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vegetation. Together with previous work
on acoustic communication, these data
show that animals with very different
sensory ecologies can face similar envi-
ronmental constraints and adopt remark-
ably similar strategies to overcome those
constraints.

Natural History of 
St. Vincent Dwarf Geckos

STEINBERG ET AL. (2007. Journal of
Herpetology 41:326–332) documented
population densities, microhabitat prefer-
ences, desiccation rates, and diets of
Sphaerodactylus vincenti on St. Vincent,
West Indies. The authors predicted and
observed high densities (to 5,625/ha) in
moist, shaded leaf-litter. Such microhabi-
tats provide refuges, access to prey, and

protection against water loss, as S. vincenti
is vulnerable to high desiccation rates.
They found significant differences in mass-
specific water-loss rates and body mass
between conspecific populations at differ-
ing elevations, with larger geckos less resist-
ant to water loss living in more mesic envi-
ronments at higher elevations. Stomach
content analysis suggests that S. vincenti is
a dietary generalist that feeds on a variety
of small arthropods primarily by day.

132 IGUANA  •  VOLUME 14, NUMBER 2  •  JUNE 2007 NATURAL HISTORY RESEARCH REPORTS

Virgin births 
at the London Zoo

Four Komodo Dragons (Varanus komod-
oensis) hatched at the London Zoo were
the result of parthenogenesis, the devel-
opment of an egg without fertilization by
a sperm. A clutch of dragon eggs laid in
August 2005 fascinated reptile keepers.
The female had arrived in London on
loan from Thoiry Zoo in France in early
2005, and the clutch of eggs was laid
more than two years after she had last
lived with Thoiry’s male. Initially, keep-
ers suspected sperm storage, but Curator
of Herpetology, Richard Gibson, wasn’t
entirely convinced and resolved to inves-
tigate further.

Genetic fingerprinting techniques at
Liverpool University confirmed that the
four dragons were actually the result of
parthenogenesis. The female later mated
with the London Zoo’s male and subse-
quently laid a second clutch of eggs from
which a single, “normal” dragon hatched,
demonstrating that Komodo Dragons

can switch reproductive strategies
depending on the availability of a mate.

Richard Gibson said: “I am delighted
that the mysterious parentage of our
Komodo Dragon babies has been solved,
and that we have discovered something
new to science at the same time. Knowing
that the world’s largest lizard can repro-
duce like this suggests that many other
reptiles may also do this more often than
we thought, and may lead to changes in
the way we manage this and other species
in breeding programs. This discovery also
raises important questions about the nat-
ural history of dragons in the wild, and

will therefore help to safeguard the future
of the species.”

Zoological Society of London
21 December 2006

Homing Behavior in Baby Snakes
We all know that children behave like
their parents in many ways, especially as
they grow older (even though many chil-
dren deny it!) — and most of us suspect
that the similarity is partly due to learn-
ing, and not just genetics.

Researchers from the University of
Sydney have discovered that baby snakes
also behave like their parents, and prob-
ably for similar reasons as in humans. For
more than a decade, Drs. Greg Brown
and Rick Shine have been studying the
ecology of small non-venomous
Keelback Snakes (Tropidonophis mairii)
on the floodplain of the Adelaide River,
on the outskirts of Kakadu National Park
in the Northern Territory.

N E W S B R I E F S

Puerto Rican Crested Anoles (Anolis cristatel-
lus) increase the speed of body movements
used in territorial signaling to improve com-
munication in visually “noisy” environments.

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Four Komodo Dragons (Varanus komodoen-
sis) hatched at the London Zoo were the
result of parthenogenesis, the development of
an egg without fertilization by a sperm.

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Populations of larger St. Vincent Dwarf Geckos (Sphaerodactylus vincenti) living in more mesic
environments at higher elevations are less resistant to water loss.

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One of their latest findings (just
published in the journal Biology Letters)
is that once they grow to adulthood and
are ready to reproduce, female snakes
return to the same area where they were
hatched. So, many snakes probably lay
their own eggs in the same nest as that
from which they hatched, at least one
year previously.

Professor Shine said: “One of the
reasons that we behave like our parents is
that our behavior is strongly molded by
our early experiences — and we have
found that the same thing happens in
snakes as well. We have known for many
years that baby salmon somehow recog-
nize the characteristics of water from the
streams where they hatch, and return to
the same stream many years later to
breed. We’ve found exactly the same
thing in snakes. Even though a Keelback
Snake wanders widely during the first
year or two of her life, she returns to her
original birthplace when it’s time to lay
her own eggs.”

