Assateague Island’s Newest Foal

Assateague Island ponies

Here’s N2BHS-M when she was a few months old.

One new foal was born this year to the Assateague Island ponies—and she needs a name!

Right now the filly is known as N2BHS-M. She was foaled in the area of the Assateague Island State Park campground on Memorial Day.

Assateague campground

Unexpected campsite visitors!


Why is she referred to as N2BHS-M? Well, back in the 1970s, the National Park Service began naming new foals in the Assateague herd with an alphanumeric code. This code helps track the maternal ancestry of each individual pony. (Maternal ancestry refers to the mother’s family line.)


Math Talk: Alphanumeric refers to a combined set of letters of the alphabet and the numbers 0 through 9.

The system is named after researcher Dr. Ronald Keiper, and is now known as “Keiper numbers”.

Here’s how it works: at birth, each pony is assigned a Keiper number created by adding the letter for its birth year to its mother’s Keiper number. Birth years began in 1976 with A, B for foals born in 1977, C for 1978, up through Z in 2001. At that point the alphabet was started over with a dash in front of the letter, resulting in -A for foals born in 2002.

Below is a chart showing the letter designation for each year.

Keiper number chart

The new foal’s dam is named Carol’s Girl and her Keiper number is N2BHS. Both mother and daughter are members of Yankee’s band. Yankee is one of the stallions on the island.

Horse Talk – dam: a horse’s female parent.
Assateague Island ponies

N2BHS-M and her dam Carols Girl

Using the chart above, trace the new foal’s maternal ancestry.

1. Which letter in the new foal’s Keiper number, N2BHS-M, indicates the year she was born?

2. Her dam, Carol’s Girl, has the Keiper number N2BHS. In what year was she born?

3. How old is Carol’s Girl?

4. What is the Keiper number for Carol’s Girl’s mother?

5. In what year was Carol’s Girl’s mother born?

6. What letter in Carol’s Girl’s Keiper number represents the year her granddam was born?

Now—what is the meaning of the first letter and number in each Keiper number?

In 1975, when the system was first introduced there were only 44 horses in three harem bands living on the Maryland portion of Assateague Island.

Horse Talk: A harem band consists of a dominant stallion and his mares and immature offspring.

Each of these bands was designated by the letter M, N or T.  The dominant stallion of each band was given the number 1, resulting in Keiper numbers M1, N1 and T1 for the stallions.  The other horses in each band were numbered consecutively beginning with 2 (M2, M3, N2, N3, T2, etc.).

Assateague Island ponies

Here’s N2BHS-M, less than a day old!

7. In the new foal’s maternal ancestry, what is the Keiper number for the first mare numbered back in 1975?

As mentioned above, in 2002, the alphabet began repeating itself again, this time with a dash in front of each letter.

8. In what year will the alphabet begin repeating itself again?

The Assateague Island Alliance, a group that works to protect the island and its ponies, holds various contests and auctions to raise money for their work.

One of their fundraisers is an upcoming name the new foal contest! They’ve scheduled a Name That Foal auction through eBay starting December 5, 2014. The winning bidder gets to name N2BHS-M!

9. Write this date using metric notation.

The bidding starts at $300. Last year, the winning bid was over $3,000.

10. If this year’s winning bid goes to $3,000, how much above the starting bid will the price have increased for the right to name N2BHS-M?

Click here to read another post about the Assateague ponies!

Common Core:
4.OA.A – Use the four operations with whole numbers to solve problems.
5.OA.B Analyze patterns and relationships.

All photos of Carol’s Girl and N2BHS-M are courtesy of the National Park Service
Assateague Island campground – 20100825-JAP_0535 by Jim Pennucci; CC BY 2.0

Tags: , , ,

2 Responses to “Assateague Island’s Newest Foal”

  1. Alexandra
    December 3, 2014 at 10:30 am #

    She’s soooooooooo cute 😀

  2. Samantha
    August 3, 2015 at 2:05 pm #

    Call her misty or stormy like the old movie I would really like that 🙂

Leave a Reply