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Today let us appreciate a fearsome tree! The Sandbox tree (Hura crepitans) is a native of the spurge family (like poinsettias and baseball plants). However the Sandbox tree is not a tiny houseplant: it can grow to 60 meters (200 feet) tall and has majestic oval leaves that measure 60 centimeters (2 feet) across. The tree originated in the super competitive biome of the Amazon rainforest, but it has been spreading North through tropical Central America, and invasive colonies have a foothold in tropical East Africa.
The bark of the sandbox tree
Perhaps the somewhat anodyne name “sandbox tree” has you picturing a lovable tree for a children’s nursery or something. Dispel that rosy picture from your mind! Hura crepitans is a monster plant in every way. Not only is it 60 meters tall, its trunk is covered in enormous sharpened spines which would make a Clive Barker villain cry. If you hack through the spines to injure the tree, the sap turns out to be a milky caustic poison which has been used by indigenous hunters to tip arrows and (allegedly) to kill fish. The tree grows a fruit which looks like a vile pumpkin made of hardwood. These jabillo fruit are toxic, but they are not meant to beguile animals into devouring the seeds anyway. Instead they explode like hand grenades causing a raucous bang and throwing seeds 50 meters (150 feet) from the tree.
So why is this giant, spiny, exploding, poisonous tree called the sandbox tree anyway? We don’t call rhinoceroses “playground ponies”. It feels like there has been a substantial nomenclatural failure here (at least in terms of the English common name). As it turns out, during the 19th century, the symmetrical green jabillo pods were harvested, dried out, and sawed into little dishes which were filled with pounce. Pounce is powder made of pulverized cuttlefish bone which was sprinkled on crude paper of yesteryear to size it (i.e. to make it possible to write on) or to dry the heavy ink lines from nibs and quills. Wow! It is easy to forget that people of yesteryear were as freakish in repurposing natural materials into household items as we are with our endless disposable plastic goods.
The Amazon is the planet’s largest river. The great waterway is very much in the news this week as the world turns its eyes to Brazil to watch the Olympics. My whole life I have wanted to visit the upstream backwaters of the Amazon and view its ecological treasures before it is all converted into strip malls and low-cost parking. Unfortunately, the developers are doing a lot better in this life than I, so I am not sure that will ever happen. Thus, instead of going to Brazil in the real world, we will go there via blog! No need for visas (I hear that Brazil doesn’t really want American visitors anyway). We can check out the amazing fish, snakes, mammals, and, um, emperors of Brazil without ever leaving the internet.
No!
Speaking of fish, the Amazon is the home of the fearsome pirarara! No freshwater fish is more storied or more…wait “pirarara”? What the heck is that?\
The Pirarara is actually a giant extremely colorful catfish which grows to immense size (You knew I couldn’t get through these Olympics without writing about some of the magnificent siluriformes from the place with the greatest diversity of catfish….a place where catfish are actually found beneath the water table).
The pirarara (Phractocephalus hemioliopterus) aka “the redtail catfish” is the only living representative of the genus Phractocephalus. These catfish are omnivores which grow to 1.8 meters (six feet) in length and weigh up to 80 kg (180 lb). I wonder if they wear the same sized suits as me? I am being silly, of course: these catfish do not wear suits since nobody has found a pattern which does not clash with their brown backs, mustard yellow sides, and white stomach….and their bright ketchup-red tails. The pirarara should really be called the condiment catfish. The fish are popular in large aquariums, although they are so voracious that they can injure themselves by swallowing aquarium furniture and vomiting it back up.
Redtail catfish may be the last living members of the Phractocephalus genus, but there were once many species…some of which date back to the upper Miocene (13.5 million years ago). They lived throughout what is now Brazil, Ecuador, Venezuela, Guyana, and Ecuador, in the great series of lakes and wetlands which made up the long-vanished Pebas mega-wetland. The pirarara has a certain prehistoric look to it. Can you imagine the crazy color combinations which its vanished realtives must have had as they sw3am among the super crocodiles and crazy alligators of the Pebas?
