272 



NATURE 



[July 



1903 



It may be mentioned that the Exmoor pony had, in 

 1900, and again in 1901, a zebra hybrid, the sire being 

 the Burchell zebra " Matopo," used in my telegony 

 experiments. In the case of her Kiang hybrid the 

 period of gestation was 335 days (one day short of 

 what is regarded as the normal time), but she carried 

 her 1900 zebra hybrid 357 days, three weeks beyond the 

 normal time. The Exmoor-zebra hybrids are as nearly 

 as possible intermediate between a zebra and a pony ; 

 the Kiang hybrid, on the other hand, might almost 

 pass for a pure-bred wild ass.^ In zebra hybrids the 

 ground colour has invariably been darker than in the 

 zebra parent ; but the Kiang hybrid is decidedly lighter 

 in colour than her wild sire, while in make she 

 strongly suggests an Onager — the wild ass so often 

 associated with the Runn of Cutch. Alike in make 

 and colour, the Kiang hybrid differs from a young 

 Przewalsky foal.^ 



I have never seen a new-born wild horse, but if one 

 may judge from the conformation of the hocks, from 

 the coarse legs, big joints, and large heads of the 



withers until 



Sire of Hybrid. 



yearlings — from their close resemblance to dwarf cart- 

 horse foals — it may be assumed they are neither 

 characterised by unusual agility nor fleetness. The 

 Kiang hybrid, on the other hand, looks as if built 

 for speed, and almost from the moment of its birth 

 it has, by its energy and vivacity, been a source of 

 considerable anxiety to its by no means placid Exmoor 

 dam. When four days old it walked more than twenty 

 miles ; on the fifth day, instead of resting, it was 

 unusually active, as if anxious to make up for the 

 forced idleness of the previous evening. In the hybrid 

 the joints are small, and the legs are long and slender 

 and covered with short closeTlying hair. In the wild 

 horse the joints are large, and the " bone " is round 

 as in heavy horses. 



As to its colour, it may be especially mentioned that 



1 The wild parent is generally prepotent over the tame — in Mendelian 

 terms the Kiang proved dominant, the Exmoor pony recessive. 



2 For a .skin of a very young Przewalsky foal I am indebted to Mr. Carl 

 Hagenbeck, of Hamburg. 



the hybrid has. more white around the eyes than the 

 w'xXA horse, but is of a darker tint along the back and 

 sides and over the hind quarters. Too much import- 

 ance, however, should not be attached to differences in 

 colour, for, though the two hybrid foals which have 

 already arrived closely agree in their coloration, sub- 

 sequent foals may differ considerably, and it is well 

 known that young wild horses from 'the western por- 

 tions of the Great Altai Mountains differ in tint from 

 those found further east. 



Of more importance than the coat-colour is the 

 nature of the hair. A Przewalsky foal has a woolly coat 

 not unlike that of an Iceland foal. In the hvbrid, the 

 hair IS short and fine, and onlv slightly wavy over the 

 hmd quarters. It thus differs but little from a 

 thoroughbred or Arab foal. 



The mane and tail of the hybrid are exactly what 

 one would expect in a mule; the dorsal band, 75mm. 

 wide over the croup in the sire, has in the hybrid a 

 nearly uniform width of 12mm. from its origin at the 

 t loses itself half-way down the tail. 

 The tail, which differs but little from 

 that of a pony foal, is of a lighter 

 brown colour than the short upright 

 mane, while the dorsal band is of a 

 reddish-brown hue. In the wild 

 horse the dorsal band is sometimes 

 very narrow (under 5mm.) and in- 

 distinct. In the Kiang sire there are 

 pale but quite distinct stripes above 

 and below the hocks, and small faint 

 spots over the hind quarters — vestiges, 

 apparently, of ancestral markings ; 

 but in the hybrid there are neither in- 

 dications of stripes across the hocks 

 or withers, nor spots on the quarters.^ 

 In having no indications of bars on 

 the legs or faint stripes across the 

 shoulders, the hybrid differs from 

 Przewalsky colts ; it also differs in 

 having a longer flank feather, and in 

 the facial whorl being well below the 

 level of the eyes. As in the Kiang 

 and wild horse, the under surface of 

 the body and the inner aspect of the 

 limbs are nearly white. 



In the hybrid the front chestnuts 

 (wrist callosities) are smooth and just 

 above the level of the skin, but in- 

 stead of being roughly pear-shaped as 

 in the Kiang, they are somewhat 

 shield-shaped, as in the Onager, In 

 the wild horse the front chestnuts are 

 elongated. 

 In the Exmoor dam the hind chestnuts (hock callosi- 

 ties) are 27mm. in length and lomm. wide. In the 

 sire there is a minute callosity inside the right hock. 

 In the hybrid the hind chestnuts are completely absent. 

 In the absence of hock callosities the hybrid differs 

 from the wild horse, in which they are relatively longer 

 than in Clydesdales, Shires, and other heavy breeds 

 of horses. In the hybrid, as in the sire and dam, there 

 are smooth, rounded fetlock callosities (ergots) on 

 both fore and hind limbs. 



In the wild horse the Koof is highly specialised, the 

 " heels " being bent inwards (contracted) to take a 

 vice-like grip of the frog. In the hybrid the hoof 

 closely resembles that of the pony dam ; it is shorter 

 than in the Kiang, and less contracted at the " heels " 

 than in the wild horse. 



The Kiang hybrid further differs from a young wild 



1 The complete absence of stripes in the Kiang hybrid is all the more 

 interesting, seeing that the dam's previous foals were zebra hybrids. 

 Evidently the Kiang hybrid lends no support to the telegony doctrine. 



uin-lVihnot. 



NO. 1760, VOL. 68] 