Why do snakes return to lay their
eggs at the same place that their mothers
did, years before? The answer is probably
that the nest was a good one — other-
wise no babies would survive to return.
So, evolution has favored snakes that are
able to remember where they hatched,
and return there when the time comes to
produce their own offspring.

These results have strong implica-
tions for conservation, because if succes-
sive generations of snakes use the same
“traditional sites” for nesting, any distur-
bance to those sites could be a major
problem. The research also tells us that
these small creatures, with brains about
the size of a pea, can remember the exact
location of their birth site for many
months or years, and find their way back
when it’s time to reproduce. Also, the dis-

covery of “traditional knowledge” in
snakes casts yet more doubt on the belief
that culture belongs only to humans.

The University of Sydney
20 February 2007

Dogs Sterilized To Save 
Endangered Turtles

Stray dogs are being sterilized to protect
many thousands of endangered Olive
Ridley Sea Turtles (Lepidochelys olivacea)
that nest on beaches in Orissa (India)
every winter. Dogs destroy nests and kill
many baby turtles each year. At least 22
dogs were sterilized over the weekend at
the Devi River mouth, one of the three
sites where the turtles come. Amala
Akkineni, of the Hyderabad-based envi-
ronmental group Blue Cross said: “One
pair of dogs gives rise to 2,000 in their
lifetime. The operation will reduce the
number of dogs in these areas, reducing
the future destruction of turtle nests.”

Blue Cross is conducting the sterili-
zation program in collaboration with the
Department of Fisheries and Animal
Resources Development and some
NGOs. Said Amala: “We will sterilize at
least 2,500 dogs in the next six months
in all three nesting sites to save turtle eggs
and hatchlings. We will also provide
training to 15 veterinary doctors to carry
out the task.”

Until five years ago, the sea sur-
rounded two tiny islands, where turtles
come for mass nesting. As a result, no
animal could reach the islands to destroy
the eggs. At least half a million turtles lay
eggs on these two islands. Since 2002,
however, the islands have become acces-
sible from the neighboring Wheeler
Island due to erosion.

Animalconcerns.org
30 January 2007

Snake Found in Hawaii
A worker at Hilo Harbor found and
killed a Chequered Keelback Snake
(Xenochrophis piscator), a species that is
widely distributed in Asia and the East
Indies. These non-venomous aquatic
snakes are not usually considered to be
pets. The carcass was flown to Oahu,
where a specialist from the Bishop
Museum identified the snake. Snakes are
illegal in Hawaii, where no natural means
of control occur and many native species
are potentially vulnerable to introduced
predators. Officials are concerned that
invasive species can significantly hurt
Hawaiian ecosystems.

TheHawaiiChannel.com
30 January 2007

American Crocodile Downlisted 
by U.S. Government Reclassified
from Endangered to Threatened

The U.S. Fish and Wildlife Service
announced Tuesday that recovery efforts
are making it possible to reclassify the
American Crocodile (Crocodylus acutus)
in Florida from endangered to threatened
under the Endangered Species Act.
“American Crocodiles were a part of
Florida’s history for hundreds of years
until human activities such as urban
development, agricultural conversion and
overhunting decimated their popula-
tions,” said Sam D. Hamilton, the ser-
vice’s southeast regional director.
“However, in the past 30 years, we have
made great strides in protecting this
species and conserving its habitat. Today
we can celebrate their comeback as a
result of the recovery efforts by numerous
dedicated professionals who are helping
sustain a vital part of Florida’s natural and
cultural history.”

IGUANA  •  VOLUME 14, NUMBER 2  •  JUNE 2007 133NEWSBRIEFS

Female Australian Keelback Snakes
(Tropidonophis mairii) return to the same area
where they were hatched. So, many snakes
probably lay their own eggs in the same nest
from which they themselves hatched.

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A Chequered Keelback Snake (Xenochrophis
piscator), a species that is widely distributed
in Asia and the East Indies, was found and
killed in Hilo Harbor.

Stray dogs are being sterilized to protect
many thousands of endangered Olive Ridley
Sea Turtles (Lepidochelys olivacea) that nest on
beaches in Orissa, India.

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The service’s final reclassification
decision comes after the completion of its
five-year review required under the ESA
for all endangered and threatened species.
An endangered species is defined as being
in danger of extinction within the fore-
seeable future. A threatened classification
means a species could become endan-
gered. Reclassifying a species from
endangered to the less-critical threatened
designation is often reflective of recovery
efforts reducing imminent threats and
allowing populations to increase.

