Foals are young ponies, depicted at various ages on the show, from babies to teenagers. Exact ages are not specified, but there is a clear distinction between babies, school-age ponies, and adult ponies.
Cheerilee refers to the Cutie Mark Crusaders and their classmates as "my little ponies" in The Show Stoppers, Call of the Cutie, The Return of Harmony Part 1, and The Cutie Pox. The term is also used by Princess Celestia and Discord for the main cast, by Granny Smith for Cheerilee's class, by Pinkie Pie for the competitors of the Running of the Leaves, and by Twilight Sparkle for the Cutie Mark Crusaders in The Show Stoppers.Foals on the show are smaller than adult ponies, their heads are proportionately larger, their limbs are shorter, and their eyes are more circular as opposed to the elliptical eyes of the adults. Unlike previous My Little Pony generations, not all younger ponies are called "baby ponies". Child ponies, such as Apple Bloom or Sweetie Belle, aren't referred to as babies, but rather as "fillies". This is the term for females, with the equivalent male term being "colts", which has only been used in The Show Stoppers, Baby Cakes, both parts of A Canterlot Wedding, Pinkie Pride, Appleoosa's Most Wanted, The One Where Pinkie Pie Knows, The Cutie Re-Mark - Part 1, Top Bolt, The Perfect Pear, A Health of Information, Surf and/or Turf, The End in Friend, A Rockhoof and a Hard Place, and School Raze - Part 1. The younger versions of the leading characters are simply referred to as "young" or "fillies". The term "foals" is used by Nightmare Moon in a different context, as a play on the phrase "step back, you fools". It is used again in the same context in the Hearth's Warming Eve play. The term is used to refer to young ponies in Over a Barrel and Baby Cakes.
The difference between baby ponies and young ponies is accented in the episode Call of the Cutie. School teacher Cheerilee shows a picture of herself at a very young age, and later contrasts it with another picture of herself being somewhat older than her students. She is depicted not possessing a cutie mark in the former picture, and remarks that "her flank was blank" until she grew older and got her cutie mark when she found her talent as a teacher and to help her students bloom with knowledge.
Most of the named colts on the show have unique character designs, unlike the fillies, stallions, and mares, who almost always share the same body design.
Plaid Stripes, "Pearly Whites", "Thunderstruck", filly Fluttershy, later filly Applejack, later filly Derpy, later filly Pear Butter, and Crystal Hoof have a more mature design than other foals, seen with a big head and skinny legs.
Most of the youngest of baby ponies have eyes that are styled differently from the usual pony eyes, more closely resembling the bead-like eyes with giant eyelashes of the pets from Hasbro's toy line. Cream Puff and Pound Cake and Pumpkin Cake share this design, which is also used by Apple Bloom when shown as a baby in photos in Ponyville Confidential, Snips and Snails when turned into babies in Magic Duel, Applejack and another pony when shown as babies in a flashback and/or photos in Apple Family Reunion, and yet another pony when shown as a baby in a flashback in Top Bolt. Other babies with the same design appear in Baby Cakes and various other materials. In The One Where Pinkie Pie Knows, baby Applejack's design is updated to include normal-looking eyes. This same design is used for Flurry Heart.
- Main article: Cutie marks
During Call of the Cutie, Cheerilee tells her students that no amount of pleading, wishing, or begging will make a cutie mark happen before its time, and that the best thing to do is wait. Different ponies develop different special talents as they mature, and at different times; for instance, Rarity's special skill is gem-finding, Fluttershy's is caring for animals, Rainbow Dash's is speed, Applejack's is apple farming, and Pinkie Pie's is party-throwing.
One prominent example of a pony finding her talent is Twilight Sparkle. During a flashback in The Cutie Mark Chronicles, she studies hard at magic and her parents enroll her in Celestia's School for Gifted Unicorns. The sonic rainboom spurs her powerful magic into action, showing that she has enough raw magic ability to turn her parents into foliage and enlarge an infant Spike. Princess Celestia informs Twilight that she's never seen that much raw talent in a unicorn before, and her cutie mark subsequently appears.