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.

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.