All posts by Gerrut Norval

They Simply Don’t Get It: Misguided Conservation Policies in Taiwan Continue to Promote Anole Slaughter


A familiar face – a brown anole male from my study site in southwestern Taiwan.

For the past few years the authorities of Chiayi County, southwestern Taiwan, have paid bounties to citizens for brown anoles they collect. Every year the bounty per lizard has decreased and yet they spend their budget and the brown anole persists. This year is the same – a lower bounty – but with a slight difference; the green iguana is now also on the list. In theory, it would be ideal if the invasive lizards can be exterminated, but in reality, I am convinced, they will fail. The brown anole exists in southwestern and eastern Taiwan, and simply targeting them in one location will simply retard their dispersal to new localities (and even with the bounty in place, their distribution is extending). We recently published the results of a study in which we compared brown anole specimens from southern and eastern Taiwan, and we found that there are some variations, most likely due to adaptations to the local habitats (no surprise there!). What this means is that in Taiwan, if brown anoles can reach (either by natural dispersal or with the help of people) open disturbed habitats, with structures that can be used as perches, they will most likely adapt and establish new populations.

Me with a green iguana (Iguana iguana), that was removed by firefighters from someone’s garden in Chiayi City.

Me with a green iguana (Iguana iguana) that was removed by firefighters from someone’s garden in Chiayi City.


A sun skink (Eutropis multifasciata) from Tainan City, southwestern Taiwan.

And then I wonder why is the brown anole singled out for extermination. Eutropis multifasciata, a relatively large invasive skink, also exists in Chiayi County. Due to its size, it has greater abilities than the brown anole to compete with and prey upon native lizards and arthropods, and yet, they are not on the list. People regard Hemidactylus frenatus, a very common gecko species in urban areas in central and southern Taiwan, as a native species, not realizing that it too is an invasive species.

Hemidactylus frenatus is a very common species in southern Taiwan, where they are often seen near external lights on the walls of buildings.

Hemidactylus frenatus is a very common species in southern Taiwan, where they are often seen near external lights on the walls of buildings.

My honest opinion is they have to accept that just like Hemidactylus frenatus, Anolis sagrei will spread in Taiwan and become a common sight in areas disturbed by humans. They will become (and in many ways already are) part of local ecosystems as competitors, predators and prey. Conservation efforts should thus rather be directed at the re-establishment and conservation of large areas of secondary forests in disturbed lowland areas of Taiwan. This would not only contribute to the conservation of native forest species, but such areas will also function as reservoirs for species like Japalura swinhonis that can compete with Anolis sagrei, as well as being barriers for its spread. People should also be encouraged to be more tolerant towards snakes, in particular non-venomous species such as Lycodon (Dinodon) rufozonatum rufozonatum, Lycodon ruhstrati ruhstrati, and Sibynophis chinensis chinensis, which can prey upon brown anoles. And, finally, an important part in the conservation efforts of native urban wildlife is to develop a better appreciation among the general public of native birds and lizards in urban gardens and parks, and to reduce the impact on these animals by their pets, especially domestic cats (Felis catus), which may prey on them.


Just for interest sake, here is a current list of exotic invasive lizards in Taiwan:

Anolis sagrei

Eutropis multifasciata

Hemidactylus frenatus

Iguana iguana

Lepidactylus lugubris

Physignathus cocincinus

A Tale about Two Tails: No Effect of Having a Regrown Tail on Body Condition

A dorsal view of the brown anole male that I collected on the 19th of July 2002.

A dorsal view of the brown anole male that I collected on the 19th of July 2002.

On the 19th of July, 2002, I collected a brown anole (Anolis sagrei) male from the edge of a rice paddy next to a tarred road in Santzepu, Sheishan District, Chiayi County, Taiwan, as part of a diet and reproductive cycle study. As I removed it from the fine-meshed fishing scoop net, which I used for capturing it, I found that it had two tails. I later found that even though the lizard had no abdominal fat bodies the animal was still in a reproductive state, indicating that it was not only able to regenerate a tail twice, but it could also still meet the energetic demands for reproduction.

