Kings of the New World (3): The Black Caiman

by Rob Cooper

Picture a set of black jaws emerging from the water as you stoop to drink; the consummate ease with which they move through the air belaying the sluggish appearance of the creature it belongs to as they close around your throat. Unfortunately this is far from the killing blow. The teeth of crocodilians are designed to grab and hold not to pierce or crush despite there being enough force to shatter bone. You are dragged into the waters of the amazon desperately flailing, held captive by a creature both far more at home and more powerful than you. Your dreaded captor then allows itself to sink dragging you along for the ride. The truth will soon emerge that crocodilians rarely actually kill their prey they simply immerse them in the lethal waterways they call home. The final of the great Amazonian predators is itself a living fossil. The black caiman is one of largest extant reptiles and is the largest predator in the amazon Basin. Akin to all modern crocodiles the black caiman shows little deviance from the genesis of the crocodilians over 200 million years ago. This giant reptile can. In some areas, routinely reach lengths of 4-5 metres and can reportedly reach 6 metres long and weigh over a tonne. 

In an earlier article I highlighted how the Jaguar often preys on the various caiman species in its environments. The black caiman however is the one exceptions. Whilst juvenile caiman are eaten by all manner of predators including snakes, storks and other caimans the adults have no natural enemies other than man and can be up to ten times the size of the Jaguar, putting them firmly off the menu.

As the caiman grow their diet shifts quiet remarkably. Young caimans eat crustaceans and insects than graduate to eating fish such as piranha and catfish and the adults often hunt large mammals that come to drink at the water’s edge such as Tapir, capybara, deer and jaguar. This is an example of different aged animals occupying different niches in order to reduce intraspecific competition (between members of the same species). The advantage of having less competition is that there is more food available to each individual because fewer organisms are taking a share so genes and behaviour promoting this system is perpetuated by natural selection.

Caiman also show a great deal of motherly attention. Mother caiman are well documented to help the hatchlings out of their eggs upon hearing their characteristic squeaking sound from within the egg. The young caiman upon hatching from the nest form a pod that is protected from predators by the presence of a large female. Pods can also contain individuals from other nests who became separated from their siblings. This behaviour has led to a great deal of speculation about the parental habits of dinosaurs as the brains of crocodilians share many features with that of therapod dinosaurs such as Allosaurus and Tyrannosaurus; many more similarities than when compared to birds, the other close relative of dinosaurs.

Unfortunately the black caiman recently nearly went the same way as the dinosaurs. Between 1950 and 1970 (when the species was classified as endangered) hunting decimated the populations in South America in order to collect its commercially valuable hide. Fortunately since then the black caiman populations have been increasing although conservation efforts face a problem when the creature in question is large and dangerous and according to the locals can regularly predate upon humans of all ages as well as dogs and livestock of any size. Normally people tend to be removed from the habitats of the black caiman but some groups such as the Rupununi River people live on the river itself in one of the last strongholds of the black caiman and live their lives fearing attacks from the deep and mourning loved ones lost to the primeval reptiles. Clearly such a struggle between man and beast is not easy to resolve.

The ancient giant Purussaurus

But what makes the black caiman stand out from contemporary crocodiles such as the American alligator or the Nile crocodile? Apart from being the largest member of the alligator family the black caiman in particular has a spectacularly large head even amongst crocodilians. A 3.9 metre long black caiman has a significantly longer skull than a 4.8 metre Nile crocodile. This adaption is thought to be geared towards the taking of larger prey items but there are few statistical studies due to low level of information regarding the black caiman. In addition most caiman species are characterised by large skull sizes without specifically taking large prey items, although other species could be limited by body size. The giant extinct caiman Purussaurus, which died out merely 8 million years ago, took this adaption to its zenith with a titanic 1.4 metre long skull on its 11-12 metre body. The black caiman is the closest organism we have today to such giants.

As I alluded to in the first paragraph the killing strategy of these caiman is something very reminiscent of a horror movie. The kill is not quick or clean; but it is very efficient. The teeth of all crocodilians, the caiman included are conical and sharp but not serrated. These teeth can trap small slippery prey such as fish to be swallowed hole and firmly keep hold of larger prey such as a tapir in order to drag it under water where the prey can be safely drowned without the predator having to grapple too closely with the prey species or evolve ways of killing them. All the caiman needs is its impressive skull and 1900 newton bite force to finish of almost any prey item equipping them to tackle all prey items in their environment including other caimans. 

What can we learn from the black caiman then? Firstly I think it is both thrilling and terrifying to consider the great rainforests of the world still harbour such impressive wildlife. Secondly that conservation isn’t always the simplest matter in the world. It would be lovely if we could protect all wildlife still remaining but the harrowing stories of natives eaten by black caiman remind us of a past time when man really was at the mercy of the bigger, more powerful animals around him. Finally the most positive message is that we can save animal species. One simple change in the law to prevent hunting of black caiman has saved the species from an untimely demise and that is a promising message for the future. For all his capacity to do wrong man also has the capacity to do good. 

