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T
he Whorl-tailed Iguanas (Cyclura Harl.
[translator’s note: “Harl.” Refers to
Richard Harlan, an American paleontolo-
gist and comparative anatomist who

described many American and “exotic” species of
amphibians and reptiles]) are distinguished from
Common Iguanas [= Iguana spp.] by their denti-
tion, the smaller dewlap, and the more weakly
developed gular fold. Pattern and scalation is sim-
ilar to that of other iguanas, except that the dorsal
surface of the tail is distinguished by a ring of
enlarged scales following three or four rows of typ-
ical scales. Although these enlarged scales are not
particularly long, their collective tips form a whorl-
like band of erect spikes around the tail. The dor-
sal crest may be interrupted in the shoulder and
hip regions. The teeth, which appear to increase in
number with age, are not serrated, but are three-
sided, as in Common Iguanas, and those on the

pterygoid and sphenoid are small but numerous.
Femoral pores are distinct and form a long row on
each leg. All species are terrestrial and are found
primarily in sandy areas where they live in burrows
which they excavate for themselves.

The best-known species is Cyclura lophoma
Gosse [this “species” is now known to consist of
several distinct taxa, including C. collei, C. nubila,
and C. cychlura; Philip Gosse was the author of the
delightful A Naturalist’s Sojourn in Jamaica, pub-
lished in 1851] of Cuba, Jamaica, and the
Bahamas. This form may reach a total length of

H I S T O R I C A L  P E R S P E C T I V E
89IGUANASeptember 2003

Whorl-tailed Iguanas*

Franz Werner

* excerpted and translated from Franz Werner (1913. 
Die Lurche und Kriechtiere von Alfred Brehm. Zweiter
Band: Kriechtiere (Schuppenkriechtiere). In O. z. Strassen
(ed.), Brehms Tierleben. Allgemeine Kunde des Tierreichs.
4th ed. Bibliographisches Institut, Leipzig and Wien.
Translated by R. Powell.

Adult male Jamaican Iguana (Cyclura collei); at the time Werner wrote this article, the Jamaican species plus populations in
Cuba (C. nubila ) and the Bahamas (C. cychlura) were all known as C. lophoma.  Photograph by Jeff Lemm.



1.2–1.3 m, of which the tail comprises about 70
cm, and is distinctive because of its relatively low
dorsal crest, which is composed of linked, some-
what sickle-shaped spines, and which may be con-
tinuous at the nape and base of the tail or distinctly
separated at one or both places. The snout is cov-
ered by three pairs of large, multi-sided, tubercu-
late plates that are separated from one another by
small scales. Plates of variable size, those that are
medially located the most prominent, characterize
the forehead, and on each side of the lower jaw is
a row of large, quadrangular, heavily keeled scales.
Overall color of the body and limbs ranges from
slate gray to brownish
green. A few diagonal
lines passing over the
shoulder and several
broad crossbands that
extend from the dorsal
crest to the belly are
dark olive-brown. The
tail is circled by regu-
larly spaced light and
dark olive-green bands.

According to
Gosse, Whorl-tailed
Iguanas live in only a
few places on Jamaica.
They were relatively
common on the lime-
stone hills that extend
from Kingston harbor
to the so-called Goat Island and are well known
for the large numbers of feral goats, pigs, and
chickens that live there. Otherwise, one may find
these iguanas with some regularity in the flats that
separate the coastal hills from higher mountains of
the interior, but only in areas that feature large
numbers of old, hollow tree trunks. These lizards
appear to have no particular fondness for water,
although, like their relatives, they know how to
swim rather well. A fortunate circumstance made
it possible to learn more about the Whorl-tail than
many of its relatives. Two individuals lived in an
old Acacia on the estate of a Mr. Minot for 16
months, providing him with the opportunity to
observe them for an extended period of time. A
friend of the owner had fortuitously discovered the
two animals, but a blow with a riding crop fright-
ened them so much that for weeks thereafter they

emerged from their lair in only the most surrepti-
tious fashion and immediately sought refuge in the
hollow tree when any human approached too
closely. Subsequently, Minot forbade any further
disturbance of the animals and, over time, they for-
got their fright and eventually became so tame that
they consented to regular and proximate visits by
their landlord. As the day warmed, one of the ani-
mals would emerge from its tree hollow and hang
from the bark or crawl out on a thin, dry branch
to bask in the sun. It would often spend the entire
day doing little else, with nary a care for the rest of
its environment. Minot never saw it hunting

insects and only once
did he surprise a lizard
while it was eating.
This occurred when
the sun broke through
the dark clouds after a
heavy rain and the veg-
etation had largely
dried. One of the
Whorl-tails left the
tree, covered about 10
m of ground with slow
steps, moving only one
leg at a time, until it
approached a stand of
so-called Guinea-grass.
Tearing off mouthfuls
at a time, it swallowed
large masses without

any trouble. Startled by the observer whom it sud-
denly noticed, it rushed back to the tree, not so
much running or walking as moving with a rapid
series of frog-like hops. Once there, it ducked into
its hole and quickly disappeared from sight.

Minot made particular note of the fact that the
fleeing Whorl-tail showed no inclination to seek out
water, as other iguanas are wont to do under simi-
lar circumstances. As a matter of fact, these Jamaican
animals showed little interest in water of any kind
and seemed to tolerate even the driest conditions
without drinking. The two inhabitants of the tree
were obviously a pair, since they differed from one
another in size and coloration. They also lived har-
moniously together, but they were never seen out
of the burrow at the same time. Eventually, a good-
for-nothing youngster ended the observations, lay-
ing near the tree and heartlessly shooting the two

90 IGUANA Volume 10, Number 3

Head of a Rhinoceros Iguana, Metopocerus cornutus Daud.
Photograph by L. Medland, F.Z.S. – Finchley, N.



harmless creatures one after the other. Minot
opened the carcasses of the shamefully murdered
animals and found both stomachs filled with the
previously mentioned grass.

