Posts tagged snake

Male Reproductive Organ - Lachesis rhombeata (now Lachesis muta rhombeata)

Like other Squamates (snakes and lizards), the male Atlantic forest bushmaster (Lachesis muta rhombeata) possesses a reproductive organ known as the hemipene, or hemipenis. It has two heads, and is generally heavily spiked on both heads. The organ retracts into the tail of the animal when it’s not mating, and is one of the defining characteristics of the order Squamata.

Recuil de Planche coloriees d’Animaux du Bresil, publie par S. A. S. le Prince Maximilien de Wied-Neuwied. 1822.

Boomslang - Bucephalus viridis [now Dispholidus typus] Where the elapids and viperids have fangs at the front of their mouth for easy envenomation, boomslangs (a member of the Colubrids) are equipped with regular teeth at the front of their mouth, and venom-injecting fangs at the back. Because of this, even though their venom is extremely hemotoxic, they rarely are able to inject enough into a larger animal (such as a human) to cause death. However, the bite of a boomslang is not to be underestimated - as it’s not always clear when the fangs have punctured the skin due to the other teeth leaving puncture wounds, medical help should always be sought out. The venom is almost completely hemotoxic, and the lack of neurotoxic symptoms can lead bite victims to believe that there was either no envenomation, or that they can just wait for their body to process the toxin. This mindset is what led to the 1957 death of esteemed herpetologist Karl Schmidt. He believed that the amount of venom he received was negligible, but 28 hours later his blood was so thin that it was coming out of every hole in the body, including his eyes and ears, and no amount of medical treatment could have saved him. Early antivenin administration is critical. Luckily, even if you’re in its natural habitat (forested areas in sub-Saharan Africa), you will probably never encounter a boomslang in the wild. They’re timid, generally dwell in trees more than 20 feet above the forest floor, and would much rather eat a small bird than waste their venom on a human. Most bites occur when someone tries to handle or kill one. Illustrations of the Zoology of South Africa: No. XXII. Andrew Smith, March 1845.

Boomslang - Bucephalus viridis [now Dispholidus typus]

Where the elapids and viperids have fangs at the front of their mouth for easy envenomation, boomslangs (a member of the Colubrids) are equipped with regular teeth at the front of their mouth, and venom-injecting fangs at the back. Because of this, even though their venom is extremely hemotoxic, they rarely are able to inject enough into a larger animal (such as a human) to cause death.

However, the bite of a boomslang is not to be underestimated - as it’s not always clear when the fangs have punctured the skin due to the other teeth leaving puncture wounds, medical help should always be sought out. The venom is almost completely hemotoxic, and the lack of neurotoxic symptoms can lead bite victims to believe that there was either no envenomation, or that they can just wait for their body to process the toxin.

This mindset is what led to the 1957 death of esteemed herpetologist Karl Schmidt. He believed that the amount of venom he received was negligible, but 28 hours later his blood was so thin that it was coming out of every hole in the body, including his eyes and ears, and no amount of medical treatment could have saved him. Early antivenin administration is critical.

Luckily, even if you’re in its natural habitat (forested areas in sub-Saharan Africa), you will probably never encounter a boomslang in the wild. They’re timid, generally dwell in trees more than 20 feet above the forest floor, and would much rather eat a small bird than waste their venom on a human. Most bites occur when someone tries to handle or kill one.

Illustrations of the Zoology of South Africa: No. XXII. Andrew Smith, March 1845.

Ways to Die: Snake Venom

The vast majority of snakes that one encounters in the wild (unless you live in Australia or India) are either non-venomous to humans or want nothing to do with you.

However, should you stumble upon a rattlesnake nest or coral snake hole while texting in the middle of nowhere, there will probably be a combination of different enzymes and polypeptides pumped into your body, via the modified parotid salivary glands (right below the ear in humans) that snakes have evolved over the ages, to disable their prey. Of course, you’re not prey, but you stepped on a snake while texting. It has every reason to envenomate you.

While all snakes have multiple active enzymes in their venom, all snakes dangerous to humans have either neurotoxins or cytotoxins as a significant component in their venom. For the most part, elapids (such as the cobras and mambas) create neurotoxins, while the viperids (such as vipers, adders, and rattlesnakes) create cytotoxins.