This finding prompted our study to attempt to address the question of whether there are differences in the abdominal fat body weights and liver weights of A. sagrei specimens that had suffered tail autonomy and conspecifics that had not.

We were surprised when we found no statistically significant variations in the monthly mean abdominal fat-body weight indices or monthly mean liver weight indexes of lizards that had not experienced caudal autotomy and those that had. We hypothesize that A. sagrei specimens that experienced tail autotomy most likely met the energetic demands for regenerating the lost portion of their tail by foraging more.

Editor’s Note: for more on two-tailed anoles, such as the photo below, type “tail” or “tailed” into the search bar on the right.


A Few Interesting Findings from a Recent Parasitology Study, and a Plea to Other Researchers

The uninformed often view parasites with disdain, disgust, and/or condemnation. These views however ignore the various ecological roles that parasites play. My colleagues and I are some of the lucky few who look at these organisms through ecological lenses and marvel at what we find.

An Anolis sagrei male from Chiayi County, southwestern Taiwan.

An Anolis sagrei male from Chiayi County, southwestern Taiwan.

As part of the ongoing research on the exotic invasive brown anole (Anolis sagrei) populations in Taiwan, we collected and examined some specimens for parasites. In addition to the brown anoles, we also examined specimens of Eutropis longicaudata, Eutropis multifasciata, Japalura polygonata xanthostoma, Japalura swinhonis, Plestiodon elegans, and Sphenomorphus indicus, that were collected opportunistically from Taiwan.

We recently reported on the parasites we recorded in 52 of the 91 lizards examined, and the infected individuals harbored one to three species of parasites. We identified the parasites as Cyrtosomum penneri, Kiricephalus pattoni, Mesocoelium sociale, Meteterakis govindi, Oochoristica chinensis, Oswaldocruzia japalurae, Parapharyngodon maplestonei, Pseudabbreviata yambarensis, Pseudoacanthocephalus bufonis, or Strongyluris calotis. We also recorded an unidentifiable acanthocephalan infective juvenile (cystacanth) and an unidentifiable larva of a cestode (sparganum).

Based on the relatively few parasite species recorded from A. sagrei in Taiwan, compared to the large number of parasites reported from A. sagrei throughout its native and introduced range, it is clear that these lizards have been liberated from many of their parasites.

The nematode, Cyrtosomum penneri, which was introduced into Taiwan along with A. sagrei, was a common parasite in the A. sagrei we examined. None were recorded in any of the other lizard species examined. This is most likely because these nematodes are transmitted from one host to another during copulation and appears to have a fair degree of host specificity, so the spread of C. penneri to native lizard species in Taiwan is suggested to be very unlikely. An interesting conclusion that can be drawn from the presence of C. penneri in specimens from both the southwestern and eastern populations of A. sagrei in Taiwan is that sexually mature lizards were introduced into these localities and that they most likely have a common founder population.

Our study did also confirm that the digenean, Mesocoelium sociale, and the pentastome, Kiricephalus pattoni are acquired parasite of A. sagrei in Taiwan. Unfortunately, although their infections can be expected to be detrimental to the A. sagrei host, their infection frequencies are relatively low in the A. sagrei populations in Taiwan, and thus have no observed significant impact on the population sizes.

Another interesting finding of our study was that even though the nematodes, Pseudabbreviata yambarensis and Strongyluris calotis, are very common in Japalura swinhonis, a species that is very often sympatric with A. sagrei in Taiwan and which also has a very similar diet as A. sagrei, they have not been found in any of the A. sagrei examined to date. This could be a result of an absence of transmission routes that could be specific to J. swinhonis and thus protect introduced species from the native parasites, or the host-specific limitations of the parasites prevent them from adapting to a new hosts, i.e., A. sagrei.

