Fer-de-lance

Originally published in The Manitoban, September 29, 2010

In addition to Cuba and the Bahamas, the Caribbean island chain contains an unassuming little island called St. Lucia. A rainforested, mountainous, volcanic island roughly 43 by 23 kilometers, it was first inhabited by Indigenous peoples from South America early in the 2^nd century. 

“Discovered” by good old Christopher Columbus in 1499, British attempts at colonization begain in 1605 and French attempts in 1667. The island changed hands between British and French 14 times before achieving independence in 1979. Sugar plantations manned by African slaves made up the bulk of St. Lucia's economy in the 19^th century, whereas today the main economic boons consist of banana plantations and tourism. The island is mainly inhabited today by descendents of the early African slaves and has a population of about  

200, 000.

What does beautiful St. Lucia have to do with another great Zoological Investigations article, you ask? Interested readers might pass the hours by reading about theories of Island Biogeography and related concepts, perhaps even a little of Darwin's On the Origin... for good measure or, they might simply choose to take my word that islands, by virtue of their remoteness from the mainland, tend to harbour uniquely adapted, endemic (those which aren't found naturally elsewhere in the world) species and provide a rich grounds for evolutionary processes to take hold, leading to interesting and sometimes really weird organisms and community interactions. Often, island species evolve in a relative vacuum, until oh, let's say European settlers introduce hordes of ship rats ready to devour unsuspecting creatures that have never before faced predation. This, as you might guess, usually has disastrous results for island wildlife and let's not forget what happens when us humans begin settling in and ripping up the land for natural resources and hotels-- habitat loss and destruction, oh my.

So now you want to know what the hell is a fer-de-lance, eh? Well, my Canadian friends, that is a lovely french word for 'spearhead' (or the more literal and less poetic, “iron of the lance”) and refers to an extremely venomous snake that lives, you guessed it, on St. Lucia island in the sunny Caribbean. Also known by it's less beautiful sounding scientific name, Bothrops caribbaeus, the fer-de-lance is one of five species of snake found on the island (one of which is now extinct) and belongs to the family Viperidae (fancy talk for, “it's a viper”).

The fer-de-lance is viviparous, which means that it incubates eggs internally and gives birth to live young; around 60 at a time. Gestating females move in and out of the sun in order to regulate their body temperature and incubate the developing young. They mainly eat birds and mammals, and have even been known to eat those crazy vicious carnivores, the mongooses. Hunting takes primarily at night and the snakes will rear into an S-shape, strike quickly and then retreat while their prey dies a horrible, venomous death. 

Pit vipers such as the fer-de-lance have unique structures called pits that are found in grooves on the head which can detect infra-red radiation (i.e. heat) emanating from their prey. This allows the snakes to quickly and accurately locate their prey in the dark and what's more, the position of the pits is such that it allows for a type of “binocular scent” similar to how our human vision gives us depth perception and helps us to correctly gauge distances (most of the time).

The fer-de-lance is extremely venomous, and is considered by many to be the most dangerous snake of Central and South America. It can inject 105 mg of venom in a single bite (milking the snakes for venom has yielded up to 310 mg) and causes more human deaths than any other reptile. In case you wondered, the lethal dose of venom for humans (based on some undisclosed average weight, I assume) is a mere 50 mg.

The venom contains seven different toxins, including stuff that breaks down cell membranes (allowing that precious content to spill out all over the place and cause general mayhem in your poor, dying body) and proteins. The toxins also cause hemorrhage, internal bleeding, painful swelling, and blood clot formation in humans.

Studies of the fer-de-lance undertaken by the National Forest Demarcation and Bio-Physical Resource Inventory Project have shown these vipers to be at a significant risk of extinction, primarily due to that old beast habitat destruction, coupled with the introduction of invasive species such as opossum (manicou), rats, dogs, cats, feral pigs and mongoose, as well as hunting and chemical pollution from agricultural processes. Fer-de-lance populations have declined significantly in beautiful St. Lucia over the last 50 years, and populations are now restricted primarily to two fragmented portions of the island. 