The Amazon River is the world’s largest river and it has the world’s largest drainage basin—the vast Amazon rainforest, which stretches from the Andes in the west, to the Guiana Highlands to the north and the Brazilian Highlands in the south. The great river drains east into the Atlantic Ocean….but it was not always so. Before the Andes Mountains rose, the river drained west into the Pacific. Throughout the Cenozoic, the mouth of the river moved up around the continent. Thirteen million years ago, during the Miocene, the river drained north into the Caribbean through a huge tropical swamp–the Pebas mega-wetlands–which covered over one million square kilometers of what is now the Amazon Basin.
An illustration of Pebas Corocodilians–Gnatusuchus is underwater, gobbling clams (art by Javier Herbozo)
Like today’s Amazon Basin, the Pebas mega-wetland was a great riverine rainforest. And yet the ecosystem was very different from what is there today. The marshes and swamps were filled with bivalve mollusks that thrived in the oxygen-poor waters. Predators evolved to feed on these clams and mussels…and what predators! This is Gnatusuchus, a caiman with spherical teeth for crushing open shellfish. Can you imagine biting through the shell of a clam? Just thinking about it makes my jaw hurt and my teeth feel broken. Yet Gnatusuchus bit through heavy shells for every meal!
A life-sized reconstruction of the gigantic Purussaurus
The crocodilian grew to lengths of 1.5 meters (about 5 feet) and had a short round shovel-shaped mouth to focus maximum force on biting through clams. Life in the Pebas was not all basking and clam feasts for Gnatusuchus. The reptile was hardly the only reptile in the swamp, but was instead one genus among a hyper-diverse group of crocodilians including giant toothy predators capable of eating Gnatusuchus. One of these predators, Purussaurus neivensis grew to be 12.5 metres (41 ft) in lengt—making it a rival of the great Mesozoic crocodilians like Phobosuchus (maybe I should have mentioned this horrifying monster first, instead of alluding to him after the clam-eater, but Ferrebeekeeper is interested in mollusks and their predators not in giant crocodiles: this is not Peter Pan, my friend). There were also piscivorous crocodilians with long scissor snouts foll of hooked teeth (like modern gharials), and even little crocodilians on stilt-like legs that ran around plucking up small prey in the manner of pipers or herons.
Seven million years ago, the Pebas began to change from swamps to channels as Amazonian drainage became spread through an even more enormous basin. Still, the diversity of the creature that lived there became a heritage for the contemporary Amazon, arguably the most diverse ecosystem in the world today.
The Amazon River is renowned for having the greatest diversity of catfish of any river—oh, and it is also the largest river in the world too, I guess. The river drains half of South America and its branches flows through many many different sorts of regions. Near Tena in Ecuador, the river’s tributaries flow through a karst landscape of sunken limestone caves, streams and springs. There, deep beneath the rainforest, scientists have discovered a catfish with a remarkable ability to climb walls—or perhaps I should say they have rediscovered a previously known fish and found out it has unexpected talents.
The cave-climbing catfish (photograph by Geoff Hoese)
A team of naturalists led by Geoff Hoese found the catfish in a subterranean waterway jauntily climbing up a sheer 3 meter (10 foot) stone wall with a thin rivulet running down it. Here is a link to a National Geographic article about the catfish—you can go there and watch a video of the catfish shimmying up and down water-slicked rocks. The scientists believe the fish is Chaetostoma microps, a member of the suckermouth armored catfish family (Loricariidae), a group of animals which Ferrebeekeeper has enthused about in past posts (although the fish’s identity remains unclear—since the team had no permit for taking specimens and left the creature unmolested still climbing its underground walls).
