An exclusive article for The Greatest Minds by biologist
Victoria Neblik in Jerusalem.
We head East, out of Jerusalem, past the cream stone tower-blocks and roadside beds of red and white roses and down the gentle slopes of the Judean mountains. Scattered olive trees and banks of pointed cypresses flash by the car windows. Gradually, the lushly irrigated landscape becomes more arid as we head towards the North Eastern tip of the Judean desert. Tree-flecked hillsides are replaced by barren, buff-coloured sand dunes and rounded hills with clear lines of rock strata across them. The weather forecast was for cool weather, which can only be a good thing in this part of the world, where summer temperatures regularly top 40°C.
As we travel away from Jerusalem, we are also traveling ever downwards; passing a smattering of roadside shops, cafés and the odd parked camel, we arrive at signs notifying us of sea level and then of being first 150m below it and then 300m below it. Our destination, the Ein Gedi wildlife reserve, stands virtually on the shores of the Dead Sea, which is the lowest point on Earth and, frequently, one of the hottest. Described by The Rough Guide to the area as “an oasis of (fresh) water and lush tropical vegetation”, on the edge of the Judean desert, the Ein Gedi reserve is famous for both its flora and its fauna. Rarest amongst these is a tree called Maerua crassifolia, but it is also said that hyaenas and up to thirteen leopards, prowl the reservation late at night, once the gates are closed to the public. Our trip is to see some of the reserves less ferocious creatures, the Hyraxes and Nubian Ibexes for which the centre is best known.
Biologically speaking, hyraxes are intriguing animals. Although they resemble large cavies or, perhaps, morbidly obese guinea pigs, their closest relatives are, in fact, the elephant and “sirienia”, such as the dugong and manatees. In keeping with their curious ancestry, they have a number of strange physiological features. For a start, hyraxes do not have a (virtually) constant body temperature, throughout the day, like other mammals do. Instead, their temperature fluctuates each day and they bask on rocky outcrops in the morning sunshine to warm themselves up, much as lizards do (see ref. 1, below). Other quirks of hyraxes include the fact that the males lack a scrotum, with their testes being located inside their bodies, near their kidneys (an anomaly they share with elephants and dugongs). As social creatures, hyraxes also have a complex communication system, using a mixture of whistles, snorts and chattering noises to “talk”, in a sort of rudimentary “language”, which even has regional dialects (see ref. 2.).
Although there are four hyrax species in the world (see ref. 3), the Cape Hyrax, Procavia capensis, is the only species to occur in Ein Gedi or, in fact, anywhere in Asia. The other species (the yellow-spotted hyrax, Heterohyrax brucei, the Western Tree hyrax, Dendrohyrax dorsalis and the Eastern- or Southern- Tree Hyrax, Dendrohyrax arboreus) are found only in Africa.
I am very keen to see the reserve’s hyraxes in-the-flesh, but am hopeful, rather than optimistic. My guide book talks of “dozens of hyraxes ...appear[ing] to stand to attention at the mouth of the wadi”, but I have heard much the same about other nature reserves in the past and been unable to see anything. With wildlife spotting, there is always an element of luck. Ein Gedi’s other famous inhabitants, Nubian Ibexes, though, make an appearance before we have even reached the reservation. Pulling sharply to the side of the road, my companion points out two that are just feet away from us, fleeing rapidly and almost vertically up the embankment to our right and away from the noise of our car. Despite the sheer terrain, the animals have almost made their get-away before I can even remove my camera from its case on my knees; it is a graphic demonstration of their agility.
The Nubian Ibex, Capra nubiana, for all its impressive horns and romantic name, is really “just” a wild relative of the goat; it is one of nine species in the genus Capra, of which six are currently threatened in the wild. None the less, it is an iconic species and popular among certain exotic goat breeders for its comparative hardiness (relative to other Ibexes). The males, famously, sport large, thick, curved horns on their heads, prominent “goatee- beards” and have a brown stripe along their backs, whilst the females have smaller, lighter horns, and lack the stripes and beards. Outside of the October mating season, males and females tend to live fairly separate lives in small herds or groups of related individuals. At this time of year (mid May), we hope to catch sight of some of this years’ young, since kidding usually occurs around March and the young take around 3 years to reach adulthood (see ref. 5). According to the IUCN’s Red List of Threatened species, one of the biggest restrictions on the distribution of Nubian Ibexes, across their range is the availability of water, or, more precisely, the lack of it. Looking at the surrounding desert scenery, here, it is hard to imagine that the adults or their kids find much water or food, since the landscape is more like Mars than the Middle East. Indeed, outside of the reserve, the only visible vegetation consists of very occasional clumps of small plants near the road and in the cracks in the rocks and the only water is the undrinkable saline expanse of the Dead Sea to our left.