These snakes are not protected by St. Lucia's Wildlife Protection Act, which was implemented in 1980. Three other species of Fer-de-lance native to islands of Brazil, Bothrops alcatraz, B. insularis, and B. pirajaiare listed by the International Union for the Conservation of Nature (IUCN) as critically endangered and vulnerable (B. pirajai) but the St. Lucia fer-de-lance B. caribbaeus has not yet been assessed by the IUCN.

Zoological Investigations Double Back-to-School Feature: Cormorants & Nighthawks

Originally published in The Manitoban, September 15, 2010

The Double-crested Cormorant

The Double-crested Cormorant (Phalacrocorax auritus) is a large, fish-eating waterbird reaching 2.5 to 3 feet in length with a wingspan of almost 4 feet. They are found in Manitoba and throughout the Great Lakes region. They are one of the birds most frequently rescued by the Prairie Wildlife Rehabilitation Centre, or PWRC (see the science feature article). P. auritus spends its winters in the Gulf of Mexico, flying north to breed during our balmy Manitoba summers. They nest in colonies and incubate their clutch by wrapping their webbed feet around the eggs, which is unusual because most birds incubate eggs by ruffling their feathers around them and developing a brood patch, a featherless area where blood vessels close to the skin's surface provide warmth by bringing arterial blood into contact with the eggs. 

Double-crested cormorants often incorporate garbage and beach junk into their large nests, including parts of dead birds! Not the smartest of birds, P. auritus will sometimes mistake large pebbles for eggs and tries its darndest to hatch them! Those nesting in full sun help keep their chicks hydrated by carrying water in their bills to give to the young, which often leave their nest to hang out in a sort of Cormorant daycare called a creche (pronounced cree-sh), returning to the parent nest at feeding time.

Numbers of P. auritus declined severely throughout the 1950s through 70s as a result of high levels of environmental contaminants such as DDT responsible for the thinning of eggshells in these and other bird species but, you'll be glad to know, their numbers have since rebounded marvelously and the Cormorants no long appear to be in any danger from population declines.

Also of note according to Lisa Tretiak, board member and founder of the PWRC, young Double-crested Cormorants are very, very mean and not at all afraid to use their large, hooked bills in combat with would-be human rescuers! For more information on the wacky behaviour of rescued Cormorants, check out this link to the PWRC blog: http://pwrc.wordpress.com/2010/07/21/double-trouble/

 

The Common Nighthawk

The Common Nighthawk (Cordeiles minor) is not a hawk but a member of the Goatsucker or Nightjar family, which includes other nocturnal birds such as whippoorwills, frogmouths, and oilbirds. In addition to having really cool names they refuse to build a nest but instead lay eggs straight on the ground (or on city rooftops) without even bothering to conceal them. Perhaps as a defense against this shoddy parental care, nestling Nighthawks are able to fly as early as 18 days after hatching and can capture insects on their own within 25 to 30 days. Nighthawks have large mouths lined with sensitive bristles to aid them in catching insect prey during cool-looking aerial dives. They have a reflective structure in their eye called the tapetum lucidum (the same structure responsible for making nocturnal mammals' eyes like your cat's glow when a light is shined on them) that improves vision in low-light conditions. They are about 9 inches long with a wingspan of around 20 inches, and spend their winters in South America unlike the rest of us (goat)suckers. 

Common Nighthawks are also brought to the attention of the PWRC rather frequently, but they are often uninjured. The Common Nighthawk undergoes a daily period of inactivity called torpor, in which the body temperature and metabolism are reduced to conserve energy. Many a concerned naturalist has phoned the PWRC thinking these birds are in need of assistance when really, they are just resting up for an evening of insect massacre! C. minor populations have been in decline, probably due to the combination of heavy insecticide usage, habitat destruction, and increased numbers of predators such as cats, skunks, racoons, and crows. They are currently listed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as threatened, and are a species of special concern under Ontario's Endangered Species Act as of 2007.

Mimic Octopus

Originally published September 8, 2010 (The Manitoban, Vol. 98, No. 4)

Today is the day: back to school. Some of us might be filled with excitement and hope for the thrill of a new year of learning and higher education. Others might be devastated and frightened by the stresses of too many courses and heavy workloads. I am filled with both excitement and dread and the back of my mind is crying out, “I'm not ready!”, but what can you do? Take a deep breath, jump in with both feet and just hope for the best. Perhaps this issue's Z.I. creature of choice can be some form of inspiration to us all. It is the intelligent, industrious, devious and graceful mimic octopus.

