where does a snake's body end and its tail begin?
We like to joke that snakes are just tails with faces, but the truth is that their bodies end and their tails start in about the same place as all vertebrates, including dogs and cats!
That's weird to think about, right?
Let's take a look with the help of Apollo II:
It's hard to see from the top, but Apollo II has a clear delineation of his body before, at, and after his pelvic region. I've color-coded it below so that you can hopefully see it a little easier.
Snakes don't have a pelvis per se, though older species like boids and pythons have vestigial pelvic structures. As a male, Apollo II has a more gradual taper from body to tail where a female would have a sharper delineation. It'll be easier to see the boundary between body and tail from underneath.
You'll notice that Apollo II's tummy scales nearer the front of his body are broad and solid with a single scale per row. These are called ventral scales. Then there's a large broad scale that's divided into two, the anal scales, and then after that his tummy scales are smaller and there are two per row. These are called subcaudal scales.
Remember when I said that snakes' bodies end and their tails start in about the same place as dogs and cats? Where does a cat's body end and their tail begin?
The anal scales, true to their name, cover his cloaca, which is the "anything goes" hole off the reptile world. Waste from his kidneys and intestine are passed from his body, and musk from his scent glands as well as his hemipenes are pushed up from the tail section. It all comes out through the cloaca, which is also known as the vent.
So as you now see, a snake's body ends and its tail begins, as with all vertebrates, at the booty.