The entrance to the Ein Gedi reservation is marked by a thatched hut and a scattering of umbrella-thorn acacias (Acacia tortilis) that grow in the more northerly of the reserve’s two wadis, “Nahal David”. We turn sharp right, park and enter the reservation on foot. The air is hot and dry and the sun is dazzlingly bright. Behind us is The Dead Sea and, in front, towering over the reservation, is the peak of Mount Yishay, marking the edge of the Judean plateau, some 200 metres above sea level and 624metres above us.
Inside the main gates, the vegetation here is scrubby, but none-the-less, vastly more abundant than in the surroundings. Almost immediately, we come across a mixed grove of Twisted acacias (Acacia raddiana). They and the other trees beside them are much taller than the umbrella-thorn acacias trees we passed earlier and have a different canopy shape; however, that is of little concern because there, on the ground in front of virtually the first tree, is a hyrax, “happily” sunning himself in the late afternoon sunshine. Above and slightly behind him are two more hyraxes, eating clumps of leaves and periodically chattering to one another. They are remarkably unperturbed by our presence and it is easy to watch and photograph them at close range. Periodically, they move from one cluster of leaves or one branch to another, with a slow, graceful gait, much like that of a koala. On the ground, they use their legs independently, rather than hopping like a rabbit usually does, which makes perfect sense and yet is surprising to watch at the same time. Their most striking feature, though, is their feet, since they have five toes on their front legs and only 3 on their rear ones, with curious, hoof-like nails on two of the toes. The soles of hyrax feet are optimized for climbing, by having exceptionally soft and elastic skin to increase friction with tree branches and specialized muscles that help the feet work “almost like a suction cup” (see ref. 5). For obvious reasons, we cannot take a close look at the soles of the hyrax’s feet, but we can see the animals move with poise from branch to this twig to branch again, eating all the while.
Having spent some time observing Ein Gedi’s resident hyraxes, we start the slow climb up the banks of the wadi, to David’s fall at its apex. In places, there are railings or steps cut in the rock, elsewhere, the route is just a path between the boulders that is punctuated by glimpses of the stream to our left and its periodic waterfalls and pools. As we climb the ravine, we catch sight of distant ibexes, on the flanks of the mountains ahead. They are so well concealed that sometimes their presence is only revealed when they disturb the dirt on the ground and are betrayed by the resulting dust cloud. So often in nature, an animal that looks very bright and unmissable in a laboratory or zoo completely disappears in its natural landscape. I have seen it elsewhere, with bright blue and green butterflies vanishing amongst lush rainforest foliage and with deep red jellyfish becoming imperceptible in the dim light of the ocean. Here I am observing it again for, even fairly close-up, the ibexes are brilliantly camouflaged and their movement is virtually silent.
The summit of our Ein Gedi tour is David’s Fall, which is a pretty and peaceful waterfall, rather than a spectacular one. Its walls are carpeted green with maidenhair ferns and moss and shrubs and Sodom apple plants (Calotropis procera) have taken-root in crevices higher in the rock face. It is said that Melanopsis species river snails and river crabs (Potamon potamois) live in the freshwater pools here (see ref. 6), but there is no sign of them, nor of any larger fauna, now. Instead, there is just the sound of the water falling into the pool and running off into the distance behind us.
We begin our return journey as the reserve closes for the evening: the path has become noticeably quieter now that the tourists have started to leave. Clearly this is attractive to the ibexes, since we have only gone a few paces before a family group of four females plus a kid appears out of nowhere in front of us, fords the wadi at leisure and climbs the far bank, browsing edible leaves as they pass. The reserve is open only for fairly short hours each day precisely for this reason- to allow its animals peaceful access to the water and plants here, without disturbance from humans. Although Ein Gedi’s hyraxes seem completely unphased by mankind, its ibexes are more timid, so our timing in leaving - or theirs in arriving- is impeccable. Either way, it is an unexpected bonus and a very welcome reward at the end of a long hot day.
Hyraxes and Ibexes are among the animals that can be seen in Ein Gedi (also called “En Gedi”) nature reserve, in Israel, as well as in Jordan’s Mujib Nature Reserve (also known as “Arnon” or the “Wadi Mujib”), on the opposite, Eastern, bank of The Dead Sea.