I would like to encourage everyone involved with research to include parasitological studies in their herpetological works to expand our understanding of host-parasite ecology.

And So the Carnage Is Resumed …

A brown anole (Anolis sagrei) male from Santzepu, Chiayi County, southwestern Taiwan.

A brown anole (Anolis sagrei) male from Santzepu, Chiayi County, southwestern Taiwan.

The Taiwanese authorities will once again launch a campaign to try to eradicate the brown anole in southwestern Taiwan. By paying a bounty of N.T.D 3 per collected lizard, they hope to encourage residents to help remove these lizards. They have funds for about 100 000 lizards, but I am afraid that is most likely not enough! The known distribution of this species in southwestern Taiwan is ca. 237 hectares. In my opinion the distribution most likely exceeds that. Those in the know are aware that these lizards can attain great densities. In one study, we found that they can attain densities of about 2900 lizards / ha. So, even if the average density is just 1/10 of that they do not have enough funds.
In addition to that, some religious groups are against the killing of animals and I have found that they do not permit the capture of these lizards on their properties. Even in areas where the capturing of the lizards is permitted, it is difficult to collect all the individuals present. Anolis sagrei that have escaped after being captured tend to flee from a perceived threat at greater distances, which means that such individuals could persist in an area without the collectors being aware of them. These lizards are also opportunistic and can utilize a variety of natural and man-made structures as shelters, many of which would hinder the capture of lizards. In addition to that, some agricultural practices such as the use of greenhouses can act as reservoirs for these lizards. It is thus not surprising that in spite of the large numbers of lizards removed to date, A. sagrei still exists in the southwestern and eastern study site and seems to be expanding its distribution range in Taiwan.

An Anolis sagrei male sheltering in an electrical control unit in an agricultural area in the southwestern Santzepu, Chiayi County, southwestern Taiwan (note the sympatric Hemidactylus frenatus on one of the electrical wires).

An Anolis sagrei male sheltering in an electrical control unit in an agricultural area in the southwestern Santzepu, Chiayi County, southwestern Taiwan (note the sympatric Hemidactylus frenatus on one of the electrical wires).

An Anolis sagrei sheltering in a drainage pipe (right) of a concrete roadside embankment in Santzepu, Chiayi County, southwestern Taiwan.

An Anolis sagrei sheltering in a drainage pipe (right) of a concrete roadside embankment in Santzepu, Chiayi County, southwestern Taiwan.

So my money is on the lizards! Because the distribution of A. sagrei in Taiwan is fairly extensive and the species disperses very easily, the eradication of A. sagrei in Taiwan is impractical. Efforts should rather focus on managing this species.

My opinion is that one of the best ways to do so is by manipulating habitats and making them unsuitable for A. sagrei to inhabit, and so hinder the spread of this species in Taiwan and limit its population growth. The cultivation of crops such as rice (Oryza sativa) and taro (Colocasia esculenta), which are unsuitable habitats for these lizards, should be encouraged in agricultural areas where these lizards are known to occur. Also, since broadleaf forests in Taiwan are likely unsuitable habitats for A. sagrei, greater efforts should be made to re-establish and conserve large areas of broadleaf forests in disturbed lowland areas of Taiwan. This would not only contribute to the conservation of native forest species, but such areas will also function as reservoirs for species like Japalura swinhonis that can compete with A. sagrei, as well as being barriers for its spread.

Please Help Us Make the Sungazer the National Lizard of South Africa

Cordylus giganteus

South Africa has various national wildlife symbols:

National animal – the springbok (Antidorcas marsupialis)

National bird – the blue crane (Anthropoides paradisia)

National fish – the galjoen (Dichistius capensis)

National flower – the king protea (Protea cynaroides)

National tree – real yellowwood (Podocarpus latifolius)

Now, I would like to appeal to Anole Annals readers to help get the sungazer, Smaug giganteus (formerly Cordylus giganteus), formally recognized as South Africa’s national lizard by the Department of Arts and Culture. This would promote the conservation of this species, but by using it as an umbrella species, the conservation of their grassland habitats would also benefit various other organisms. It will only take a few minutes of your time. Just visit and sign the petition at:

The Swinhoe’s tree lizard (Japalura swinhonis) is a common endemic lizard species in Taiwan.

