaguar

by Rob Cooper

In the late 1700’s French naturalist George Louis Leclerc, Comte de Buffon (who is a strong contender for the ‘most unnecessarily long French name ever’ award) theorised that all life in the new world was innately inferior to that of the old world due to its poorer climate. In this series of articles I look to refute Buffon, who was otherwise a most admirable scientist and philosopher, and expose the majesty of American wildlife. It is worth remembering that Buffon later withdrew these claims after Thomas Jefferson presented him with a stuffed Moose. 

I begin with a trio of top predators vying for control of the southern American rainforests and wetlands. The first of our contenders is the eponymous ‘beast that kills in one leap’… The Jaguar

The Jaguar is the third largest cat on the planet, averaging 100kg in the Pantanal region of Brazil, and is one of the most unusual of the big cats. Superficially it resembles a leopard although closer inspection will inform you the Jaguar is quite a different beast. Similar to the tiger it is consummately at home in the water and predates on many aquatic and semi-aquatic animals. Unlike the leopard the Jaguar is covered in rosettes rather than spots and as evidenced by its stocky build and heavy limb musculature is a much more heavily built animal. A Jaguar has been known to drag a 360kg Bull over 8 meters in its jaws. The Jaguar also has the highest bite force of any cat and the second highest bite force of all carnivorous mammals able to apply a bite with nearly a tonne of force (916kg).

The Jaguar is commonly mistaken for a ‘black panther’ a term that generally encompasses darker coloured Jaguar and Leopards. In reality there is no such thing as a panther and the black colouration is the result of a genetic mutation causing overproduction of the pigment making the coat appear black. However upon close inspection it is clear the usual coat markings are present. Similar mutations can be found in almost all extant animal groups.

But the main way in which the Jaguar differs is in its prey base and method of killing. The Jaguar is a great generalist and hunts a huge number of reptile species from Caimans to turtles and even the fabled anaconda and is capable of hunting all terrestrial and aquatic  vertebrates that share it’s habitat including tapir, sloths, capybara, deer, peccaries, armadillos, fish and all manner of monkey species.

Whilst the Jaguar often kills its prey via placing its jaws around the throat and suffocating the prey as many modern big cats do it is also uniquely proficient at biting straight into the skull of prey items; a technique rarely seen in mammalian predators . This appears to explain why the Jaguar has such an enormous bite force. In prehistoric America this killing technique allowed the Jaguar a crucial advantage over sabre toothed cats who tended to slash the aorta and trachea of their prey. A group of large mammals at the time known as glyptodonts (related to the modern armadillo and could reach the size of a small car) had their neck obscured by a large protective shell, rendering the attacks of sabre toothed cats huge canines moot. However this defence was ineffectual against the Jaguar which could bite straight through the skull of the giant glyptodont and secure itself a meal unavailable to its more specialised contemporaries. 

Even today the Jaguar still exhibits a remarkable affinity for hunting creatures normally off the menu to most mammalian predators and as this remarkable video shows is capable of stalking and killing the semi-aquatic Caiman from the Caiman’s preferred environment… The water and acutely shows why the Jaguar is often described as a beast that can kill on one leap.

The Jaguar is currently a near threatened species. Rapidly declining populations across South America mean it is likely to face extinction in the near future. The reasons for this are roughly two-fold; deforestation and persecution by farmers and livestock owners. In comparison to most cats attacks on humans perpetrated by the Jaguar are exceedingly rare but the taking of livestock is common. This has led to the cats being shot on sight and even the origin of professional Jaguar hunters, paid by farmers to kill local Jaguar.

This threat however is more than a threat merely to Jaguar. As the top of the food chain in many areas of South America the Jaguar represents a Keystone Species meaning it plays an important role stabilizing ecosystems by maintaining population numbers. This means the decline of the Jaguar could well lead to the decline of many new world ecosystems. However this also means that the protection of the Jaguar can safeguard a wide range of organisms and ecosystems. The Jaguar is also a principal Umbrella species; a species that has a range sufficiently broad that, if protected, ensures the protection of many smaller ranging species. 

As well as being a majestic and powerful creature the Jaguar offers a medium by which a large portion of new world flora and fauna can be safeguarded by protecting only a single species, making the mighty big cat even more relevant today than it ever has been before. 

Check out this awesome video of a jaguar taking down a crocodile!

Sunday, 19 January 2014

Art of Science

The 'Art of Science' is an annual competition that the Faculty of Medical and Veterinary Sciences at the University of Bristol hold. Researchers in the Faculty submit the coolest of images to be judged this year by our very own Dean, George Banting and Sabrina Taner from Wellcome Images.

Check out some of the images from the competition held in December that are on display in the @Bristol Cafe.

Rachel Curnock

Laura Senior

Ilona Aylott

Nicole Antonio

Sasha Woods

Saturday, 11 January 2014

China Lead World in Push for Wind Power

by Toby Benham

China plans to more than double its number of wind turbines in the next 6 years. This bold move involves increasing the nationwide wind power capacity from 75 gigawatts (GW) to 200 GW. To put this into context, all of the countries of the EU combined have a total capacity of around 90 GW. This is an important positive move for a country that is a leading contributor of greenhouse gases. Wind turbine technology is improving due to the massive market potential. Current efforts are innovating the field while simultaneously lowering prices. This is beneficial to other countries worldwide. The opportunity arises to either purchase turbines from the Chinese or further their research. While sustainable energy is the way forward there are still problems to be addressed. 

While China contributes to 26.7% of the worlds installed wind power capacity, this only meets 2% of the country’s power demands. In fact 75% of their power still comes from coal. Clearly more needs to be done in an effort to phase out fossil fuels for renewables. For this to happen, renewable energy technologies need to be improved to be able to provide more power and deliver it to the right places. Excellent research has been carried out to bring us the technology we have today. However there are serious problems when trying to use these technologies to supply countries with large quantities of power. Energy storage is a key issue. Sticking with wind, generally the amount of wind is intermittent. This means that there is either no electricity being generated or too much to cope with. Last year in China around a quarter of turbines were left off during the windiest times because the turbines are vulnerable to damage during high winds. Another problem is that the windiest places are generally far away from the cities that require power from them. New advances may provide answers to these issues, but it is difficult to tell if this will be years or decades away. One thing is for certain; China should be commended for taking a step in the right direction. This is an opportunity for other countries to follow suit and develop more renewables.