Kings of the New World (2): The Green Anaconda

by Rob Cooper

In the modern world snakes are often associated with malice and deception relating back to figures such as the snake from the Garden of Eden and the Medusa slain by Perseus in Greek mythology. But is this reputation deserved? After all, in many lesser exposed cultures, such as those of ancient Egyptians, snakes are esteemed symbols of nature, power and worship and many modern cultures still worship snakes to this day. Perhaps the most infamous of all snakes is the Green Anaconda for its enormous size and power. In this article I will analyse if its malign reputation is well deserved.

The Green Anaconda is generally considered to be the heaviest snake in the world. Whilst the reticulated python can reach 7.5 meters in length a 5 meter anaconda would still outweigh the python.  Anacondas show a large degree of difference in size between the sexes (sexual dimorphism) and the largest individual ever officially measured was a female 521cm long and 97.5kg in weight. It has been estimated that female anacondas have a maximum length of 6.7 meters before they can no longer reproduce. However there are numerous tales of titanic snakes stretching to lengths of 12 meters have been described by travellers. Although it is telling that a $50,000 dollar prize for a snake over 9.1 meters in length is as of yet unclaimed. 

Female anaconda alongside male, showing sexual-dimorphism

Anacondas show remarkable growth over their thirty year life spans and the average adult is 500 times larger than it was as a hatchling. To put that into context the average human new born is 3.4kg making the average adult 1.7 tonnes… If we followed the growth pattern of anacondas, which we fortunately do not. Anaconda mating also brings us to a rather sinister tendency of females to cannibalise males. Even more harrowing (for a male anaconda) is that most cases have shown that the female had recently finished breeding leading to an unsettling hypothesis that opportunistic females cannibalise their mate in order to supply nutrients for the development of the embryo. 

Much like the Jaguar, the anaconda is very at home in water and has both its eyes and nostrils situated on the top of its head allowing it to breathe and see its prey whilst remaining underwater. Belaying their sluggish nature on land anacondas are very strong swimmers although they are often known to drift down faster flowing rivers and swim to the side once they have found a favourable locations. The anaconda eats any species that it can restrain and commonly predates on smaller caiman species, deer, capybara, dogs, sheep, tapir and even Jaguar and humans on occasion, although attacks on humans are very rare. Like all snakes their metabolism is remarkably slow and they can often go one or two months between meals. The record is held by a captive anaconda that didn't eat for an entire two years. 

A member of the boa family (and often known as ‘the water boa’) the anaconda shares a typical attack style with the other members of the family. Firstly the snake latches its jaw onto the prey item in order to pin it between over 100 razor sharp recurved teeth which point back into the snake’s throat keenly preventing the animal from escaping. The snake then wraps first one, then two coils around the prey item. In a nightmarish turn, every time the prey item breathes out the coils tighten making it harder and harder to breathe. An adult anaconda is capable of squeezing with around 65,000 Pascal’s of pressure which is roughly equivalent to having a single decker bus being supported by the human chest (if we assume humans as the prey item in question). This, it hardly needs saying, is rather impressive for any animal, let alone one that is relatively small. The force that the enormous titanaboa (extinct snake, estimated at over a tonne in weight) could have exerted hardly bears thinking about. 

Documented attacks of anaconda on humans are rather rare which is perhaps due to low population density in areas were anacondas are common and their habit of hunting nocturnally in the water which limits the human contact they receive. However there are several recorded attacks on field researchers. These attacks also seem to be predatory as the snakes are not disturbed prior to the attacks and were known to follow the target for several meters still submerged and so able to make a safe escape. It is also often the case that large disturbed snakes are often docile and rarely try to bite even when handled, although they will resist when being restrained and moved. The snakes also seem picky with targets, so far the only recorded attacks have been on smaller individuals who fall inside the weight range of anaconda prey and larger individuals have been ignored possibly due to being too large for the anaconda to swallow. All documented attacks have also occurred in areas that are seldom travelled by people. 

This suggests that the anaconda seems to have no fear of predating on people, which a trait uncommon to most mammalian predators yet strangely manifested in some reptilian predators such as crocodilians. Does this suggest that the anaconda is the monster that it is made out to be by the numerous horror films snakes feature in? I would maintain not. The anaconda is simply a generalist and humans, which it encounters rarely, which happen to fall within its prey size range are simply a good way of recovering the energy deficit inflicted by giving birth or from long periods of starvation. 

The anaconda is a remarkable and terrifying creature but should it not be the goal of man to be able to look past simple emotional reactions and remember that, whilst intimidating, the anaconda has a majesty all of its own and is an animal just like any other and if any form of right to life exists the anaconda is just as deserving as we are.

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!