The mimic octopus, Thaumoctopus mimicus, was unknown to scientists until its discovery in Indonesian waters in 1998. Mimic octopuses tend to get about two feet long and are a modest brown and white striped sort of colour but like many of their cephalopod friends, they have the ability to change colour by altering the distribution of pigment in their skin. This is a form of communication that can be used to interact with members of the same species or to warn off potential predators. It is also a strategy used to camouflage the animals  and avoid being spotted by predators. Many cephalopods can also modify the texture and consistency of their skin in order to appear flat and smooth like sandy bottoms, or rough and bumpy like a rocky area or coral reef. The mimic octopus takes these abilities to the next level by using a combination of pigmentation and strategic movement and limb positioning to actually mimic other organisms found in its highly diverse environment. 

The mimic octopus imitates many highly toxic animals such as lionfish, flatfish, and even sea snakes. These animals have bold, high contrast colouration that is used to warn potential predators of their toxic nature. The idea for the mimic octopus is that if it can pass itself off as one of these dangerous animals, it will not be chased and eaten by its own predators. Seems like a reasonable thing to do, kind of like wearing those t-shirts with the really buff and sexy body type to fool unsuspecting potential dates at bars, right? The thing is that there is a pretty low risk for humans; if the individual you are trying to fool into going on a date with you realizes that it is not your true buff bod but just a t-shirt, at worst you just won't get a date but, for the mimic octopus, if the poisonous animal imitation is a failure, the mimic octopus gets eaten. Game over.

Surprisingly, scientists haven't yet come up with any really fancy explanations for how this high risk strategy evolved, but there are some fresh ideas going around. New research by scientists from the California Academy of Sciences and Conservation International Indonesia looked at DNA sequences of 35 different species of octopus related to T. mimicus in an effort to shed light on this unique adaptation. Their research suggests that the use of bold colour patterns evolved first in order to shock and frighten potential predators away should the more passive camouflage technique fail. Then, the swimming techniques and arm positioning used to mimic the movements of different species seems to have evolved. Finally, the two appear to have been combined; bold colour patterns while swimming like a lionfish, sea snake, or flatfish, as seen in the mimic octopus today.

This is also the first known example of an organism that mimics multiple different species and what's more, observations have been made of mimic octopuses impersonating the specific type of predator that would be most dangerous to whatever species happens to be threatening the octopus at that time! The high level of intelligence suggested by this strategic mimicry definitely places the mimic octopus in the “smarter than the average bear” category, in this writer's humble opinion.

Much remains unknown about the life history strategies of the mimic octopus. They live on the bottoms of muddy estuarine areas in the Indo-Pacific region and their relatively recent discovery means that there is much more to be learned about these amazing little cephalopods. 

mimic octopus as flounder

Andean Condor

Originally published August 18, 2010 (The Manitoban, Vol. 98, No. 3)

The Andean Condor is the largest raptor in the world. Adults weigh between 20 to 30 pounds and reach a shocking 4 feet in height with a wingspan of up to 10 feet! Condors are a type of vulture and thus feed primarily on dead or dying animals. They will also feed on young or injured animals and raid nests for eggs. Eating is not just a disorganized mess of gut-pulling; the dinner table is remarkably structured with the oldest, dominant male feeding first, followed by all other males, then females and young. Scavenging for a meal by poking your head into rotting carcasses whenever possible is not conducive to good hygiene and this is why the heads of vultures are bald. The Andean Condor may travel over 300 kilometers per day looking for food. They can soar at altitudes of up to 18 000 feet using thermals to save energy. They also save energy by allowing their body temperature to drop several degrees below normal at night. Keeping one's body temperature up to snuff is shockingly expensive. 

