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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.](http://24.media.tumblr.com/c04425d836f7d3531469b5ae504d6e7a/tumblr_mfpmfp0SSL1qk931ho1_500.jpg)
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]
Skeleton of the Chicken (Gallus gallus domesticus)
Superimposed over the basic form of the fowl, to give a better approximation of how the musculature and feathering of the animal is constructed.
The bird; its form and function. C. William Beebe, 1907.
(via biomedicalephemera)
Thornback ray (Raja clavata) and thornback ray skeleton
Like sharks, rays and skates have fully cartilaginous skeletons, which provide a stable structure but more flexibility than bone. You can see that, much like fish, rays have defined, er, rays, in their fins. The difference is that while fish tend to have a few unconnected rays and a taught tissue between them, the Rajiforms (skates and rays) have many, many rays, which are all connected perpendicularly by collagen. The body is then formed around these rays, which propel the Rajiforms forward in an undulating (wave-like) motion.
A history of the fishes of the British Islands. Jonathan Couch, 1863.
(via scientificillustration)
Thornback ray (Raja clavata) and thornback ray skeleton
Like sharks, rays and skates have fully cartilaginous skeletons, which provide a stable structure but more flexibility than bone. You can see that, much like fish, rays have defined, er, rays, in their fins. The difference is that while fish tend to have a few unconnected rays and a taught tissue between them, the Rajiforms (skates and rays) have many, many rays, which are all connected perpendicularly by collagen. The body is then formed around these rays, which propel the Rajiforms forward in an undulating (wave-like) motion.
A history of the fishes of the British Islands. Jonathan Couch, 1863.
Nine-Banded Armadillo (Dasypus novemcinctus)
Did you know that the nine-banded armadillo (and a few of its Dasypus cousins) gives birth to identical quadruplets in almost every litter? Shortly after the zygote implants in the uterus, it splits into four (or occasionally three or five) separate embryos, each of which develop their own independent placenta. This means that, unlike in identical human fetuses, blood and nutrients are not shared, and the death of one fetus is unlikely to affect the survival of the others. After the pups are born, they remain in the burrow for approximately three months, and over the next year of their life, slowly wander farther and farther away from their place of birth.
As nine-banded armadillos have few natural predators in their Northern range, this highly effective reproduction strategy means that one female will often produce upwards of 50+ offspring in her relatively short lifetime. Those offspring have been expanding the armadillo’s known range for the past several decades. However, as armadillos are poor at thermoregulation, they’ve just about reached the limit of the area that they can survive in - any farther north, and they would not be able to survive the longer winters.
Images:
Top: Tatusia novem cincta [now Dasypus novemcinctus] - The Nine-Banded Armadillo. From Biologia Centrali-Americana. F. Ducane Godman and Osbert Salvin, 1918.
Bottom: Fetal Nine-banded Armadillo Pups. The American Journal of Anatomy. Vol. III, 1900-1901. “Enamel in the teeth of an edantate.” A. M. Spurgin.
Limbs of the Cephalopoda
Whether squids, octopuses, and nautilus have “arms” or “tentacles” is often simply a matter of semantics, but the most accepted definitions (from what I’ve found) tend to define the “arm” as a tapered limb, with two rows of suckers along its entire length. “Tentacle” is typically a length of tapered limb with no suckers, leading to a distal club-like appendage, covered in suckers.
One exception would be limbs in the nautilus - they have up to 90 un-suckered limbs, but their limbs are called “tentacles” by those who study them, even without the terminal club.Images:
Top right: Octopus vulgaris and detail of beak and arms
Top left: Detail of tenticular clubs in squid, from the Expedition of the Valdivia
Bottom right: Arm of Illex illecebrosis (Northern Shortfin Squid)
Bottom left: Tentacle of Illex illecebrosis
Faces of Lorises
1. Nycticebus tardigradus malayanus (Nycticebus coucang spp.- Sunda slow loris. Note: possibly Nycticebus javanicus - the Javan slow loris)
2. Nycticebus tardigradus hilleri (Nycticebus coucang coucang - the Sunda slow loris, type species)
3. Loris gracilis typicus (Loris lydekkerianus lydekkerianus - Gray slender loris)
4. Loris gracilis zeylanicus (Loris tardigradus - Red slender loris)All lorises are endangered or vulnerable due to the pet trade and their use in traditional “medicine”. While these small and nocturnal critters tend to be much more adaptable when humans encroach upon their habitat than other species of primate (making due in the trees humans transplant as opposed to their native foliage, and dealing with the human presence in stride, for example), they’re still all too often thought to “cure” various ailments with their body parts (especially the slow lorises), and traded as pets throughout their native habitat of Southeast Asia, and when they’re successfully smuggled to the rest of the world.
Seriously, people. Their cuteness is so much cuter in the wild. Lorises are freaking adorable, and the hunting strategies of the various species and subspecies are so varied and fascinating that they deserve to stay in a protected natural habitat. I mean, among other reasons to preserve them, obviously…they’re just such cool little omnivores!
Proceedings of the Zoological Society of London, 1904.
The tongue of the woodpecker.
Woodpeckers have tongues almost as long compared to skull length as anteaters do. It’s very effective for scooping up bugs trying to escape your pecking beak!
The Hand; its Mechanism and Vital Endowments, as Evincing Design. Sir Charles Bell, 1854.
Lion Claw.
Lion paws have an extra joint compared to other cats, and this gives them extra range-of-motion. Thanks to this additional range, lions can sink their claws deeper into prey than any other mammal, and they can hang on through a huge amount thrashing and struggling. Their broad pads that allow for silent movement also provide a huge surface area to back up a swipe with the claws, and combined with the massive forebody muscling, this allows lions to deliver a blow strong enough to break a zebra’s back.
The Hand; its Mechanism and Vital Endowments, as Evincing Design. Sir Charles Bell, 1854.