Neurotoxins

  • Dendrotoxins: Inhibit neurotransmission by blocking the exchange of positive and negative ions across the pre-synaptic neuronal membrane, causing paralysis. Found in some rattlesnakes (such as the Mojave) and mambas.
  • Fasciculins: Destroys acetylcholinesterase (AChE) in synaptic clefts of nerves. Without AChE, acetylcholine (ACh) is not broken down, and remains bound to the postsynaptic vesicles of the nerve, leading to constant contraction of the related muscles. This is called tetany or tetanic paralysis. Found only in mambas.
  • α-neurotoxins: Very large group of toxins that mimic ACh and bind to post-synaptic vesicles, leading to numbness and paralysis. Found in cobras, kraits, and sea snakes. 

Cytotoxins

  • Cardiotoxins: Target muscle cells and cause depolarization. If enough of these components reach the heart, the depolarization can cause irregular heartbeat or spontaneous stopping of the heart. Can cause fasciculations in skeletal muscles. Found in the Naja genus, and in King Cobras. Minor but important component of mamba venom.
  • Phospholipases: Proteins that target the phospholipid bilayer of cells, causing cellular rupture. Can cause extreme blistering at site of bite. Relatively uncommon, found in the Japanese Habu.
  • Hemotoxins: Burst red blood cells (hemolysis), causing thin blood, internal bleeding, and blood clots due to the massive clotting response. Found to some degree in almost all vipers, as well as some cobras.

Images:
Top: Bungaris fasciatus - Banded Krait. An elapid, and the largest of the kraits. Has neurotoxic venom. [source]
Center Right: Hydrophis robusta [now Hydrophis spiralis] - Yellow Sea-Snake. The longest sea snake, at 3 m (9.8 ft). A member of the Hydrophiinae, separate from other elapids. Though they have some of the most toxic venom in the world, bites are extremely uncommon and often unnoticed. [source]
Center Left: Vipera russellii - Russell’s Viper. A particularly aggressive viperid. Necrosis and amputation following envenomation not uncommon, due to hemolysis and local cell damage. [source]
Bottom: Vipera caudisona [now Crotalus horridus] - Timber Rattlesnake. A venomous viperid endemic to the United States. Primarily hemotoxic venom, very low fatality rate, but very painful bites. [source]

“Death”Gaboon Viper - Bitis gabonica Despite the fact that the Gaboon viper ends up on many of the lists of “World’s Deadliest” or “Most Dangerous” animals, it’s actually not anywhere near the threat that you might think. Similar to the Australian sea snakes (with some of the deadliest venom), its docile nature renders the fact that it produces the highest volume of venom much less of a threat than, say, an aggressive snake with a small amount of venom. Granted, you shouldn’t go around picking these guys up or threatening them, but they don’t chase down intruders or threats. Bitis gabonica is the largest of its genus (commonly known as the puff adders), and at 8.5 kg (19 lbs), is the heaviest viperid in the world. If they do manage to get a bite on someone, the hemotoxic venom can cause internal bleeding, shock, local blistering, and eventually necrosis and the need for amputation, if not treated immediately. ETA: Apparently the Gaboon viper also has the longest fangs of any species, and that, combined with the fact that they produce the most venom and that when they DO bite, they inject venom about 3/4 of the time (as opposed to 1 in 4 times for most viperids), is why they end up on all of these “most deadly” lists. I guess it fits. Docile and chill creature overall, but don’t piss it off or you’ll be hurting. The Uganda Protectorate. Sir Harry Johnston, 1902.

“Death”

Gaboon Viper - Bitis gabonica

Despite the fact that the Gaboon viper ends up on many of the lists of “World’s Deadliest” or “Most Dangerous” animals, it’s actually not anywhere near the threat that you might think. Similar to the Australian sea snakes (with some of the deadliest venom), its docile nature renders the fact that it produces the highest volume of venom much less of a threat than, say, an aggressive snake with a small amount of venom.

Granted, you shouldn’t go around picking these guys up or threatening them, but they don’t chase down intruders or threats.

Bitis gabonica is the largest of its genus (commonly known as the puff adders), and at 8.5 kg (19 lbs), is the heaviest viperid in the world. If they do manage to get a bite on someone, the hemotoxic venom can cause internal bleeding, shock, local blistering, and eventually necrosis and the need for amputation, if not treated immediately.

