Although wild horses were abundant after the last ice age, the lack of sufficient pre-domestication DNA samples makes it impossible to determine the contribution of the wild horses of the British Islands to modern breeds, including the Exmoor pony. A 1995 study of morphological characteristics, the outward appearance of organisms, indicated that the Exmoor, the Pottock, and the now-extinct Tarpan have an extremely close resemblance; these breeds were consistently grouped together in the results from several analyses, with the Exmoor showing the closest relationship to the Tarpan of all the breeds studied, at 0.27; the next-closest breeds to the Tarpan were the Pottock and Merens, both with a genetic distance from the Tarpan of 0.47. The distance between the Exmoor and Pottock was 0.37, and between the Exmoor and Merens was 0.40; a significantly wider gap than the distance between the Exmoor and Tarpan.