The Swinhoe’s tree lizard (Japalura swinhonis) is a common endemic lizard species in Taiwan.

Wouldn’t it be great if we could get a national lizard nominated for every country?

I nominate the Swinhoe’s tree lizard (Japalura swinhonis) for Taiwan.

Which anoles would you nominate for which countries?

Proud of My “Browns”

Me in uniform – many years, kilograms and grey hair ago.

Me in uniform – many years, kilograms and grey hair ago.

For many years, most units in the South African Defense Force used a plain medium brown uniform, called nutria. Soldiers commonly referred to it as “browns.” A few years before my national service, the defense force started phasing it out, replacing it with the “Soldier 2000” camouflage design. When I was conscripted to serve in the South African Medical Services (SAMS) in 1993, SAMS was the only unit that completely still used the nutria uniforms, and although not as “modern-looking” as the other uniforms, we developed a sense of pride in our “browns.”

I believe the brown anole (Anolis sagrei) needs little introduction to Anole Annals readers. I am very fortunate to have been able to do my research on the invasive population of these lizards in southwestern Taiwan. I have been a naturalist at heart since a very young age, but these lizards were my introduction to the academic side of natural history, and because of my work on them I have made numerous friends and acquaintances. So, naturally they hold a special place in my heart and mind.

A female brown anole (Anolis sagrei) from my study area in Santzepu, Sheishan District, Chiayi County, southwestern Taiwan.

A female brown anole (Anolis sagrei) from my study area in Santzepu, Sheishan District, Chiayi County, southwestern Taiwan.

Unfortunately these feelings brought a sense of guilt within me. I know all too well that they are an invasive species, which has certain impacts on native species. And yet, it is hard not to marvel at them and their ability to overcome the numerous obstacles they face in this foreign habitat.

The other day, while reading the obituary of Henry S. Fitch (1909-2009) in the 2009 issue of Herpetological Review (40[4]: 393-400), the words of Raymond B. Huey suddenly made it all so clear to me. He described an instance in which he left a meeting at which Henry Fitch was a speaker, with a haunting lesson, “We should do science because we love the process, not because we need to love the results.” I believe that for us who work with invasive species, this is also a message. So now, when I see brown anoles, I no longer have to feel guilty when I do not wish they were rather tree lizards (Japalura spp.) or grass lizards (Takydromus spp.). I admire the “browns” and I find the process of learning about their natural history truly fascinating – I love it! I wonder how many other researchers working on invasive anoles share this sentiment?

When You Can Not Get The Results You Expected, Use What You Can Get!

An adult Anolis sagrei male specimen from Santzepu, Sheishan District, Chiayi County, southwestern Taiwan.

An adult Anolis sagrei male specimen from Santzepu, Sheishan District, Chiayi County, southwestern Taiwan.

Field research does not always go the way we plan. My research partners and I were reminded of that in 2004, when we tried to use a mark-and-recapture method to determine the population sizes of brown anoles (Anolis sagrei) in a small betelnut palm (Areca catecha L) plantation in Santzepu, Sheishan District, Chiayi County, southwestern Taiwan. We ended up with too low recapture rates for our estimates. Still all was not lost! Of the lizards we did recapture, we were able to calculate monthly growth rates and monthly growth percentages. The results indicated that at least some individuals experienced active growth throughout the year. Our results also supported the findings of Schoener and Schoener (1978) and Cox et al. (2009) that smaller individuals of both sexes grew faster than larger conspecifics of the same gender, and that males grew faster than females. We also determined that growth rates of both sexes decreased during the peak reproductive period, suggesting that available energy is directed primarily to reproduction and the associated to behavior, and that energy is only directed towards growth once the requirements for reproduction are met.