Barbour [Thomas Barbour, an American her-
petologist who traveled widely throughout the
West Indies during the first half of the 20th cen-
tury] recently noted that the Whorl-tail has been
brought to the verge of extinction by the presence
of the introduced Mongoose (Herpestes griseus
[= Herpestes javanicus]) and is now found only on
Goat Island, which the interloper has yet to reach.

Although generally retiring, preferring to
retreat in the face of humans whenever possible,
the Whorl-tail is quite
brave and quite capable
of defending itself in an
emergency. The tail is a
weapon that should
not be underestimated
and which can be used
with great effect. Easily
aroused like all iguanas,
the Whorl-tail will
respond with consider-
able wrath when cor-
nered, inflating itself,
erecting the dorsal
crest, gaping to show
its sharp teeth, staring
darkly at its antagonist,
and readying itself for
an attack. If one con-
tinues to threaten the
beast, it will turn around quickly and deliver a
hefty blow with its tail, and then immediately turn
the other way in anticipation of delivering another
strike from the other side. Hill [an unknown per-
son] had been alerted by natives to the danger
posed by this animal and had been clearly warned
against a careless approach. The spikes on the
powerful tail are sufficiently sharp that the animal
can readily inflict a most painful wound. Dogs that
approach one carelessly often are severely injured.

Whorl-tails, possibly as a consequence of their
diet, have such an unpleasant odor that even ants
refuse to touch them — or at least to strip the flesh
from a carcass thrown on their colony. These ani-
mals appear not to be hunted as eagerly as their
relatives in Mexico.

The Rhinoceros Iguana, Metopocerus cornutus
Daud. [Metopocerus is now considered synony-
mous with Cyclura; “Daud.” refers to François-
Marie Daudin, a French naturalist who wrote
Histoire Naturelle des Quadrupèdes Ovipares in
1800, in which he formally described the
Rhinoceros Iguana], is a mighty beast found in
San Domingo [a reference to Hispaniola and,
more precisely, to the Dominican Republic]. It
resembles the Green Iguana (Iguana tuberculata
[= Iguana iguana]) in having teeth with serrated
crowns and the Spiny-tailed Iguanas [= Cteno-
saura spp.] of Middle America in color, size, build,
and lifestyle — but is readily distinguished by the

three large, cone-shaped, horn-like scales on the
top of the snout of adult males. Old males also are
characterized by their bulging jowls and exceed-
ingly large heads and make a considerable impres-
sion that is enhanced further by their proud pos-
ture and lively eyes. The powerful bite and the
strong, spiky tail make the Rhinoceros Iguana a
worthy opponent.

Rhinoceros Iguanas are overwhelmingly terres-
trial, consume both vegetable and animal matter,
and in captivity can be readily maintained on a diet
of fruit, juicy leaves, and strips of raw meat.
Ditmars [see the appended biographical sketch]
indicated that they even overpower rats and young
chickens, shaking larger prey until it is torn into
pieces. Given enough space and heat, these lizards

91IGUANASeptember 2003

Rhinoceros Iguana.



92 IGUANA Volume 10, Number 3

B I O G R A P H I C A L  S K E T C H :  
Raymond L. Ditmars 

(1876–1942)
Raymond Ditmars was America’s first great popularizer of reptiles. He was born in Newark, New Jersey

and caught his first snakes at age 12 at Gravesend Bay near Brooklyn, New York. In 1893, Ditmars was hired
by the entomology department at the American Museum of Natural History, but resigned in 1897 to take
higher paying positions unrelated to his interest in animals. In 1898, as a reporter for The New York Times,
one of his beats was the newly-formed New York Zoological Society. Shortly after the zoo opened, Ditmars,
barely 23 years old, was hired as Assistant Curator of Reptiles and his private collection become the nucleus
of the zoo’s reptile displays.

Ditmars published eight herpetological books, plus a dozen more about other animals or tales of 
his work or travels. The Reptile Book, published in 1907 (an expanded edition was published in 1930) 
established his reputation. This volume and several others (Reptiles of the World, 1910, revised 1933; Snakes
of the World, 1931; Reptiles of North America, 1936; and Field Book of American Snakes, 1939) had an
enormous public influence, kindling a widespread interest in reptiles
and resulting in several generations of professional herpetologists,
including many still active today, who can trace their interest to one
or more of Ditmars’ books.

Ditmars was often dismissed as a mere showman, mainly
because he wrote highly popular books for the general public, 
but he also made substantive scientific and public contributions.
He pioneered techniques for treating diseases of reptiles, 
he was a major organizer of the first effort to establish
an antivenin institute in America, he produced influ-
ential nature films, and he led the development of the
Bronx Zoo into the first rank of the world’s zoos.

Source: Adler, K. 1989. Herpetologists of the past, pp. 5–141. 
In K. Adler (ed.), Contributions to the History of Herpetology.
Society for the Study of Amphibians and Reptiles, Contributions 
to Herpetology, Number 5. Ithaca, New York.

Raymond L. Ditmars (photograph
courtesty of Kraig Adler).

do well in captivity and have become staples in
zoos that maintain collections of reptiles.
Rhinoceros Iguanas are lively, shy, and careful, and
do not become tame in captivity for some time. A
male, kept by Werner [the author] in a cage for
several years, gaped when approached, exposing its
dark purple throat, but did not bite, instead

retreated farther into the cage and, only when
approached even more closely, did it turn and
strike with its tail. When removed from its cage, it
exhibited an extraordinary strength, resisted des-
perately, and flailed its tail violently. 


