Vol. 9, pp. 30-33

Asiatic Herpetological Research

2001

Notes on the Diet, Survival Rate, and Burrow Specifics of Uromastyx aegyptius
microlepis from the United Arab Emirates
Peter L. Cunningham
P.O. Box 17258, AlAin. United Arab Emirates, email: plc@ emirates. net.aeofplant
Uromastyx aegyptius microlepis are almost exclusively herbivorous and feed on a variety
with Pennisetum divisum being extensively utilized in the United Arab Emirates. The survival rate, asAbstract.-species

determined over a one year period without any rainfall is <50%. Burrow openings are mainly aligned in aburrow entrance size being 60x155 cm. Temperatures measured
southerly and easterly direction with the average
at 30cm down the burrow entrance are on average 6°C lower than the ambient temperature.

Key words.- Reptilia. Squamata. Agamidae, Uromastyx aegyptius microlepis. United Arab Emirates, ecology

Figure 2. The study site and habitat of U. a. microlepis
in Abu Dhabi.

982, Highveld and Slimani 1998, Jongbloed 1997,
Manthey and Shuster 1996).

Material and Methods
Figure I.The Spiny-tailed lizard, Uromastyx aegyptius
microlepis.

Twenty mature Uromastyx aegyptius microlepis individuals in a scattered population, ±35 km northwest ofIntroduction

Al Ain (24°25'07"N and 55°35'01"E; Fig. 2) in theAbu Dhabi Emirate of the United Arab Emirates

Uromastyx aegyptius microlepis (Spiny-tail Lizards;
and occurFig. 1) belong to the Family Agamidae
ArabianPeninsula,
Iran,
theIraq and Jorthroughout(UAE), were observed for one full day each (sunriseto sunset). These observations took place during sum-dan (Arnold 1986. Leviton et al. 1992).

Theyarediurnal ground dwelling lizards that may reach sizesof up to 60 cm and are generally yellowish-grey inmer (May and June 1999) and winter (December 1999
and January 2000), respectively. I spent 480 observation hours studying these lizards.

Direct observations

colour with an impressive spiny club-like tail. Adultof plant species utilized during their feeding bouts
was conducted using an 8x40 binocular over a dis-U. a. microlepis are documented as being mainly her-tance of

100m

behavior.

Tracks were also followed once the lizardsbivorous, although insects form part of their diet,while juvenile lizards are thought to be mainly insectivorous (Arnold1984,

so as not to influence the feeding

had retreated underground to confirm sightings. Fecal

Baha El Din 1996, Brown
pellets

were collected forlater

analysis.

Burrow

Asiatic Herpetological Research

2001

Amaranthaceae (Cockscomb family): Aerva jav-information (orientation, burrow entrance height andwidth, temperature above ground and 30 cm downburrow) was collected from 25 active burrows once
the lizards had retreated.

Vol. 9, p. 31

anicaAsclepiadaceae (Milkweed family):Leptadenia

pyrotechnica

Survival rate was determined for the 20 study individuals by investigating their burrows for any signs ofactivity in June 2000, one year after the first observations were made.

Boraginaceae (Borage family): Moltkiopsis

cili-ata, Heliotropium kotschyi

Chenopodiaceae (Goosefoot family): Haloxylon
salicomicum
Cucurbitaceae (Gourd family): Citrullus colocyn-Results
thisDiet. Uwmastyx aegyptius microlepis utilized the fol-Leguminosae (Pea family): Tavemiera cuneifolia

lowing 10 plant species:

Polygalaceae

Class Monocotyledonae

Polygala

eri-individuals

first(Milkwort family):opteraGramineae (Grass family): Pennisetum divisum,
Stipagrostis plumosa

Survival Rate. Ofobserved

Class Dicotyledonae

inthe20study

May 1999, only 9 were still present inJune 2000.

Table 1 Vegetation selected by Uromastyx aegyptius microlepis as documented by different authors from the*Arabian Peninsula. Pulicaria glutinosa observed being utilized in other areas although not in the present study.

area.