ETA: Apparently the Gaboon viper also has the longest fangs of any species, and that, combined with the fact that they produce the most venom and that when they DO bite, they inject venom about 3/4 of the time (as opposed to 1 in 4 times for most viperids), is why they end up on all of these “most deadly” lists. I guess it fits. Docile and chill creature overall, but don’t piss it off or you’ll be hurting.

The Uganda Protectorate. Sir Harry Johnston, 1902.

biomedicalephemera: Method of the mussurana’s attack upon the jararaca. Note the size difference between the two snakes. The mussurana is able to consume comparatively large snakes because its digestive system compresses the body of the other snake into a wave-like shape. Through the Brazilian Wilderness. Theodore Roosevelt, 1914.

biomedicalephemera:

Method of the mussurana’s attack upon the jararaca.

Note the size difference between the two snakes. The mussurana is able to consume comparatively large snakes because its digestive system compresses the body of the other snake into a wave-like shape.

Through the Brazilian Wilderness. Theodore Roosevelt, 1914.

biomedicalephemera: “The mussurama [mussurana] swallowing the jararaca, or fer-de-lance, after having just killed it.” “Look men, NATURE!”  The mussurana is an ophiophagous snake, meaning that it specializes in eating other snakes. It has around 15 strong teeth in the back of its mouth that it uses to pull the head of the  (still living) other snake into its gullet, at which point it wraps around its prey and strangles it. This behavior leads it to be called a “pseudoboa”. Mussuaranas are immune to the venom of their prey - the pit vipers of Central and South America. However, the coral snake venom is still deadly to them. Through the Brazilian Wilderness. Theodore Roosevelt, 1914.

biomedicalephemera:

“The mussurama [mussurana] swallowing the jararaca, or fer-de-lance, after having just killed it.”

“Look men, NATURE!” 

The mussurana is an ophiophagous snake, meaning that it specializes in eating other snakes. It has around 15 strong teeth in the back of its mouth that it uses to pull the head of the  (still living) other snake into its gullet, at which point it wraps around its prey and strangles it. This behavior leads it to be called a “pseudoboa”.

Mussuaranas are immune to the venom of their prey - the pit vipers of Central and South America. However, the coral snake venom is still deadly to them.

Through the Brazilian Wilderness. Theodore Roosevelt, 1914.

Funniest or oddest natural remedy — Asked by dwarvesandtheirblogger

This may be taking “funny” in a bit of a dark way, but Pliny the Elder used to tout oleander as a cure for snakebites.

Not only does it not work at all, but it actually intensifies the symptoms of neurotoxic venoms, and is straight up deadly on its own, let alone given to an already envenomed person.

I always found it funny, because the direct translation of his writings state that the oleander flowers and leaves can “cease the symptoms from the bite of the snake”. Which, yes, they can! By killing you! No symptoms, then!

Graceful small-headed sea snake - Hydrophis gracilis [now Microcephalophis gracilis] The graceful small-headed sea snake, or slender sea snake, is one of the members of the Hydrophiidae, a family of highly-venomous seafaring reptiles. Though they can function on land, many members of this species spend effectively their entire life at sea. Their habitat - the Indian Ocean, South China Sea, and Persian Gulf - has an average water temperature high enough to allow these snakes to not need any time “sunning” themselves. Despite their highly venomous nature, most sea snakes (including this species) are very placid. They rarely bite, even when threatened - not that I’d advocate you approaching one! - but as they must hunt fish that are faster than them in the water, their venom is potent enough to immediately immobilize and kill even their largest prey. Transactions of the scientific meetings of the Zoological Society of London. 1841.

Graceful small-headed sea snake - Hydrophis gracilis [now Microcephalophis gracilis]

The graceful small-headed sea snake, or slender sea snake, is one of the members of the Hydrophiidae, a family of highly-venomous seafaring reptiles. Though they can function on land, many members of this species spend effectively their entire life at sea. Their habitat - the Indian Ocean, South China Sea, and Persian Gulf - has an average water temperature high enough to allow these snakes to not need any time “sunning” themselves.

Despite their highly venomous nature, most sea snakes (including this species) are very placid. They rarely bite, even when threatened - not that I’d advocate you approaching one! - but as they must hunt fish that are faster than them in the water, their venom is potent enough to immediately immobilize and kill even their largest prey.

Transactions of the scientific meetings of the Zoological Society of London. 1841.