The experience from this study convinced me again that it is important to collect as much data as possible when conducting field studies – it is hard to predict where it may come in handy at a later stage.

Stowaway – Can You Identify This Unfortunate Traveller?

Anolis sagrei (male) 266

An Anolis sagrei male from my study area in southwestern Taiwan.

Working with the brown anole (Anolis sagrei) is an eye-opener to the ability of some species to disperse far beyond the barriers that limit their natural dispersal potential. Anolis sagrei from Florida managed to reach Taiwan, most likely along with some nursery or agricultural products. They have also managed to reach Singapore, also I suspect along with some nursery products.

unknown snake

Can you identify this snake for us please?

Recently, an instance of a non-anole long-distance traveler came to my attention, and I would like to ask if anyone can help us identify the species involved. A friend told me about a snake that he obtained from someone, who got it from a person who imported wood from South America. Apparently, as the importer was about to start processing the wood he received, the snake slithered out of it. To me, the snake looks like a neotropical whipsnake (Masticophis mentovarius). However, it traveled by ship, meaning it could have gotten onboard at any port where the ship might have stopped. Thanks.

Brown Anole Feeding On Sap

anole annals

Various anole species have been observed feeding on fruit (e.g., Herrel et al. 2004) and nectar (e.g., Colón Archilla 2010). On March 08, 2013 a brown anole (Anolis sagrei) male in my study area joined the growing list of lizards that have been observed feeding on plant sap. In our natural history note we not only describe how he fed on the sap of a banana plant (Musa sapientum), but also provided some notes on its display behavior.

Natural history notes like this usually describe single observations and may seem of minor significance. However, such observations contribute to our understanding of the natural history of the species in question, and can be an inspiration for study areas. And for that reason I encourage everyone to describe observations not only in Internet blogs, but also in journals such as Herpetology Notes and Herpetological Review. That way the information can be shared with a greater readership, and a record is left for generations to come.


NOTE: For those of you who are curious. I also wanted to know what the sap tasted like, so after touching some of it, I licked the tip of my finger. The sap had a very mild bitter taste, not something I would try to market as a soft drink.

There Is Always Something New To Learn: Lizard Eggs Can Survive Flooding

A close-up of the hatchling, un-hatched egg, and the remains of the hatched egg, we recently reported on.

A close-up of the hatchling, un-hatched egg, and the remains of the hatched egg, we recently reported on.

It is interesting that even in fairly well-studied species, we can still find new information from chance observations and carefully planned empirical studies. Recent studies have found that brown anole (Anolis sagrei) females favor nest sites that are quite moist. Losos et al. (2003) also found that the eggs of this species can survive being inundated for up to six hours by seawater. Recently we reported on an observation of brown anole eggs that remained viable after being inundated by fresh water due to heavy rains. The difference between the two conditions is, since seawater is more saline than the content of the eggs, it can be expected that the eggs would lose water, while when exposed to excessive fresh water the water gains will exceed losses, and the eggs will swell.

The observations of other researchers and ours suggest that the eggs of A. sagrei are fairly tolerant to a wide variety of environmental conditions and can remain viable when exposed (for a few hours) to excessively wet conditions. Our observations in Taiwan also reveal that unless washed away or damaged, the eggs of A. sagrei can remain viable during the high rainfall (often as a result of typhoons) of this region.

As Aristotle (384 BC – 322 BC) said, “In all things of nature there is something of the marvelous.” And I would like to encourage everyone to look into their chance observations and to describe them, not only in chat forums, but also in journals as natural history notes. That way the information is not only disseminated, but may also be accessible to a greater audience and for generations to come.

Anoles Feeding On Liquids – Please Help

Anole feeding on nectar. What about sap? Photo by Sparky Leigh.