Andean Condors are New World vultures that are more closely related to storks than to African vultures. They are the only new world vulture to show sexual dimorphism; the males are larger than females and have big, fleshy crests on top of their heads as well as a white collar of feathers around the neck. Females have bright red eyes. This condor does not have a “voice box” and so is usually silent. They make weird hissing, clucking, or barking type sounds during courtship, at which time males try to impress females by prancing around with their massive wings outstretched. They mate for life and may live as long as 75 years in captivity. Both parents take turns incubating the eggs and raising and feeding their young. Breeding usually takes place every second year (or not at all if food and/or weather conditions are poor) and only one egg is laid. Young do not leave the parents until their second year and do not reach sexual maturity until about 6 or 7 years of age. 

How about a simple mathematical problem to ponder? Assume a 100% survival rate where all young birds survive to adulthood and are themselves able to reproduce. Assume that the point of reproduction is not in fact for pleasure but to replace one's self and spread 'dem lovely genes. If two birds produce one bird every other year, how long would it take to guarantee they replace themselves and thus maintain a stable Andean Condor population? The answer, in a perfect world, is four years and last I checked, it was not a perfect world. Andean Condors have fallen upon hard times. 

The Andean Condor is thought to be hands down the largest flying bird that exists in the world today. What have we got to compete against that? Big brains, pah! Perhaps then jealousy is the reason for this incredible animal's addition to the U.S. Endangered Species list in 1973. More practical reasons might suggest things like over hunting, deforestation, loss of habitat, and pollution. Andean Condors breed relatively well in captivity and many young have been released back into the wild since the 1990s. Radio tracking has shown that many of the released birds have survived to maturity and have themselves begun to reproduce in the wild, yet they are still listed as endangered. 

Andean Condor feathers have been harvested for many purposes: for cigarette holders, warding off nightmares, and by harpsicord makers for...something. Various other body parts have been used by various other people for various other reasons at various times: their bones have been ground to soothe rheumatism, their stomachs have been eaten to cure breast cancer, and their eyes have been roasted to improve human sight.

Now let's all dig out our Much Music Dance mix cds of the 90s and celebrate tentatively. Or you might want to look up the San Diego zoo for more information on their captive breeding and wildlife reintroduction programs.

Dragonflies

Originally published July 21, 2010 (The Manitoban, Vol. 98, No. 2)

Do you remember how much you loved Filmon Fridays when you were a kid? A whole day off school?! Man, it was incredible. What have we got that can compare these days? Lackluster dreams of bringing back the Winnipeg Jets? Perfectly good streets quietly and without fanfare being renamed after football players? Come on, Katz-- I want action. I want novelty. I want good ideas. I want a political platform that includes the introduction of a 'Dragonfly Appreciation Week'.

You might think this a departure from the vision of Zoological Investigations, to write about a common and typically well known animal such as the dragonfly, but there are many wonderful facts about dragonflies that I am willing to bet whole packages of Popeye cigarettes the average person on the street just simply doesn't know. 

For starters, dragonflies have been gracing this lovely old rock with their presence for the last 300 million years! They are thought to be one of the first insects that evolved wings (which are derived from the integument or skin, not the limbs) and the ability to fly. The ancestors of today's dragonfly species had wingspans of 20 to 50 centimetres! Just think about that for a second, will you? Popular belief tells us they were able to grow so freakishly huge because the atmosphere during that period (the Carboniferous) contained way more oxygen than it does today, enabling dragonflies to ventilate such a massive body (no lungs for insects, only spiracles and a tracheal system, thank you). Today there are about 5 000 described species of dragonflies and their close relatives the damselflies. 

 

Next up on the list of Odonatous wonders: those four lovely wings. They can beat them synchronously or individually, allowing such elegant flight maneuvers as hovering, taking off backwards, unbanked turns, rapid acceleration (up to nearly 40km/hr) and basically as far as flight goes, they just own the sky. They can fly in tandem while mating, kind of like those crappy love scenes in the old Superman movies. Dragonflies have compound eyes made up of repeating units of a simplified visual receptor called an ommatidium. They have up to 30 000 ommatidia per eye that receive light from whichever direction they are pointing in, giving them an almost 360 degree viewing field. Their vision is binocular, allowing them to judge distances accurately and they see in colour (except red), UV, and detect polarized light. The eyes are also highly sensitive to motion and can detect movements separated by up to 1/300^th of a second, which would make watching a movie look like a series of still photos. The main downside to this masterpiece of an idea is that because the focus cannot be changed near images appear blurred but with all those other great features, who cares? Most things tend to look worse up close anyhow, except perhaps lady dragonflies. 

