(1)Lizards in Taiwan and around the world
Despite the abundance of lizards in Taiwan, only five families of all species in the world are represented: the Agamidae, Gekkonidae, Lacertidae, Scinidae and Anguidae. The following table summarizes the hierarchical classification of lizards in the world:
From the systematic standpoint, snakes (Serpentes) evolved from a branch of lizards.

(2) Are lizards poisonous in Taiwan?
Before we discuss whether lizards in Taiwan are poisonous like snakes, let’s look at the known types of poisonous lizards in the world. Aside from the Heloderma lizards of North and Latin Americas, the majority of lizards are non-venomous. There are no Helodermas among the indigenous species in Taiwan; therefore none of the lizards in Taiwan is venomous.
In the previous article about medicinal use of lizards, it was mentioned that venom from the Heloderma can be used to lower blood pressure and treatment of diabetes and some cancers. Although Helodermas are indeed venomous, their potency is nowhere near snake venom. An interesting example is the Komodo Dragons of Indonesia: their saliva contains bacteria that could cause serious putrefaction of wounds. However, their saliva is not venomous per se; the damage is caused by bacterial infection, not poison. Nevertheless, numerous records of mortality caused by the bites of a Komodo Dragon necessitate research into the lethality of its saliva.

(3) Do lizards in Taiwan make sounds?
Excluding some monitor lizards that hiss when they feel threatened, or the grunt sounds made by some lizards during fights, geckos are the only species of lizards that actually make sounds. Lizards of the Gekkonidae make calls for a variety of purposes, such as establishing a social hierarchy, making territorial claims and mating communications. Like frogs, geckos will also call out for no reasons whatsoever when nightfall comes. However, not all Gekkonidae lizards make sounds. Geckos comprise a large portion of lizards in Taiwan, and the ubiquitous house geckos are the most common calling lizards. These lizards not only call out at nights, during the daytime, they also hide in the shades and emit loud “zhe zhe zhe zhe” like sounds. Traditional Taiwanese folklore believed that “only lizards in the south call; those in the north don’t.” Some suggested that this was based on geographical segregation caused by natural barriers like the Da-An River. In fact, this is a misconception mostly attributed to the difficulty of indentifying the many species of geckos in Taiwan. Without proper training, one would have a hard time noticing the subtle differences in their features. An example is the similarity between the common house gecko and the Bowring’s gecko. The house gecko prefers hot climates; therefore it thrives mostly in Southern Taiwan, whereas the Bowring gecko prefers the more temperate climates of the North. Because house geckos emit very loud calls, the locals mistook them as “only the Southern lizards make calls.” Nowadays with advances in transportation, people can now migrate frequently between Northern and Southern Taiwan. As a result, the house geckos, who like to reside in human dwellings and furniture, gradually spread from the South to the North, and can be heard all island wide now.

(4) Endemic lizards of Taiwan
Lizard species that are endemic to Taiwan are defined as species that have formed stable breeding populations that can only be found on Taiwan, and exist nowhere else in the world. Therefore, any species that are endemic are treated as national treasures. On the other hand, a new species that has been discovered in Taiwan could be a record species, one that has already been documented somewhere else in the world and is introduced to Taiwan through various methods. It could also be a species that was already present, but was not discovered until recently because it was so well hidden. Therefore, a record species is different from an endemic species.
Being an island country surrounded by oceans, the isolated terrain of Taiwan prevents genetic exchanges between lizards, and thus the birth of a new lizard species does not occur as often as in free-roaming animals like flying insects or birds. There are 13 endemic species in Taiwan, occupying about 40.6% of all lizard species in Taiwan. The percentage reaches 48%, nearly half of all the species in Taiwan, if three endemic sub-species are also accounted for. The high diversity and percentage of endemics species is rare among vertebrates in Taiwan.
Currently, endemic species of Taiwan’s lizards include the Formosan Smooth Skink, Taiwan Alpine Skink, Kikuchi's Gecko, Yami's Scaly-toed Gecko, Formosan Grass Lizard, Hsueshan's Grass Lizard, Sauter's Grass Lizard, Stejneger's Grass Lizard, Short-legged Japalura, Lue's Japalura, Maki's Japalura, Swinhoe's Japalura and the Formosan Glass Lizard. The three endemic sub species are the White-spotted Chinese Skink, Formosan Chinese Skink and the Yellow-mouthed Japalura.

(5) Foreign lizards in Taiwan
In contrast with the endemic species, foreign lizards are “invasive” species that are not naturally evolved or geographically segregated in Taiwan, but rather were introduced by humans, either deliberately or inadvertently, and have adapted to the environment of Taiwan and formed stable breeding populations. The most prominent example is the green iguana. This species of lizard is often hunted for food in foreign countries, and its numbers are dwindling to the point of extinction. The bright coloration of a juvenile green iguana makes it a popular pet for the public, and was imported in large numbers by Taiwan’s pet merchants. In the days of inadequate conservation-related laws, these now-protected lizards were imported illegally by unlawful merchants, hoping to make profits by selling to lizard fans in Taiwan. However, as these animals mature, they grow huge and become hard to maintain, requiring lots of space and monetary efforts. They could even become dangerous if they become too big. Lizard fans with a conscience will seek help from relevant organizations by donating to conservation agencies or museums for research; however, those who do not (sadly, the majority) will irresponsibly abandon them in the wild. Usually, a foreign species will not survive easily in a foreign environment, requiring specialized equipment (aquariums, incubators, etc) to regulate its temperature and humidity, in order to stay alive. They will most like perish if left in the wild. However, green iguanas were able to adapt quickly to Taiwan’s environment once they were abandoned, and quickly formed stable breeding populations, threatening the stability of local species. This is resulted in a strange phenomenon: a protected species that is invasive in Taiwan.
The earliest record of the foreign lizard species in Taiwan was the Common Sun Skink (Eutropis multifasciata), first discovered in Kaohsiung County in 1992. These lizards were thought to have been accidentally introduced together with the importation of logs from the Indonesian island of Java. A more recent record was the Brown Anole (Anolis sagrei) found in the nursery patches of Sanjiepu, Chiayi County. These lizards are native to Cuba, the Bahamas and nearby islands in the Caribbean, and juveniles were discovered by researchers as early as 1998. In just two years the populations become stable, and an aggressive invasive species was born. However, there seem to be no signs of expansion in its distribution in recent years, although its effects on the local lizard species (especially the Agamidae) have yet to be studied thoroughly.
Whether or not a pet animal like the green iguana can be considered foreign is still highly debated. After all, it may be too early to call any protected species foreign, whether they are imported for pets or smuggled illegally from abroad. Regardless, the invasion by these foreign species will certainly threaten the local species, especially those that are endemic to Taiwan. How to control the influence of these animals on the environments is an issue that needs to be addressed quickly.
 

(6) Protected lizards in Taiwan
The issue of conservation is global, and Taiwan faces the same problems encountered by other countries in the world. Problems that include: destruction of habitats, excessive cultivation and deforestation of mountainous areas, human over-population, over-urbanization, road construction, use of chemicals and their emissions, and global warming. In order to raise awareness of the above issues, the public must be educated so that they can identify the issues at heart and contribute to conservation. Moreover, the government should intervene actively and set up control measures. In recent years the designation of conservation zones and related areas has been given considerable attention by the authorities; the drive to push conservation forward must continue, in order bring a better future for Taiwan and the world!
According to the newly published list of Taiwan’s conserved species by the Council of Agriculture, currently there are 7 protected lizard species in Taiwan, listed in the following table:

National Museum of Natural Science