The American Crocodile is being
reclassified in southern Florida, its only
habitat within the U.S. This crocodilian
will remain endangered in other coun-
tries, including Belize, Colombia, Costa
Rica, Cuba, Dominican Republic,
Ecuador, El Salvador, Guatemala, Haiti,
Honduras, Jamaica, Nicaragua, Mexico,
Panama, Peru, and Venezuela. The
American Crocodile in Florida was orig-
inally listed as an endangered species in
1975. Their numbers in Florida have
grown to an estimated 1,400–2,000, not
including hatchlings.

The species is one of two native
crocodilians, the other being the
American Alligator (Alligator mississippi-
ensis), that are known to frequent the
U.S. It can be distinguished from the
American Alligator by a relatively narrow,
more pointed snout and by an indenta-
tion in the upper jaw that leaves the
fourth tooth of the lower jaw exposed
when the mouth is closed. In order to
reclassify the American Crocodile from
endangered to threatened, the recovery
plan requires a sustained breeding popu-

lation of 60 females. About 95 percent of
the remaining American Crocodile habi-
tat in southern Florida has been acquired
by federal, state, and county agencies.
These protected areas should allow the
population to expand and could provide
additional nesting opportunities.

Miami, Florida

Herpetologists Honored for
Contributions to Conservation

The Florida Chapter of The Wildlife
Society (FLTWS) announced the win-
ners of the first annual Paul Moler
Herpetological Conservation Award. The
recipients, Mark Bailey, Kurt Buhlmann,
Jeff Holmes, and Joe Mitchell, were
selected for producing the new Partners
for Amphibian and Reptile Conservation
publication, “Habitat Management
Guidelines for Amphibians and Reptiles
of the Southeastern United States.”
Featuring detailed, yet easy-to-under-
stand ideas and methods to help
landowners improve the conservation
value of their land, the book has received
excellent reviews from land managers
and conservation professionals across the
region. The Guidelines effectively cover
the wide variety of habitats and the
diverse herpetofauna of the southeastern
United States, both with text and exqui-
site photography. The book is available to
the public and can be ordered at
www.parcplace.org.

The conservation award was pre-
sented during this year’s annual meeting
of the FLTWS, 11–13 April 2007, in St.
Petersburg, Florida. The award was estab-
lished in honor of one of Florida’s preem-
inent herpetologists, Paul Moler, who
retired in 2006 after 29 years of service
with the Florida Fish and Wildlife
Conservation Commission. “I am espe-
cially gratified to see this first
Herpetological Conservation Award go
to the authors of PARC’s outstanding
southeastern Habitat Management
Guidelines,” Moler said upon hearing
the announcement. The FLTWS is made
up of over 300 wildlife professionals ded-
icated to sustainable management of
wildlife resources and their habitats in

Florida. For more information about the
society, visit www.fltws.org.

Dinosaurs and Birds
A few years ago, Michael Crichton wrote
a highly successful and purely speculative
book titled Jurassic Park about extracting
DNA from dinosaurs. Both the book
and the subsequent movie were huge suc-
cesses. Now, Crichton’s imagination has
become reality (although, thankfully, not
the recreation of living animals using
frog-DNA splices).

Scientists have long considered birds
to be the closest living relatives of
dinosaurs. This was based on bone char-
acteristics, because no soft tissue had sur-
vived to confirm the link. Now, protein
extracted from a 68-million-year-old
Tyrannosaurus rex has provided convinc-
ing data. “It’s the first molecular evidence
of this link between birds and dinosaurs,”
said John Asara, a Harvard Medical
School researcher, whose results were
published in the journal Science.

In 2005, Mary Higby Schweitzer of
North Carolina State University found
blood vessels and cells in a T. rex bone
from the fossil-rich Hell Creek
Formation in Montana. In another
Science article, Schweitzer reported that
extracts of that bone reacted with anti-
bodies to chicken collagen, suggesting
the presence of birdlike proteins in
dinosaurs.

134 IGUANA  •  VOLUME 14, NUMBER 2  •  JUNE 2007 NEWSBRIEFS

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The American Crocodile (Crocodylus acutus)
in Florida is being reclassified from endan-
gered to threatened under the Endangered
Species Act.

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The paleontologist Robert T. Bakker once
referred to Tyrannosaurus rex as a “thunder-
chicken from hell.” New evidence provides
strong support for his once controversial
ideas.