Good day everyone. I am currently working on a short manuscript about a brown anole that I observed feeding on sap. I am aware that some anoles will feed on nectar (see list below), but I would like to know if anyone has ever observed anoles feeding on sap? If you have any references pertaining to anoles feeding on nectar or sap, and it is not listed below, would you please e-mail it to me at, or at least provide me with the reference so that I can try to obtain it myself. Thank you very much.


P.S. Lizards rule!

References I am aware of:

Campbell, T. and C. Bleazy. 2000. Natural history notes:  Anolis carolinensis (green anole). Nectivory and flower pollination. Herpetological Review 31: 239.

Colón Archilla A.D. 2010. Nectivory in Puerto Rican emerald anoles (Anolis evermanni). IRCF Reptiles and Amphibians 17: 144–145

Echternacht, A.C. and G.P. Gerber. 2000. Anolis conspersus (Grand Cayman Blue throated Anole). Nectivory. Herpetological Review 31:173.

Liner, E.A. 1996. Natural history notes: Anolis carolinensis carolinensis (green anole). Nectar feeding. Herpetological Review 27: 78.

Okochi, I., M. Yoshimura, T. Abe, and H. Suzuki. 2006. High population densities of an exotic lizard, Anolis carolinensis and its possible role as a pollinator in the Ogasawara Islands. Bulletin of the Forestry and Forest Products Research Institute 5: 265–269.

Perry, G. and J. Lazell. 1997. Anolis stratulus (Saddled Anole). Nectivory. Herpetological Review 28:150–151.

Perry, G. and J. Lazell. 2006. Anolis pulchellus (Grass Anole). Nectivory. Herpetological Review 37:218–219.

Rios-Lopez, N. 2004. Anolis stratulus (Saddled Anole). Extrafloral herbivory. Herpetological Review 35:386.

Timmermann, A., B. Dalsgaard, J.M. Olesen, L.H. Andersen, and A.M. Martin Gonzalez. 2008. Anolis aeneus (Grenadian Bush Anole). Anolis richardii (Grenadian Tree Anole). Nectivory/pollination. Herpetological Review 39:84–85.

Valido, A.M. 2006. Anolis allisoni (Allison’s Anole/Cameleon Azul). Nectar feeding. Herpetological Review 37:461.

When The “New World” Meets The “Old World”: Interactions Of Introduced Anoles and Native Agamids In Taiwan

The observations made on the 14th of July, 2002. A – the adult male Japalura swinhonis attempts to prey upon the crickets it can see through the plastic container; B – the Japalura swinhonis moves aside, and an adult male Anolis sagrei takes his place at the plastic container; and C – as the Anolis sagrei attempts to prey on the crickets, which it can see through the plastic, the Japalura swinhonis moves up the trunk of the betel nut palm.

On the 14th of July, 2002, I wanted to test the possibility of using a modified funnel-trap to collect Anolis sagrei. The first lizard to respond to my trap, though, was an adult male of the agamid, Japalura swinhonis, that was attracted by the movements of the crickets in the trap. The J. swinhonis attempted to prey on the prey items for about 30 seconds. When an adult male A. sagrei approached, the J. swinhonis moved up the trunk of the betelnut palm onto which the trap was secured. No further observations were made after the A. sagrei lost interest after about one minute and moved off.

This was to date the only instance I observed in which a J. swinhonis gave way to an A. sagrei, and I am quite convinced that the J. swinhonis actually just lost interest in the possible prey in the trap, and as it moved away the A. sagrei thought he could try his luck. And this is my point concerning A. sagrei in Taiwan.

