Most relatives and close friends quickly learn to tell twins apart. Physical differences may include:
- Height One is taller and one is shorter.
- Build One is thinner and one is chubbier.
- Physical characteristics One has a rounder face and one has a longer face, one twin has freckles or a mole that the other one doesn't have, or their ears may be different shapes.
- Voices Their voices are different. (This is even true of babies' cries.)[source: lilsugar]
Some identical twins are mirror images of each other. Knowing this (especially if one is right-handed and one is a lefty) can help you tell them apart.
Sometimes there are habits that can help you tell twins apart. For example, one might bite his nails. Look out for small things that differentiate them.
Twins often differ in personality. Some ways you can tell them apart based on their personalities are:
- One twin is more "smiley" while the other tends to scowl.
- One is outgoing and the other is shy.
- One is a morning person and one is a night owl.
You may be able to tell twins apart by their interests. For example, one might be into sports while the other is a bookworm.
What about when your twins are just born and their personalities haven't developed yet? Here are some things you can do so you don't mix up your newborn twins before you learn to tell them apart:
- Leave their hospital bracelets on until you're comfortable telling them apart. You can also buy them ID bracelets or anklets.
- Dress the babies in assigned colors. Color-code their bedding (so you put them in the right cribs) and their eating and sleeping charts if you use them [source: Whiteley].
- Paint one toenail on each baby (in their assigned colors). Don't paint a fingernail in case they suck their fingers.
- Put nametags on their shirts.