Dyspholidus typus - The Boomslang Though it belongs to the same family as king snakes and the most common “grass snakes”, the boomslang is one of the few members of Colubridae to possess a venom that’s legitimately dangerous to humans, and the fangs that are able to inject it (some members of the family have venom, but weak fangs). In fact, the fangs of the boomslang are some of the broadest and most deeply-grooved in the snake world. The venom of the boomslang is hemotoxic. That means that the proteins in the venom affect the blood of the victim, and in the case of the most common hemotoxin in boomslang venom (phospholipase A2, if you’re wondering), it causes red blood cells to rupture. Given enough time with this toxin floating around in the bloodstream, the significant thinning of the blood allows it to flow out of the capillary walls, and can flow out of any part of the body where capillaries are particularly close to the exposed surface. In other words, if you’re bitten by a boomslang and don’t seek help right after being bitten, you’ll likely end up bleeding out from your nose, eyes, mouth, ears, and genital orifices. Because of the significant blood loss associated with a wait of more than 48 hours between bite and antivenin administration (phospholipases are fairly slow-working, compared to neurotoxins and cardiotoxins), full blood transfusions are sometimes needed, to replenish the plasma, red blood cells, and platelets that were lost in the bleed-out. Illustrations of the Zoology of South Africa. Andrew Smith, 1888.

Dyspholidus typus - The Boomslang

Though it belongs to the same family as king snakes and the most common “grass snakes”, the boomslang is one of the few members of Colubridae to possess a venom that’s legitimately dangerous to humans, and the fangs that are able to inject it (some members of the family have venom, but weak fangs). In fact, the fangs of the boomslang are some of the broadest and most deeply-grooved in the snake world.

The venom of the boomslang is hemotoxic. That means that the proteins in the venom affect the blood of the victim, and in the case of the most common hemotoxin in boomslang venom (phospholipase A2, if you’re wondering), it causes red blood cells to rupture. Given enough time with this toxin floating around in the bloodstream, the significant thinning of the blood allows it to flow out of the capillary walls, and can flow out of any part of the body where capillaries are particularly close to the exposed surface.

In other words, if you’re bitten by a boomslang and don’t seek help right after being bitten, you’ll likely end up bleeding out from your nose, eyes, mouth, ears, and genital orifices. Because of the significant blood loss associated with a wait of more than 48 hours between bite and antivenin administration (phospholipases are fairly slow-working, compared to neurotoxins and cardiotoxins), full blood transfusions are sometimes needed, to replenish the plasma, red blood cells, and platelets that were lost in the bleed-out.

Illustrations of the Zoology of South Africa. Andrew Smith, 1888.

biomedicalephemera: Bothrops jararaca - Jararaca or Yararaca This is just one of the many pit vipers that inhabit South America. It is currently particularly prevalent in Argentina and Paraguay, though it was historically mostly found in Brazil - this may be a result of more people living in the Paraguayan and Argentinian territories than Brazilian, however.  This is a significant species of pit viper primarily for its venom being the source of several base peptides used in ACE inhibitors, used for congestive heart failure cases. Though its bites cause death only ~1% of the time, these snakes are considered dangerous as they are very prevalent, and cause death years after the bite more frequently than other snakes. Their hemotoxic venom affects the heart and vessels in such a way that they are sometimes unable to deal with the stresses of aging. Bilder-atlas zur wissenschaftlich popularen. Leopold Fitzinger, 1867. Here’s a real jararaca! :D

biomedicalephemera:

Bothrops jararaca - Jararaca or Yararaca

This is just one of the many pit vipers that inhabit South America. It is currently particularly prevalent in Argentina and Paraguay, though it was historically mostly found in Brazil - this may be a result of more people living in the Paraguayan and Argentinian territories than Brazilian, however. 

This is a significant species of pit viper primarily for its venom being the source of several base peptides used in ACE inhibitors, used for congestive heart failure cases. Though its bites cause death only ~1% of the time, these snakes are considered dangerous as they are very prevalent, and cause death years after the bite more frequently than other snakes. Their hemotoxic venom affects the heart and vessels in such a way that they are sometimes unable to deal with the stresses of aging.

Bilder-atlas zur wissenschaftlich popularen. Leopold Fitzinger, 1867.