In my study area in Santzepu, Chiayi County, southwestern Taiwan, J. swinhonis males (mean ± SD = 70.5 ± 8.4 mm) and females (mean ± SD = 58.2 ± 13.9 mm) are substantially larger than A. sagrei (males; mean ± SD = 46.2 ± 9.1 mm; females; mean ± SD = 38.2 ± 5.5 mm). In most other aspects, both species are quite similar; both are diurnal trunk-ground ambush foragers and are very territorial. In a paper I am currently preparing, I compared the diet of these species and found that A. sagrei has a much wider dietary niche breadth than J. swinhonis, and that in areas where J. swinhonis and A. sagrei are sympatric, there is a substantial dietary niche overlap, and competition for prey is very likely.

Although both species are human commensals, J. swinhonis is more shade tolerant, while A. sagrei reaches higher densities in open disturbed habitats. So, my view of A. sagrei in Taiwan is that this species is here to stay, and we have to accept that it is becoming part of local ecosystems. Continue reading When The “New World” Meets The “Old World”: Interactions Of Introduced Anoles and Native Agamids In Taiwan

Is There An Alien Invasion In Taiwan?

The Anolis carolinensis observed in Chiayi County, Taiwan, on the trunk of an Areca catechu.

Currently, the list of exotic invasive herpetofauna in Taiwan is fairly short:

brown anole (Anolis sagrei)

sun skink (Eutropis multifasciata)

common slider (Trachemys scripta elegans)

American bullfrog (Rana catesbeiana)

Asiatic painted frog (Kaloula pulchra pulchra)

Hong Kong whipping frog (Polypedates megacephalus)

But if the list of species permitted in the pet trade in Taiwan is not revised, and drastic steps are not taken to prevent future accidental and/or intentional introductions of exotic invasive amphibians and reptiles, that is sure to change.

There are already anecdotal accounts of green iguanas (Iguana iguana) and water dragons (Physignathus lesueurii) in the wild, and in 2011 we reported on some tokay geckoes (Gekko gecko) that we found in the wild in central western Taiwan. Earlier this year when we reported on a green anole (Anolis carolinensis) that we found in 2002 in a rural area of Chiayi County, southwestern Taiwan, we added another species to the list of species that have been recorded in the wild.

The discovery of these lizards in the wild in Taiwan is alarming. If suitable numbers of these animals are released into the wild, they very likely will establish viable populations in Taiwan.

The Reproductive Cycle Of The Brown Anole In Taiwan

Brown anoles mating.

Most invasive vertebrates have a high reproductive rate, and are able to build up a large population under ideal conditions. A recently published report on the reproductive cycle of the brown anole (Anolis sagrei) in Taiwan highlights this again.

This study demonstrated that the reproductive cycle of the Anolis sagrei population in Taiwan is long and cyclic, and that it is very similar to that of conspecific populations in Belize, Cuba, Florida, and Hawaii.

We found that as in Florida, the females become sexually mature at about 34 mm SVL. As in other studies, we found that Anolis sagrei females produces multiple clutches, consisting of a single egg, throughout most of the year, and that due to sperm storage, are able to produce viable eggs for a few weeks, even in the absence of males.

Unlike in other studies, we found that the males could be sexually mature at a much smaller SVL (ca. 30 mm), and that at least some males with spermatozoa, which could mate, are present throughout the year. The smaller SVL of the males mean a shorter time from hatching to the age at which mating can commence. And even though it is uncertain that such males would be able to compete with larger territorial males, these smaller males would certainly have mating opportunities in the absence of larger males in founder populations.

We found that the hatchlings have a SVL of about 18 mm, and as in other studies, they hatch after a period of about 30 days.

In view of the potential for A. sagrei taking over new territories, to prevent future introductions of this species, we strongly feel that drastic steps are merited.

A Little Worm “Told” Us …

Studying the brown anole (Anolis sagrei) in Taiwan has presented me with numerous new opportunities, one of which is an introduction into parasitology.

A Kiricephalus pattoni nymph under the skin of a female brown anole (Anolis sagrei), collected in southwestern Taiwan.

