We Love Snakes – Part 2: top 5 reasons snakes are fascinating
My goal when I sat down to write today’s blog was to highlight a few interesting facts about snakes. This turned out to be a bit more of a challenge than I expected because there are just so many that it is hard to decide which ones to write about! After much internal debate, here are my top 5 reasons why snakes are fascinating:
- 1. Snakes have been incredibly successful. They may be found on every continent except Antarctica. They live in most ecosystems including the ocean. There are snakes that live underground and snakes that live in the tops of trees. Some snakes never leave the water while others live in the driest of deserts. They range in size from a few inches to more than 20 feet in length. One group of snakes in Southeast Asia can even flatten their bodies and glide from tree to tree. Amazingly, this success is at least partially the result of snakes losing their limbs!
- 2. Snakes can swallow something bigger than their head. Their lower jaws are only loosely attached to their skull and the left and right side jaw bones are only connected to each other by a flexible ligament. This allows snakes to stretch their mouths open to an amazing extent and explains how a skinny snake can swallow fatter prey including rats and mice that spread disease and destroy crops. Snakes are not only important to the ecosystems they live in, but are extremely beneficial to humans.
- 3. Snakes are gorgeous. There are striped snakes, banded snakes, checked snakes, two-toned snakes, red snakes, blue snakes…the diversity of appearance is incredible. They are all beautiful, and many are absolutely stunning. Check out a picture of a tangerine phase Honduran milk snake or the aptly named emerald tree boa and you will see what I mean!
- 4. Snakes have very interesting eyes. Most reptiles, birds and mammals focus by altering the shape of the flexible lens in their eyes. But the lens in a snake’s eye is rigid; so instead snakes focus their eyes by moving them forwards and backwards (like a camera). For a long time this was cited as evidence that snakes originally evolved to live underground. Eyes aren’t much value in that environment, so the explanation was that their eyes degenerated and then had to re-develop when snakes moved back to the surface. This idea was supported by the fact that many primitive snakes live underground and only have vestigial eyes. However, recent research shows that the eyes of snakes are very similar to many aquatic vertebrates. This, plus fossils of aquatic snakes that still had hind legs suggests that snakes may have originally evolved to live in water and then afterwards adapted to life on land.
- 5. Some snakes are venomous. Many species of snakes produce venom, and some are extremely dangerous. Unfortunately this not only makes them fascinating, it is also the prime reason that snakes are feared and hated. Snake venom is a complex cocktail of proteins, enzymes, polypeptides and other compounds that function to immobilize, and in some cases, start the digestion of their prey. The components of snake venom may disrupt blood coagulation, blood pressure regulation and nerve transmission. Needless to say, snake venom can also be a great deterrent to predators.
Elaphe hohenackeri, Transcaucasian Ratsnake or Taurus Mountain Ratsnake, close-up. Al-Shouf Cedars Reserve, Lebanon. © Michel Gunther / WWF-Canon
Note that in the last bullet above, I referred to some snakes being venomous, not poisonous. There is actually no such thing as a poisonous snake. The word poisonous refers to something that is dangerous to ingest because it contains a toxic substance. Some mushrooms and poison dart frogs are good examples. A venomous organism injects toxin (venom) into another animal using fangs, a sting, or some other specifically adapted structure. Well known examples of venomous animals are scorpions, lionfish, some species of snakes, and of course male duckbill platypuses.
But snakes aren’t poisonous. You can safely eat a snake and snake meat is a common food item in many parts of the world. Over-hunting for meat is one of the threats to the conservation of snakes that I will be writing about in Part 3 of this series. Stay tuned…