When you are born with a shell on your back, making sure your large shell-less assistant knows precisely which species you are can be pretty important.
Unfortunately, your taxonomony (what the shell-less beings call your rank, file and serial number, aka your classification) doesn’t exactly make this easy.
Technically, all shelled beings are “turtles.”
Yet some of these turtles live nearly full-time in fresh water or salt water or part-fresh/part-salty (brackish) water, some live partly in water and partly on land and some live nearly full-time on land.
For these and other reasons, some shelled beings are called “turtles.” Others are called “terrapins.” Still others are called “tortoises.”
For general purposes, the “turtles” and “terrapins” are the ones who like to live in water (fresh, salt or half-and-half) most of the time…except for “box turtles,” which prefer to live on land like tortoises.
And all of them – turtles, terrapins and tortoises – come to the land to lay eggs.
This means that all baby shells start out in life on land, although many of them (especially sea turtles) will then hightail it into the water as fast as they can.
If you look at a turtle versus a tortoise, it is often possible to tell them apart just by what they look like. This is because they are built with their preferred habitat in mind.
If you are a turtle or a terrapin who spends at least half your time in water (box turtles excepting), you won’t want to be too heavy or you will sink. Also, you will want to have feet that are more like flippers to make you good at swimming and navigating through water.
Even box turtles can be sort of good swimmers – Bruce enjoys a good swim in a shallow pond as much as the next turtle, although he certainly isn’t built to live there!

If you are a tortoise who prefers to live on land, you are going to want to carry more armor around with you to make you look very tough and inedible.
And you will want to make sure you have broad, sturdy feet with thick skin that can repel pests and predators alike.

As you might imagine, it only gets more complicated from here and we won’t even go into what turtles, terrapins and tortoises like to eat, how they like to spend the cold season, their humidity and warmth needs, why they seek out water (or land) and what they do once they’ve found it….