 

As most of us know, dragonflies are voracious predators of other insects in the adult stage, but they are also magnificent killers during their juvenile, or nymph phase of life, which can last anywhere from months to several years in different species. Dragonfly nymphs hang out in the water, eating most anything they can catch with their big, nasty extensible jaws (think Alien). They've even been known to bite humans. They breathe through gills in their rectum, which makes me giggle but don't get me wrong, I respect the hell out of dragonflies. On the subject of rectum, the nymphs can propel themselves suddenly by rapidly ejecting water out of their anus, like some kind of super-fart sneak attack.

Is this sampling not enough to convince you of the merit Dragonfly Appreciation Week holds? Well, dragonflies are all over the place in folklore because they are historically known for being super badass and way cool. In Romania, dragonflies were said to be horses possessed by a devil and in Sweden, folklore states that the devil uses the dragonfly to weigh people's souls. With the number flying around in my backyard these days I can't tell if it's a good or a bad sign, but I am a bit nervous after hearing that one.

Dragonfly larvae are aquatic

Adult dragonflies are not.

Northern short-tailed shrew

Originally published June 23, 2010 (The Manitoban, Vol. 98, No. 1)

Hello again readers of the Manitoban and welcome to late June. It is just about that time to start planning your doom — I mean future — for this fall and what better way to get back into the swing of things but by learning a little about something even smaller and more insignificant than most of us generally think ourselves to be. Let us examine Blarina brevicauda, the northern short-tailed shrew. This little buddy is only about 120 mm long and weighs no more than 30 grams.

Whilst backpacking about the scenic Canadian countryside this summer, you might expect to meet Blarina in any one of the southern parts of the provinces, from breathtaking Saskatchewan all the way east to balmy Nova Scotia. As usual with any summer vacation, it is best not to get too friendly with strangers, especially considering the Northern short-tailed shrew is the only poisonous mammal in North America.

These shrews use venom produced by the salivary glands along grooves in their teeth to subdue their prey, which are primarily invertebrates but also include small mammals and amphibians. The venom keeps the prey alive yet immobilized for convenient, hassle-free meals. Shrew venom contains both neurotoxins that cause paralysis as well as hemotoxins that prevent blood clotting, destroy red blood cells and generally make a big mess out of the internal organs. One “highly reliable” source — Wikipedia — states that the venom of Blarina brevicauda, when intravenously injected, is enough to kill 200 mice. What kind of mice and how many died in quest of that most valuable information remains a mystery to me.

In general, shrews are small, terrestrial mammals that forage almost continuously for food to satisfy their raging metabolic needs. They must eat up to 90 per cent of their own body weight each day in order to survive, especially in the frigid wasteland us Winnipeggers call home. In fact, these little buggers are so dedicated that they don’t even bother to hibernate. They just run around like mad all winter in a desperate search for food.

Next to eating, the shrew’s favourite pastime is, you guessed it, sex. Females can have up to 10 litters per year, assuming they manage to survive that long. Shrews live to around 30 months of age but just over 10 per cent of individuals manage to make it past their first year. They have poor vision but excellent senses of smell and hearing. In fact, our friend Blarina uses a form of echolocation — just like your friends the bats and whales — in order to travel speedily along the burrows it digs under grasses and packed snow. The only other terrestrial mammals known to use echolocation are tenrecs but you’ll have to look them up for yourself because this is usually just a one-animal-per-issue kind of deal.

It turns out that shrews and I have a lot more in common than I thought. But I still don’t know what the hell Shakespeare was talking about!

Valentine's Day Double Feature

Originally published February 10, 2010 (The Manitoban, Vol. 97, No. 21)

Kissing Bugs

Rhodnius prolixus is one of several species of blood sucking insects belonging to the order hemiptera that can be found from southern Mexico to northern South America. With strong jaws, a powerful bite, and sucking mouthparts specialized for drinking blood, this fiend also produces and secretes proteins into the wounds it makes that function to increase blood flow to the wound site. This allows the animal to get more blood more quickly (kind of like pulling up at a drive-thru and ordering extra-large...or maybe it's more like holding up the drive-thru). 

