MUSEUM OF NATURE

Press, Volume CIX, Issue 31984, 10 May 1969, Page 5

MUSEUM OF NATURE

Hyrax—The Extreme In Evolution

(Contributed by the ; Canterbury Museum) , Tucked away in a ‘ small case in the Hall of Biology at the Canterbury Museum is a j small animat—the rock i hyrax commonly known 1 as Dassie. It is a' curious quirk of ’ nature that the greatest of ail . land animals, weighing J several tons, and sometimes 1 standing neairty 12ft at the ’ shoulder/ should have as its 1 nearest relative this little creature no bigger than a rab- 1 bit; yet apologists, after study- ' ing the anatomy of the ele- ' phant and comparing it with ; that of the’ hyrax or rock , rabbit, are agreed that this is most certainly the case. ' In outward appearance it • would be hard to find two 1 animals so extremely dissimi- ■ lar, for in addition to the disparity in size, there is no ■ single external feature which gives a clue to the relationship, and it is only by careful comparison of the skeletal structure of the feet that kin- ■ ship between the two creatures can be established. Kinship dates far back into geological time when the elei phant as we know it did not . exist, nor had its then living , ancestor developed anything resembling a trunk. From : fossil remains we suppose it , to have been a rather clumsy [ animal, somewhat tapir-like . in appearance and size with ■ i only the barest suggestion of ; a proboscis. It is at this l point that we get the first r evidence of relationship. This > creature,-which is known to .scientists astiie Moerither- . ium, was descended from the - same line of ancestors as were the progenitors of the hyrax. Change In Bulk Next in the-ancestry of the elephant came a beast, called ■ the Palaeomastodon which - was the first of the elephants • to own the beginnings of a ■ trunk. From the Palaeo- > mastodon the succession of l. links has been traced to the ■ Mastodon and the Mammoth, • whose remains have been > found in Siberia. E While in the course of evol lution the elephant has 5 increased in bulk, the hyrax ■ appears to have decreased s in almost the same proportions for it had as one of its

ancestors the Megalohyrax, which was a contemporary and about the same size as the Moeritherium. Both groups originated in Africa, but whereas the elephant wandered over the greater part of the earth, secure in its massive strength, the hyraxes hardly ever strayed from home and no remains of it have been found further afield than Greece. Different habits became evolved and on the one hand we have a story of increasing size and strength, while on the other we have an animal of furtive, cringing habit, ever decreasing in courage and size till it reached its present state. The hyrax, therefore, in comparison with the elephant provides the extremes to which evolution may go. Similar To Rabbit In external appearance, form and colour, the hyrax is not unlike the rabbit with a somewhat rat-like head. Indeed at one time they were included among the rodents, because of its size and because their front teeth are somewhat similar to those of the rodents. It has no canine teeth, while its molars resemble those of a rhinoceros in both form and number. There is no tail and it does not hop like a rabbit but walks or runs, using its legs separately. The forelegs are shorter than the hindlegs, giving the animal the appearance of being low in front This is accentuated by a bushy collar of hair round the throat. Hyraxes have four toes on the front limbs and three on the back limbs; the soles of the feet are covered with firm pads which arc used in obtaining a good grip on trees and rocks. The toes all have hoof-like nails, except the second toe on each hind foot which has a curved claw, and is used as a “toilet digit” Hyraxes climb with great agility up the perpendicular sides of rocks,’ and they are also remarkable jumpers, thinking nothing of jumping down from a height of 10 to 15 feet From perpendicular or even overhanging cliff faces 24 to 30 feet high they come down like a cat, sliding or running threequarters of the way before taking off with all four legs and landing elegantly on the ground.

Hyraxes generally live in flocks or colonies of 50 to 60, in the hollows and caves of rocks on the hillsides and down on the seashore just above the high water mark. They are extremely timid and shy in the wild state, although in captivity become tame and some species even become aggressive to strangers. Because of their agility they are rarely caught alive. They are entirely herbivorous and their flesh tastes like rabbit.

In the Bible, the Israelites were forbidden to eat the flesh and in this they were probably wise, for the alimentary canal usually contains a heavy load of tapeworms and roundworms.

“And the coney (hyrax), because he cheweth the cud, but divideth not the hoof he is unclean upto you”—Leviticus XI. The passage is not, however, correct from the zoological point of view, for in fact the hyraxes do not chew the cud. It is possible that the characteristic twitching movement of the hyraxes was interpreted as a form of cud chewing. The specimen on display in the Canterbury Museum is the Cape Rock rabbit (Procavia capensis) or rock hyrax, of which seven species are distributed over Africa and the Near East. This includes the Syrian hyrax (Procavia syriacus), referred to jn the Bible as the coney. There are also three species of tree hyraxes found in Africa only.—J.H.J.