| Citation |
Lwin, K., Neang, T., Phimmachak, S., Stuart, B., Thaksintham, W., Wogan, G., Danaisawat, P., Iskandar, D., Yang, J. & Cai, B. 2019. Gekko gecko. The IUCN Red List of Threatened Species 2019: e.T195309A2378260. https://dx.doi.org/10.2305/IUCN.UK.2019-1.RLTS.T195309A2378260.en. Downloaded on 29 July 2020. |
Description |
JUSTIFICATION
Listed as Least Concern in view of its wide distribution, presumed large population, it occurs in a number of protected areas, has a tolerance of a degree of habitat modification, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category despite recent increases in the extent of exploitation primarily for use in traditional medicine.
RANGE DESCRIPTION
This species is widespread in the Indo-Malayan region (Bauer et al. 2008) from northeast India (Bihar, West Bengal, Assam and Tripura ((Das et al. 2009)) and the Andaman archipelago) and Bangladesh to southern China (Yunnan and Guangxi), and throughout Southeast Asia (Malaysia, Indonesia, the Philippines, Myanmar, Viet Nam, Lao PDR, Cambodia and Thailand) (Das 2010).
In Indonesia records exist from Java, Borneo, Sumatra, the Menatawai Islands (where it is known from Simeulue and Nias but systematic surveys for this species are lacking) and throughout the Lesser Sunda Islands (D.T. Iskandar pers. comm. 2017). Its range limits in China and northern Viet Nam, where it occurs in sympatry with Gekko reevesii, are poorly-understood (Rösler et al. 2011). In China, the distribution of this species, especially its natural distribution, is controversial. Historically this species was considered to occur in tropical and subtropical areas of Guangdong, Guangxi, Guizhou, Tibet, Taiwan, and Yunnan between 200 and 600 m asl. (Yang and Rao 2008). Following the recognition that G. reevesi represents a distinct species by Rösler et al. (2011) its distribution in these areas is unclear, as the extent of sympatry between the two species is unknown, and most records from Nanning (Guangxi) are thought to be animals escaped from farms. The natural distribution of this species in China is thought likely to be limited to the border areas between Guangxi and Viet Nam and between Yunnan and Lao PDR (B. Cai pers. comm. 2018). It has been introduced in Hong Kong.
The species has been reported in the wild in Taiwan on widely separate occasions (in 1923, 1936 and 2008 - Norval et al. 2011) and it is unclear whether this represents a remnant native subpopulation or a consequence of either historical or sporadic anthropogenic introductions as a result of either the medicinal or pet trades (Norval et al. 2011).
In the Philippines, it has been recorded from all islands (up to 1,100 m asl) with the exceptions of Batanes and Babuyanes, and Polillo (Brown and Alcala 1978).
It has been introduced to parts of the United States of America (including Hawaii - Pavia 1999), the West Indies (including several offshore islands in Belize - Stafford and Meyer 1999), and Madagascar (Lever 2003). A recent collection in Porto de Itajai in Brazil, in association with a recently docked container, suggests the possibility that the species already has been or may be introduced to Brazil (Rocha Jr et al. 2015), but no evidence of an established population yet exists. Note that the introduced range is not shown on the map.
DESCRIPTION
This is a common species in most of its range. The species is thought to be less common in urban areas of Thailand than it was historically, although the wild population in this country appears to be stable (N. Panitvong pers. comm. 2017). It remains common and widespread in the Philippines despite a short-lived collection craze 3-6 years ago (R. Brown pers. comm. 2017). It is usually abundant at low elevations in Indonesia (D.T. Iskandar pers. comm. 2017). Global population trends are unknown; while disturbance is increasing the availability of suitable habitat, the species is also subject to increasing harvesting pressure. Dang et al. (2007) estimated a population decline in Viet Nam based on expert opinion of as much as 20% in the period between 1980-2000. It is a dominant species in the Sunderbans (Khan 2013). In China, this species appears to be rare within its distribution, and declining.
HABITAT AND ECOLOGY
This large, nocturnal gecko which can be common in urban and rural areas and, in natural areas, has been observed in lowland and hill dipterocarp forest on the sides of trees and taking refuge in rock cracks during the day. The species thrives in artificial environments. It predates on other geckos, insects, small mammals and small birds. Egg clutches have been observed in a rock crack on a tower karst formation in Perlis, Malaysia, from March through October (Grismer 2011). In Indonesia it favours low elevations and is rarely encountered above 700 m asl. (D.T. Iskandar pers. comm. 2017). It has been reported from Nepal at an elevation of 180 m asl (Wangyal 2012). In Yunnan, it is found on trees (especially large banyan) in tropical and subtropical region with elevation 250-600 m asl. It is also found in rock cracks, or cracks in houses.
