Out There: Creston Valley snakes eat frogs — as well as dust

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Ed McMackin is a biologist by profession but a naturalist and hiker by nature.

Ed McMackin is a biologist by profession but a naturalist and hiker by nature.

What do garter snakes eat? Most of you would say they eat frogs. Quite right! It’s quite a little feat to swallow a frog. It is even more of a feat if the frog, like a bullfrog, is apt to swallow the snake. If the snake can’t eat the frog, perhaps the frog can eat the snake. Snakes are equipped to swallow frogs and other little critters that appear even a little larger than what we think they could swallow. In swallowing, they do a lot of stretching but they don’t do it without getting, not their nose out of joint, but their jaws separated to allow the throat to expand. Now the snake does get a big lump in the throat, which follows on along the digestive tract getting smaller as it is digested.

But a garter snake’s menu can include more than frogs. They feast on other amphibians, perhaps other snakes and lizards, on insects and their larva and fish. They also eat mice and voles and their young, and have some items on their list that we, perhaps, would not like to think of.

Once out on a trail I heard some hissing and other bird stress calls coming from a bush. There I found a song sparrow nervously flitting about the lower part of the bush, which contained a nest and young, making sounds that I would never expect from a sparrow. The object of the sparrow’s distress was a garter snake climbing up the trunk and limbs of the bush, already halfway to the nest. It gained “footholds” by using body compression friction and traction afforded by the belly scales. I didn’t see it reach the nest but assumed it was after the young birds. Snakes have a keen sense of smell and will, if given the opportunity, eat young and eggs of birds.

Like humans, mammals and birds, snakes smell with their nose but also “smell” with their tongues. They don’t strike with their tongue, which is harmless, but, often, frequently flick the tongue in and out, taking in dust from the air, from the ground and from nearby objects. This is how they eat dust. By licking and eating dust they can assess their environment through a sensory organ, known as the Jacobsen’s organ, located in the roof of the mouth.

I can remember, as a kid, crash-landing with my bike and getting a mouth full of grit and dust or getting dust in the face from a car passing on a dry, dusty road. Not very nice! Then there is the expression “bit the dust” which sometimes implies a mishap or end of story. Eating dust is not something that many people would choose.

Snakes do purposefully and deliberately bite, eat and taste dust. There’s truth in that biblical reference that says, “the serpent shall eat dust”. (Genesis 3:14, King James Version) This phrase has much symbolism but is also very real, as scientific studies have shown. In fact, the field of science, in recent years, has turned up more discoveries that make more sense out of some biblical topics than what some people would like to acknowledge, about snakes or about anything in the natural world.

Ed McMackin is a biologist by profession but a naturalist and hiker by nature. He can be reached at 250-866-5747.