"So the jerks drink blood, but why call them kissing bugs", you want to know. The clever little devils get the name because they often bite humans and other victims such as cats, dogs, rats, and other hapless mammals on the lips or face (and while they're sleeping to boot). However, unlike your typical fantasy Romeo (or Juliet, or Prince Charming, or Ted Bundy, or whoever), these six-legged freaks also defecate as they kiss (bite). The wound swells, becoming itchy and irritated, and what do you do? Exactly what you shouldn't you fool, which is to scratch the damn thing and rub poop all into your love-bite. Aside from being totally gross (and this is really important, especially if you are planning a budget South American holiday this "spring break"/"reading week") these kissing bugs are discourteous enough to leave you with a little surprise in their fecal matter that goes by the name of Trypanosoma cruzi, perhaps better known as Chagas disease or American sleeping sickness. 

Once infected with this flagellated¹ protozoan parasitic disease you might at first notice only swelling around the wounded area, perhaps a bit of fever--in short, nothing much to write home or see a doctor about. Yet things get sinister once chronic symptoms start to develop: malformation and inflammation of the intestines and heart, and damage to the nervous system occur. There is not yet an effective cure for Chagas disease but there are also educational programs and vector control measures (i.e. spaying insecticides) in place where Chagas disease is common.

R. prolixus gets a pretty bad rap overall, what with killing thousands of humans each year and causing much pain and suffering, but there is something to be admired in an animal so stealthy and ingenious as this one. At least, this writer thinks so. 

If you are planning a holiday this winter, keep in mind that a date with Rhodnius is kind of like having unprotected sex with a stranger folks; there's no telling how much trouble you might get into--so pull down your mosquito net, buckle your pants up extra tight, and watch out for that bad old Rhodnius this Valentine's day!

¹ A flagellum is kind of like a tail.

Venus Flower Basket

The stunningly beautiful venus flower basket is nothing like a kissing bug. The venus flower basket, Euplectella aspergillum, is a type of glass sponge that lives anchored to the sediments in deep ocean waters anywhere from 40 to 5,000 metres deep in the tropics of the South Pacific. It belongs to the class of sponges called Hexactinellida because its skeleton is made of long filaments of silica called spicules that have a six-pointed radial geometry. 

The fine silica fibres produced by Euplectella are of particular interest for fibre optics research because of their ability to transmit light in a similar (but superior) fashion to that used in modern telecommunications fibre optics. Commercial fibre optics require manufacturing under high temperatures but because the glass sponges create fibres under lower temperature they contain ions such as sodium that enhance their fibre optic properties, something we humans haven't yet figured out how to do. The fibres of the sponges are stronger than those used in modern fibre optics as well. The construction of the sponge is also of interest because of the unique arrangement of the fibres, which are laid down in concentric horizontal, vertical, and diagonal layers of varying thickness (from nanometres to centimetres). The result is an incredibly strong but delicate frame that is highly resistant to cracks and breaks. 

Fibre optics might only romantic in the form of those flashy Valentine's cards and construction workers might be sexy to some, but I'll bet their bosses (the ones who nerd about on computers and in labs with sponges looking for stronger ways to erect office buildings) aren't, so why are you reading a Valentine's special on Venus flower baskets and what am I talking about? Shrimp. And I don't mean those cheap rings you get from Safeway.

While Euplectella is busy growing up into a strapping young adult sponge, a young pair of shrimp belonging to the family Spongicolidae sometimes move into the base of Euplectella's cone as it grows. The shrimp graze on particulate food matter that the sponge wafts in through it's flagellated (there's that word again) water chambers, do a bit of cleaning, and generally just loaf about, happily in love. Euplectella keeps growing, and eventually a covering or cap is formed at the top of the cone, trapping the shrimp within the sponge. 

Nonplussed, the happy couple proceed to mate and release their young larvae, which are small enough to fit between the latticework of the sponge, out into the great blue deeps. A mated shrimp pair thus spends their entire life within the sponge and for this reason, Venus flower basket carcasses were traditionally given as wedding presents in Japan and the Philipines, to symbolize either eternal love, eternal imprisonment, or both!