Here’s a real jararaca! :D

biomedicalephemera: Method of the mussurana’s attack upon the jararaca. Note the size difference between the two snakes. The mussurana is able to consume comparatively large snakes because its digestive system compresses the body of the other snake into a wave-like shape. Through the Brazilian Wilderness. Theodore Roosevelt, 1914. Here’s a jararaca! I’m still gonna find that other one, whether it wants to be found or not…

biomedicalephemera:

Method of the mussurana’s attack upon the jararaca.

Note the size difference between the two snakes. The mussurana is able to consume comparatively large snakes because its digestive system compresses the body of the other snake into a wave-like shape.

Through the Brazilian Wilderness. Theodore Roosevelt, 1914.

Here’s a jararaca! I’m still gonna find that other one, whether it wants to be found or not…

biomedicalephemera

Bothrops jararaca - Jararaca or Yararaca This is just one of the many pit vipers that inhabit South America. It is currently particularly prevalent in Argentina and Paraguay, though it was historically mostly found in Brazil - this may be a result of more people living in the Paraguayan and Argentinian territories than Brazilian, however.  This is a significant species of pit viper primarily for its venom being the source of several base peptides used in ACE inhibitors, used for congestive heart failure cases. Though its bites cause death only ~1% of the time, these snakes are considered dangerous as they are very prevalent, and cause death years after the bite more frequently than other snakes. Their hemotoxic venom affects the heart and vessels in such a way that they are sometimes unable to deal with the stresses of aging. Bilder-atlas zur wissenschaftlich popularen. Leopold Fitzinger, 1867.

Bothrops jararaca - Jararaca or Yararaca

This is just one of the many pit vipers that inhabit South America. It is currently particularly prevalent in Argentina and Paraguay, though it was historically mostly found in Brazil - this may be a result of more people living in the Paraguayan and Argentinian territories than Brazilian, however. 

This is a significant species of pit viper primarily for its venom being the source of several base peptides used in ACE inhibitors, used for congestive heart failure cases. Though its bites cause death only ~1% of the time, these snakes are considered dangerous as they are very prevalent, and cause death years after the bite more frequently than other snakes. Their hemotoxic venom affects the heart and vessels in such a way that they are sometimes unable to deal with the stresses of aging.

Bilder-atlas zur wissenschaftlich popularen. Leopold Fitzinger, 1867.

rhamphotheca: Illustration of a Spectacled Caiman (Caiman crocodilus) and a False Coral Snake (Anilius scytale) by Maria Sibylla Merian (1647–1717)

rhamphotheca:

Illustration of a Spectacled Caiman (Caiman crocodilus) and a False Coral Snake (Anilius scytale)

by Maria Sibylla Merian (1647–1717)

rhamphotheca

Bitis nasicornis - The Rhinoceros Viper or River Jack The river jack is also known as the horned puff adder, though the latter name is given to more than one “horned” viper. It’s native to the central African forests, and is rarely seen outside of heavily forested and humid areas.  As a viper, the river jack has a highly venomous bite, and limited studies suggest that it’s very near (if not) the most venomous puff adder. It’s not a highly aggressive species, but has known to defend its territory more than the more well-known Gaboon Viper. Given the more hemotoxic venom and the more defensive demeanor, this viper could well account for many deaths per year, but Central African snake bites are often unreported and untreated. Noviates Zoologicae: A Journal of Zoology. Vol X. The Hon. Walter Rothschild & Dr. Ernst Hartert, 1903.

Bitis nasicornis - The Rhinoceros Viper or River Jack

The river jack is also known as the horned puff adder, though the latter name is given to more than one “horned” viper. It’s native to the central African forests, and is rarely seen outside of heavily forested and humid areas. 

As a viper, the river jack has a highly venomous bite, and limited studies suggest that it’s very near (if not) the most venomous puff adder. It’s not a highly aggressive species, but has known to defend its territory more than the more well-known Gaboon Viper. Given the more hemotoxic venom and the more defensive demeanor, this viper could well account for many deaths per year, but Central African snake bites are often unreported and untreated.

Noviates Zoologicae: A Journal of Zoology. Vol X. The Hon. Walter Rothschild & Dr. Ernst Hartert, 1903.

defrag: Ophidia I. Tropidonotus natrix : guildofscientifictroubadours.com

defrag:

Ophidia I. Tropidonotus natrix

: guildofscientifictroubadours.com