In Kolkata (West Bengal, India) it is a very shy animal and wary, hiding itself in the thickest of foliage (Annandale 1907).
THREATS
Its population in China has dramatically declined due to excessive hunting and habitat destruction driven by increasing urbanization. The latter is likely a secondary threat that increases the species susceptibility to collection, as it can otherwise persist in disturbed areas including towns. It has been considered an endangered species in China as a result (Li et al 1996). Recently advertisements were published, especially in Malaysia, Indonesia, and the Philippines, indicating that the consumption of Tokay Gecko tongues and internal organs are a cure for human immunodeficiency virus and cancer (Caillabet 2011, 2013). This has led to these geckos being massively hunted in Southeast Asia for trade, especially in Thailand. The geckos curative powers have since been dismissed as an urban legend in the Philippines, and rates of exploitation are thought to be lower than they were 3-6 years ago as a result (R. Brown pers. comm. 2017).
USE AND TRADE
This species is used extensively in traditional Chinese medicine, with massive hunting for export resulting in dramatic population declines in China (Li et al. 1998). Recently, advertisements were published, especially in Malaysia, Indonesia, and the Philippines, indicating that the consumption of Tokay Gecko tongues and internal organs are a cure for human immunodeficiency virus and cancer (Caillabet 2011, 2013); collection in the Philippines may have subsequently decreased (R. Brown pers. comm. 2017). This has led to these geckos being heavily hunted in Southeast Asia for trade, especially in Thailand. From Thailand alone, around 2.5 million Tokay Geckos are exported to China, Taiwan, Malaysia, and the USA each year (Laoong and Sribundit 2006, Kongbuntad et al. 2016). The species may be of considerable commercial value: export values from Java alone are thought to exceed $1 million annually (Nijman et al. 2012). These authors report that 1.2 million dried specimens are exported from this island annually (Wagner and Dittman 2014). An Indonesian annual export quota of 50,000 specimens (Wagner and Ditman 2014) is believed to apply only to exports for the pet trade (Auliya and Shepherd 2007; M. Auliya pers. comm. 2017). As such, although individual traders are assigned harvest quotas, trade in dried specimens from Indonesia is essentially unregulated.
Auliya and Shepherd (2007) report that the species has been traded for medicinal purposes at least since the 1950s on Java, where there is a belief that it can cure skin diseases. One local collector in East Java, who had been operating for 28 years in 2006. reported that 14,000 animals per week could be collected in the high season (Auliya and Shepherd 2007). Although registered traders in Java are assigned individual harvest quotas, unregistered traders also actively trade this gecko in large numbers, with one reporting that around 1,000 animals a week were collected in the high season (Auliya and Shepherd 2007).
This gecko has long been popular in the international pet trade. As it is widely bred in captivity it is unclear what impact this has on wild subpopulations, however, there is an allotted export quota for live specimens from Indonesia (M. Auliya pers. comm. 2017).
This species is also eaten in Thailand, Viet Nam and likely in Indonesia, and is commonly used in snake wine in Viet Nam (Q.T. Nguyen pers. comm. 2017).
Given that there is a large demand for this species on the Chinese traditional medicine market, this species is made into dried meat and sold on the market among with Gekko reevesii. Since this species appears to be rare in China, large quantities of this species are imported/smuggled into China. Online data shows that over 1,000 specimens were smuggled into China. Besides being using for medicine, this species is often found in the pet trade market due to its large size and colour (B. Cai. pers. comm. 2018).
CONSERVATION ACTIONS
No direct conservation measures are currently needed for this species as a whole, although regulation of trade and enforcement of quotas where these exist would be beneficial. It has been listed in the past as a protected species in Taiwan but there are doubts about its native status on this island; Norval et al. (2011) recommend surveys of sites where the species has been found and phylogenetic analysis to clarify its status in Taiwan. The species occurs in the Barail Wildlife Sanctuary, Assam, India (Das et al. 2009). It is listed as one of 20 nationally protected species in China (Zhang 2008). International trade monitoring is needed, potentially including CITES monitoring to collect data on trade volumes. Research into this geckos taxonomy to clarify and whether or not the gecko is native or introduced (particularly in Java) is needed. |