This Study

UAE- Abu Dhabi

Jongbloed(1997)
UAE - Sharjah

Mandevile(1965)
Saudi Arabia

Aerva javanica
Aristida plumosa

Astragalus gyzensis
Citrullus colocxnthis

Citrullus colocynthis

Fagonia sp.
Haloxylon salicomicum
Heliotropium kotschyi

Horwoodia dicks on eae
Launaea capitata
Leptadenia pyrotechnica
Moltkiopsis ciliata

Moltkiopsis ciliata

Neurada procumbens
Pennisetum divisum capitata

Pennisetum divisum

Plantago boissieri
Polygala erioptera*Pulicaria glutinosaStipagrostis plumosa

Tavemiera cuneifolia

Zygophyllum sp.

Asiatic Herpetological ResearchVol. 9, p. 32

2001

Burrow specifics (n=25). Burrow openings were ori-would show a preference for insects during autumn

entated as follows:

and spring although

North 2, West 3, South 12 (S/West: 4, South: 5, S/

itexpected that the lack ofis

insects in the diet could be contributed to the fact thatmost insects, Tenebrionidae at least, are crepuscular

East: 3) and East 8.

Mean average burrow opening height and width
was 61 cm and 155 cm (n=25), respectively.

Mean average temperature at a depth of 30 cm
down the burrow was 38°C (n=25). The ambient temperature measured at 1.5

m above ground at 13h00

was 44°C.

or nocturnal (Tiger 1996).

Other items consumed by Uromastyx as observed
during the fecal analysis of the pellets include: sheepdroppings (17 pellets), date kernels (4 pellets) andfeathers (3 pellets).

Itisexpected that above men-tioned items are consumed erroneously by the lizards

Brown (1982) suggests
sheep droppings be consumed to extract undi-

as insect material although
thatDiscussion
Diet.

Ten perennial plant species are selected by Uro-gested plant material. If the sheep droppings, datekernels and feathers were consumed as insect mate-would suggest that the lizards would prey on

mastyx aegyptius microlepis as observed during therial,

study period, with the coarse desert grasses Pennise-insects more often if they were more readily available.

ittum division and Stipagrostis plumosa being favored.

Survival rate. Nine (45%) of the 20 study individuals

Jongbloed (1997) identified 3 plant species selectedby the lizards from the Sharjah area in the UAE whilesurvived a period of one year from May 1999 to June

Mandaville (1965) identified 8 plant species from thestomach contents of six Uromastyx aegyptius specimens from Saudi Arabia (See Table 1). Foley et al.
(1992) identified 23 plant species, mainly annuals,
selected by the same species in Israel.

As no rain had fallen during the study period noannuals were observed and therefor the exclusionfrom the diet.

Itwould therefor be expected that more

plant species, especially flowering annuals, would beutilized after rains.
Rainfall is highly variable(± 100mmp. a.)and unpredictable in the UAE (Bot-tomley 1996) forcing the lizards to rely on the available perennials. According to Zari (1996 and 1998)
Uromastyx philbyi feed on a variety of annual grasses

and perennial shrubs in western Saudi Arabia. Highand Slimani (1998) indicate Uromastyx acan-field

thinurus's preference for the family Chenopodia (fathen/spinach) as well as the salt tolerant Artiplex genus
and a wide variety of ephemeral plants after rains inMorocco.

An analysis of 170 fresh adult fecal pellets (852000. Three of the 1 1 missing individuals were foundas severely malnourished carcasses.

The other 8 indi-viduals not accounted for are presumed to have suc-

cumbed below ground

in

their

which were covered by sand.

burrows, some of

No signs of emigration

were determined. No rainfall occurred during thisperiod in the study area. The area is also frequented
by large numbers of domestic camels and sheep,

which compete directly with the lizards for the availIt is suggested that the lack of rainfall andable food.

lack of annual plants as a result of this, together withthe extra pressure of domesticated stock, resulted in
the high mortality observed.

Burrow specfics. Burrowopenings

weremainlyaligned to the south and east with 80% of the burrow

entranced facing this way. During summer, temperatures consistently reach between 40°C and 47°C

between lOhOO and 16h00.

North and west facing

burrow entrances would be hotter than burrows facing
in other directions, especially during midday. During
winter the lizards would also benefit from the south-erly

orientation

warming

the burrows quickerandsummer and winter, respectively) confirmed the her-more effectively.

bivorous nature of U. a.microlepis as only one pellet

predominantly from the northwest and can cause
severe sandstorms locally known as "shamal" (El-(<1%) contained insect remains, that of a Tennebrionid beetle.
(1998)

adultAccordingfecal

topellets

Highfield and Slimaniof U. acanthinurus in

Morocco contained 6% insect matter. Brown (1982)
also mentions U. a.microlepis feeding on locusts fromthe UAE.