The first parasites I found in A. sagrei in Taiwan were relatively large worm-like parasites that are often visible as a lump under the skin of the lizard. Unfortunately, my first samples were lost by the person I had sent them to for identification. But luckily, I found some more, and with the assistance of C.R. Bursey and S.R. Goldberg, the parasites were identified as the nymphs of the pentastome, Kiricephalus pattoni. Together we reported A. sagrei as a new host of this parasite in Taiwan (Norval et al., 2009). Continue reading A Little Worm “Told” Us …

And The Carnage Will Continue …

The newspaper article to announce the actions to eradicate brown anoles (Anolis sagrei) in Santzepu, Sheishan District, Chiayi County, Taiwan.

On the 28th of April, 2011, I posted an article here in AA about the actions of the Taiwanese authorities to try and remove Anolis sagrei in Chiayi County. On the 25th of June, 2011, it was announced that they have acquired more funding (they ran out of funds previously) and that they will continue with these actions this year.

The alarming part is how they (whoever wrote the article) mislead the public, who believes in what is said in the newspapers, by providing incorrect information in the article.

They report that in the past two years 127,458 brown anoles were removed, and since the past winter was colder than usual, they believe they can eradicate this species by again paying the public a bounty of N.T.$ 20 (ca. U.S.$ 0.70) for every lizard they collect. I am confident they will run out of funds again, and the brown anole will persist! I am also convinced that something other than conservation is driving these actions. Continue reading And The Carnage Will Continue …

Not All Lizards Attended That Lesson

The Lizard Keeper’s Handbook. p 101

In his book, The Lizard Keeper’s Handbook (1997. Advanced Vivarium Stystems, Inc.), Philippe de Vosjoli explains at length how to select prey items of appropriate sizes to feed to pet lizards. I agree 100% with what he wrote. However, I must say that not all lizards apply these rules under natural conditions (I guess they were absent from class on the day that lesson was taught). Here are some photographs I took of brown anoles and Swinhoe’s tree lizards in my study area that preyed on prey items that most certainly did not fall within the ideal prey size categories. 

 1. An Anolis sagrei male with a large caterpillar.

 2. An Anolis sagrei female with the remains of a grasshopper that she had had in her mouth when we captured her.

 3. A Japalura swinhonis female that rushed in to grab a beetle grub that was exposed when we accidentally knocked over a dead betelnut palm (Areca catecha) in our study area.

 4. A Japalura swinhonis male that captured an adult Clanis bilineata in the secondary forest in our study area.


And I believe that anyone who works with the brown anole (Anolis sagrei) would agree with me that these lizards can do some truly amazing things, as can be seen from the photos above. One of the most mind-boggling things I have found in the stomach contents of some of these lizards are centipedes. On one occasion I found a 43 mm long Chinese red-headed centipede (Scolopendra subspinipes mutilans) in the stomach of a brown anole male (SVL = 54 mm). Not only was the prey almost as long as the body length of the predator, but centipedes are venomous. It takes guts to take on such a meal!




Brown Anoles Also Eat Butterflies And Moths

Here are three photographs I took of brown anoles preying on lepidopterans. In our diet studies lepidopterans were one of the main prey types, although, as can be expected, the larvae outnumbered the adults as prey. Amazingly, the lizards even ate larvae that had hair, which would cause an irritating burning sensation if it comes in contact with your skin.

Never Underestimate The Ability Of The Media To Make A Bad Situation Worse

The brown anole (Anolis sagrei) was discovered in Santzepu, Chiayi County, southwestern Taiwan, in mid 2000, and except for a few academics, most people didn’t seem to notice the existence of this exotic invasive species. That all changed when red fire ants (Solenopsis invicta) were discovered in northern parts of the island in 2003. Suddenly, invasive species became a very hot topic, and the authorities launched various projects to assess and study invasive species in Taiwan. Soon, as could be expected, A. sagrei was also in the news. Continue reading Never Underestimate The Ability Of The Media To Make A Bad Situation Worse