An illustration of Chaetostoma microps
Chaetostoma microps is not notably specialized for cave life—it still has pigment and eyes, and lacks the marked asceticism of other true underdwellers like the pink catfish Phreatobius cisternarum (which lives beneath the water table!) Chaetostoma microps feeds on algae—which is notably lacking from underground caves. So what exactly is the fish doing down there? And how/why did it evolve its remarkable ability to climb rocks without much water? The answers are unclear, but it seems reasonable to assume that a fish from the vertiginous yet cave-studded foothills of the Andes would need the ability to climb in order to maximize its habitat (and to prevent being sucked into an inescapable underground grotto). Maybe Chaetostoma microps is really a mountaineer catfish. Instead of leaping like salmon, it deals with its rocky treacherous home by suction, barbels, and indomitable spirit!
CD Catfish (Tim Vogelaar and Joel Smythe for “Nashville Catfish out of Water”)
I suspect that ever since the color of the year was announced to be radiant orchid, my readers have only been asking themselves one question: “Are there any purple catfish?” There are many imaginary purple catfish in the arts and in fantasy (and in a world of fluorescent lights, all sorts of things can take on a lavender hint), but there is also a real purple catfish! Native to the clear flowing streams of Guyana, here is Centromochlus reticulatus, also known as the purple oil catfish or the driftwood cat.
Centromochlus reticulatus (image from msjinkzd)
Centromochlus reticulatus is a shy and retiring catfish which likes to hide by day in driftwood and come out at night to feed on whatever tiny invertebrates or other foodstuffs they can find. The adult fish are extremely tiny and measure only 1 inch (2.7 cm) in length. Like many little catfish, the fish may be shy and nocturnal but they are also social and friendly with each other. Indeed aquarists report that they can sometimes be seen coming out to feed in little pseudo-schools where they frisk and dance in happiness at being together. Their most distinctive traits are the handsome honeycomb spots on their backs, their long whiskers, and cute all-black eyes (which are covered in adipose tissue and “lack orbital rims”). Because they are so furtive, their wild range is somewhat unclear: although they are most common in Guyana’s Rupunun River, they reputedly also live in various nearby South American waterways (including the northeastern tributaries of the mighty Amazon).
Young Centromochlus reticulatus
The little fish are not exactly a Pantone dream color: younger fish are a demure purple/pink (although in older specimens the purple may fade somewhat). And yet I find the tiny lavender catfish to be very endearing.
Chullachaqui (painting by David Hewson)
If you are wondering through the great untouched rainforests of the Amazon basin, you will sometimes come across a clearing devoid of all vegetation save for a few trees. These bare patches are known as devil’s gardens and are said to be the haunt of the fearsome Chuyachaqui (or Chullachaqui), a shape shifting demon which delights in causing misfortune to travelers. Although the Chuyachaqui’s default form is that of a small misshapen man with one hoof and one human foot, the demon can change shape into a person known to the traveler in order to mislead the latter to doom.
Lemon ants (Myrmelachista schumanni), so named because they are said to have an acidic lemony taste
Scientists were curious about these small bare patches of forest. After carefully studying the ecosystem, they discovered that a force nearly as diabolical as the Chuyachaqui is responsible. The lemon ant, Myrmelachista schumanni, produces formic acid, a natural herbicide which it methodically injects into the plants in a “devil’s clearing”. The only plants which the ants leaves alone are Duroia hirsuta, “lemon ant trees” which have evolved a mutualistic relationship with the ants. The lemon ants keep the forest free of competing trees and plants, while the lemon ant tree is hollow inside—a perfect natural ant hive and its leaves provide a source of nutrition for the lemon ants (which are a sort of leaf-cutter).
A clearing filled with lemon ant trees
Large colonies of lemon ant trees have been found which are believed to be more than 800 years old—far older than the life of any ant colony or individual tree. It is remarkable to think these ant/tree settlements have been part of the rainforest since before the Mongol conquests.