It still

has to be investigated if the lizards

Ghonemy 1985).

Wind direction during summer isThis causes lizard whose burrows

face that direction to spend more time on den clearing,a time consuming an energetically costly affair espe-

Asiatic Herpetological Research

2001

cially during summer when plant availability and palatability are low.

Burrow size is often related to the size of the resiThe mean average size of 61 x 155 cm

Vol. 9, p. 33

Brown, J. N. B. 1982. Spiny-tailed Agamid - Uromastyx microlepis (Arabic "Dhub"). Emirates NaturalHistory Group Bulletin Nol6:20.

Uromastyx colony.

Cunningham. P. L. 2000. The use of burrows by Hoopoe Lark (Alaemon alaudipes). Tribulus 10. :2

Bigger burrow openings have higher temperatures at adepth of 30 cm, especially when facing to the north orEl-Ghonemy, A. A. 1985. Ecology and flora of Al Ain
Region. University of the United Arab Emirates, Alwest.

Ain.

dent lizard.

(n=25)

isindicative of an adult

The mean average temperature of 38°C, during theheat of the day, at a depth of 30 cm down the burrowis on average 6°C lower than the ambient temperature.

This gradient is imperative to the survival of the lizards.

During the fieldwork it was often found that thelizards were resting in the burrows at a depth of justover 30 cm, scurrying deeper once the thermometer11.

Foley. W. J., A. Bouskila, A. Schkolnik and I. Choshniak. 1992. Microbial digestion in the herbivorous liz-Uromastyx aegyptius (Agamidae). Journal of
Zoology, London. 226:387-398.
ard

Highveld, A. C. and T. Slimani. 1998. The SpinyTailed Lizard at home: Uromastyx acanthinurus inSouthern Morocco. Reptiles - Guide to keeping rep-was inserted down the burrow. According to Brown(1982), the burrows can be more than 6 feet long andtiles and amphibians, July3 to 4 feet deep in the form of a spiral.

Jongbloed, M. 1997. Observations in a Dhub colony.
Tribulus 7.2:23-24.

Jongbloed(1997) confirms this depth even indicating reports ofup to 12 feet deep burrows. The same author mentions that an excavated burrow of 5 feet in depth was 2
feet acrossand1foot high andstill

not atitsend.

Burrows do not only serve as thermoregulatory
havens for Uromastyx aegyptius microlepis, but also

1998: 76-87.

Leviton, A. E., S. C. Anderson, K. Adler and S.A.

Minton. 1992. Handbook to Middle East Amphibians
and Reptiles. Scociety for the Study of Amphibians

and Reptiles, Oxford, Ohio. 252 pp.

for the Desert Monitor (Varanus griseus) (Pers.obs.)

Lovegrove, B. G. and A. Knight-Eloff. 1988. Soil andburrow temperatures, and the resource characteristics

and certain Larks (Cunningham 2000, Williams et al.

of the social mole-rat Cryptomys damarensis (Bathy-Williams et al. (1999), states that Uromastyxergidae) in the Kalahari Desert. Journal of Zoology,1999).

burrows can potentially reduce Hoopoe Lark (Alae-mon alaudipes) water loss by as much as 81% during
the hottest periods during summer. Temperatures at a

depth of 30 cm are relatively stable therefor being
exploited by many desert dwelling animals (Love-grove and Knight-Eloff 1988). Burrows are thus aneffective way of escaping predators, the harsh desert

environment as well as controlling water loss.

London 216:403-413.
Mandeville,eastern United

Arab Emirates. Journal of Zoology,

London 204:329-354.
Arnold, E. N. 1986. A key and annotated checklist toand amphisbaenians of Arabia. Fauna ofSaudi Arabia 8:385-435.

PlantseatenbyUromastyx

Manthey, U. and N. Schuster. 1996. Agamid Lizards.
T.F.H. Publications Inc., USA.
J.

arthropods

Arnold, E. N. 1984. Ecology of lowland lizards in the1965.

Society 62(1): 161 -163.

Tiger, B.

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