oldbookillustrations:

1) Morelia spilota (carpet python) 2) Oxyrhopus petolarius (forest flame snake)

From  Herrn de la Cepede’s Naturgeschichte der Amphibien (Mr de Lacépède’s Natural History of amphibians)  vol. 4, by Comte de Lacépède, Weimar, 1800.

(Source: archive.org)

oldbookillustrations:

1) Morelia spilota (carpet python) 2) Oxyrhopus petolarius (forest flame snake)

From Herrn de la Cepede’s Naturgeschichte der Amphibien (Mr de Lacépède’s Natural History of amphibians) vol. 4, by Comte de Lacépède, Weimar, 1800.

(Source: archive.org)

headlikeanorange:

Formentera wall lizard (Day’s Edge Productions)

headlikeanorange:

Formentera wall lizard (Day’s Edge Productions)

oldbookillustrations:

Third night, Third fable. Biancabella and the serpent.

Edward Robert Hughes, from The Nights of Straparola, by  Giovanni Francesco Straparola, London, 1894.

(Source: archive.org)

oldbookillustrations:

Third night, Third fable. Biancabella and the serpent.

Edward Robert Hughes, from The Nights of Straparola, by Giovanni Francesco Straparola, London, 1894.

(Source: archive.org)

biomedicalephemera:

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]

biomedicalephemera:

“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:

“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.

rhamphotheca:

American Alligator, Florida, USA
photo by Medford Taylor
American alligators like the one pictured here in the Florida Everglades have bounced back from the brink of extinction to thrive in their native habitat: the swamps and wetlands of the southeastern United States.
(via: National Geo)

rhamphotheca:

American Alligator, Florida, USA

photo by Medford Taylor

American alligators like the one pictured here in the Florida Everglades have bounced back from the brink of extinction to thrive in their native habitat: the swamps and wetlands of the southeastern United States.

(via: National Geo)

(via srta-kubelik)