The Piraiba (Brachyplatystoma filamentosum)
Today features a short post concerning one of the strangest looking groups of catfish—which is truly saying something since the entire order of catfish appears rather odd. Brachyplatystoma is a genus of catfish from central South America which includes the largest catfish from that continent, Brachyplatystoma filamentosum, the so-called Goliath catfish or Piraiba, which is capable of reaching up to 3.6 metres (12 ft) in length and can weigh up to 200 kg (450 pounds). The Piraiba is hunted for food and sport both with hooks and with harpoons. All Brachyplatystoma catfish are swift sleek fish which live by hunting, but whereas the other species mostly hunt fish, the Piraiba has been known to eat primates. Specimens have been found with monkeys in their digestive system and attacks on humans are darkly rumored (although ichthyologists scoff that the mighty fish only scavenges the remains of such terrestrial animals).
Brachyplatystoma capapretum (photo by Enrico Richter)
The other Brachyplatystoma catfish species are smaller than the giant Brachyplatystoma filamentosum, but they all have the elongated flattened nose which characterizes the genus. One of these species, B. tigrinum, has especially lovely stripes. Although an unusual fish, it is caught in sufficient quantities to be available in specialty stores for home aquariums, where its long nose, pretty stripes, and interesting behavior fetch a premium price.
Brachyplatystoma tigrinus (Zebra shovelnose catfish)
Brachyplatystoma tigrinus
Since I have already written so many mammal posts I am creating a new blog category for mammals (I will leave out human concerns to concentrate on zoologic overviews of other species, but please remember that technically we too are mammals and all of the posts on this and every website could fall under this category). To make way for the mammals I deleted the “celebrity” topic for good (I had hoped to make fun of our queasy fascination with lackwit celebrities–but other than an one sighting of the disquieting Richard Simmons, I had nothing). Begone vile celebrities! The age of the mammals has dawned.
The Giant Otter, Pteronura brasiliensis
I already have plenty of posts about goats, pigs, wombats, hyraxes, and bizarre intelligent monotremes with which to populate this category, but to kick the topic off properly I am writing today about the alpha-predator of the Amazon. This mammal is the king of the Mustelidae (also known as the weasel family) and, if you have ever seen a lightning fast stoat hunting a rabbit, or smelled a skunk, or watched a badger drive off a bear, or witnessed a wolverine tear apart a moose, you will know that the weasel family is not joking around. [ed: what? When did you see any of this?] The largest mustelid is a particularly magnificent creature—the giant otter (Pteronura brasiliensis) which lives throughout the Amazon basin and Pantanal. The giant otter is a long animal and males are up to six feet (2 meters in length) and weigh up to 100 pounds (45 kilograms). Much longer males measuring nearly 8 feet in length were once reported but it is believed that extensive hunting may have eradicated all of the really giant giant otters.
An Immature Giant Otter held by Wildlife Conservation Worker Diane McTurk in Guyana
Giant otters are tremendously accomplished fishers living largely on cichlids, characins (such as piranha), and catfish, but, as an apex predator they are opportunists who supplement their diet with snakes, crabs, turtles, and caimans. Although the otters are diurnal predators who hunt at daytime using their large acute eyes to find their prey, their hearing is also excellent and they possess extremely sensitive vibrissae (whiskers) to gauge the faintest water current. Like other mustelids, giant otters have fast metabolisms and they eat about 10% of their body weight per day. Their adaptations to aquatic life include webbed feet, ears and nostrils which clamp shut, powerful tails for swimming, and incredibly dense fur. As with their cousins the sea otters, this valuable fur proved to be their undoing. During the nineteenth and early twentieth century they were hunted to the very threshold of extinction by furriers (and by fishermen who regard them as a clever nuisance). Their numbers still remain low today: only 2,000-5,000 giant otters are estimated to live in the wild.