Victoria Neblik is a Research Biologist, Magazine contributor and former University Lecturer in Science Communication. Dr Neblik’s public talks include “Birds, Butterflies and Men of War”; contact details are on TheGreatestMinds.Org
Bibliography and More information:
1. More information on hyrax temperature regulation can be found in
“Procavia capensis, Rock Hyrax”, by Erin Linderman http://animaldiversity.ummz.umich.edu/accounts/Procavia_capensis/ and
“Procavia capensis” by Nancy Olds and Jeheshkel Shoshani, (1982) http://tinyurl.com/kmtj3dm
2. “Syntactic structure and geographical dialects in the songs of male rock hyraxes” by Arik Kershenbaum, Amiyaal Ilany,Leon Blaustein and Eli Geffen
http://rspb.royalsocietypublishing.org/content/early/2012/04/15/rspb.2012.0322.full - aff-2 was published in Proceedings of the Royal Society, B (biological Sciences), in April 2012, article reference- doi: 10.1098/rspb.2012.0322.
It is available online at http://tinyurl.com/m8ngx7k
3. More information on hyrax species can be found on the Tree of Life web project, http://tolweb.org/Eutheria/15997 , http://tolweb.org/Hyracoidea/15982 and http://tolweb.org/Dendrohyrax/16174.
4. Information on the Nubian Ibex can be found at http://tinyurl.com/lnot9ca as well as on http://tinyurl.com/lhtdo8g.
The IUCN’s Red List entry for the Nubian Ibex is online at- http://www.iucnredlist.org/details/3796/0
5. “Hydracoidea, Hyraxes”, Phil Myers, University of Michigan Museum of Zoology, http://animaldiversity.ummz.umich.edu/site/accounts/information/Hyracoidea.html
6. “En Gedi Nature Reserve”- Guide and Map, English version –pub: Israel Nature and Parks Authority, www.parks.org.il
7. “Israel and the Palestinian Territories, The Rough Guide”, 2nd Edition, by Daniel Jacobs (with Shirley Eber and Francesca Silvani), Pub: Rough Guides Ltd, 1998.
8. More information on various Ibex species can be found on the Tree of Life web-project (http://tolweb.org/Capra/51066) and in their individual wikipedia entries,
9. Tristram’s Grackle is described in “The Birds of the Western Palearctic Concise Edition.”, by D. W. Snow, & C. M. Perrins, Pub: OUP, 1998 ISBN 0-19-854099-X.),
Nubian Ibex beside the Dead Sea road.The Nubian Ibex is one of nine species in the goat family (genus Capra), the others being the Alpine-, Abyssinian-, Spanish- and Siberian Ibexes, the East- and the West-Caucasian Turs, the Markhor and the Wild Goat. (The domestic goat and the wild goat are considered to be the same species).
Tristram’s Grackle, Onychognathus tristramii, is a common bird in Ein Gedi. It is known to eat parasites that it grooms off Nubian Ibexes and domestic cattle, although it also favours berries of the grey-leaved cordial (Cordia sinensis) and various other foods.
(c) Victoria Neblik at The GreatestMinds.Org, 2017 | All Rights Reserved
The Barren landscape of the Judean desert
bordering the Ein Gedi reserve.
Rock hyrax poised for feeding in the reservation’s trees. The Cape Hyrax is found in Southern Africa, Saharan and Sub Saharan Africa, Egypt, Israel, The Lebanon and the Arabian Peninsula.
A lush oasis: a waterfall in the Ein Gedi reserve.
Entrance to Ein Gedi; Mounts Yishay (pictured) and Zeruya overlook the Ein Gedi reserve and mark the edge of the Judean Desert Plateau, some 200metres above sea level.
Rock hyrax resting on the pipe’s of the reservation’s drip-irrigation system. Rock hyraxes spend a lot of their time resting, however one recent study indicates that their sleep is complex and involves unusual patterns of brain activity compared with other animals.
Up above: rock hyrax feeding in the reservation’s trees.
Rock hyrax poised for feeding in the Ein Gedi wildlife reservation.
Just Browsing: three female Ibexes and a kid climbing David’s ravine as the last tourists leave for the day.
David’s Fall at the peak of Nahal David is home to various water-loving plants, including maidenhair ferns, Adiantum capillus.
The Entrance to Ein Gedi Reserve and Mount Yishay.