Orphaned Giant Otter Cubs
Giant otters form family groups around a mated pair. Older offspring from years past stay with this pair and help out rearing the young cubs before venturing off on their own. They travel widely through the inundated forest during flood seasons and spend the rest of the year based around a fishing camp which they build beside a lake or a choice stretch of river. These camps consist of large multiple entrance home dens built under and around tree roots as well as several secondary locations (along with communal latrine areas). The otters might also alter river beaches to be more to their liking by removing vegetation. The fur of the giant otter is usually brown, red, or fawn and the otter’s bib is marked with cream and white stipples. These are for identification purposes: otters “persiscope” up out of the water to get a better view of each other and to learn whom they are meeting. Giant Otters are also famous for their complicated (and loud) vocalizations.
A Giant Otter "periscoping" (photo by Roberto Fabbri Wildlife)
Although the adult giant otter has no natural predators, young otters must look out for caimans, jaguars, and anacondas. Additionally the giant otters compete for prey with these creatures as well as with river dolphins, large predatory fish, and large turtles. The otters are always on the lookout for dangerous stingrays and electric eels. None of these natural threats, however, are particularly significant compared with the threat from habitat loss, logging, mining, and industrial pollution.
Some of the native humans indigenous to the great river basins believed the otters were river spirits who had, once taught valuable lessons to the first humans. Other native peoples (particularly fishing people) held that the otters were worthless nuisances to be killed or run off whenever sighted. Such sightings however grow increasingly rare as the giant otter, the longest mustelid, vanishes forever away from all but the wildest places in the rainforest.
A Wild Giant Otter Devouring an Armoured Catfish (photo by Roberto Fabbri Wildlife)
Some things are easy to write about. For example, the world’s largest catfish was an effortless topic—what a great fish! There is plenty of information about the animal and its giant size makes it instantly fun and interesting (although the specie’s widespread decline does bring a sense of mounting unease). For a wide variety of reasons, other subjects are considerably more difficult to address. Sometimes the information is unavailable or the data is lurid and upsetting. In a poignant incongruity, one of these troubling topics happens to be the world’s smallest catfish, the candiru, which hails from the Amazon basin of Brazil.
Vandellia cirrhosa
The term itself “candiru” can mean either the species Vandellia cirrhosa, or it can refer to several genera of similar small catfishes. There is apparently even a genus “Candiru”. To put it bluntly the candiru is a vampire catfish. It enters the gills of larger fishes and sucks their blood–well actually, it doesn’t suck the blood as such. To quote “fishbase” an online fish resource, “[The candiru] bites mostly at the ventral or dorsal aorta arteries, and the blood is pumped into its gut by the host’s blood pressure. It does not need any special sucking or pumping mechanism to quickly engorge itself with blood, but simply uses its needle-like teeth to make an incision in an artery.” The candiru is small. Vandellia cirrhosa rarely exceeds lengths of 1-2.5 in (2.5-6 cm) with a width of 3.5 mm (although much larger specimens are known).
The junction of the Amazon River and the Rio Negro, (near Manaus, Brazil) is the principal haunting ground of the candiru. The catfish hides in the sand or mud. When prey swims by—either in the day or at night—the candiru uses its tremendous sense of smell and powerful eyesight to hone in on the other fish’s gills for a blood meal. The Candiru has backwards pointing spines behind its gill covers. It can lock itself into a victim’s flesh with these razor sharp rays.
The…um…Lovely Beach at Manaus, Brazil
The candiru is not picky about its blood source and this has made it one of the most feared fish in the Amazon. It has been known to enter swimming humans through various orifices or through open wounds. Lurid ethnological reports from as far back as the 19th century detail this fish’s intimate depredations of human hosts.
Argh! Drop those in bleach and go wash your hands with holy water!
It is entirely whimsical—even childish—to speculate about whether the catfish is averse to garlic, possesses immortality, has become a hero to preteen girls, speaks with a strong Baltic accent, etc.
ferrebeekeeper 