Striped legless lizard  (Delma impar)

Classified as Vulnerable (VU) on the IUCN Red List (1).

Legless lizards, sometimes referred to as ‘snake-lizards’ (5), closely resemble snakes but are distinguishable by the visible ear openings and by greatly reduced hind limbs, which are visible as small flaps (6). A cryptic and difficult to identify species (3), the striped legless lizard varies in colour (7), but is typically light brown with dark brown or blackish stripes running the length of the body (6) (7) (8), although, these stripes can be pale or even absent in some individuals (9). The underside is generally white, cream or pinkish in colour (8), and the head is slightly darker than the body (10).

The striped legless lizard is very slender, only slightly thicker than a pencil (6), with a tail twice the length of the body (2). The tip or whole length of the tail can be voluntarily shed to escape predators (7) (11), and when distressed, this lizard can also emit a high-pitched squeak (12). Male and female striped legless lizards are almost identical in appearance; however, the male may have small ‘spurs’ under each hind limb flap (2). Hatchlings lack the distinctive stripes of adults, but have a characteristic dark brown or black head which may be intended to deter predators by mimicking the highly poisonous eastern brown snake (Pseudonaja textilis) (11).

The striped legless lizard is endemic to south-eastern Australia (5) (13), where it occurs in Victoria, the Australian Capital Territory and parts of New South Wales (13). Its distribution is patchy and poorly documented (4) (5) (6), but substantial range contraction is believed to have occurred over the past 100 years (8).

The striped legless lizard occurs primarily in relatively undisturbed lowland native grasslands dominated by tussock-forming grasses, such as kangaroo grass (Themeda triandra) (6) (7) (8). Originally thought to be confined exclusively to this habitat, the striped legless lizard has now been recorded in some areas which are degraded (8), or dominated by non-native species (2) (4).

Little is known about the striped legless lizard’s biology (8). It is thought to prey selectively on invertebrates measuring one to three centimetres in length (7) (8) (15), such as caterpillars (7), spiders and crickets (13), and its predators are assumed to include snakes, raptors, and other lizards (2). While it is believed to be diurnal (6), moving up to 20 metres in one day (2), the striped legless lizard is often under cover (6)(2), and rarely basks in open areas (12).

The average lifespan of this species is estimated at ten years, with males reaching sexual maturity at two to three years and females at three to four years (2). Little is known about reproduction other than that two eggs are laid in December or January and hatch 35 to 60 days later (2). This lizard appears most active in November and December, a pattern believed to be related to reproductive activity (4). The rest of the winter is thought to be spent underground or beneath rocks and logs (9).

The primary threat to the striped legless lizard is the loss or modification of its grassland habitat (5). Lowland native grasslands are the most threatened ecosystem in Australia, with a staggering 99 percent lost to urban and industrial development and agriculture (2) (8) (14). As a result, the species’ range has decreased dramatically (8), with the remaining populations thought to be small and isolated as a result of habitat fragmentation (2). By 1995, less than 1,000 individuals were recorded across 90 sites, although researchers are hopeful that undetected populations exist (3).

Altered fire regimes may also pose a threat, potentially increasing predation risk, due to loss of cover, or causing direct death; however, the extent of this risk is unknown (2). Other possible threats include rock removal, weed invasion, predation from introduced animals, such as cats and foxes (2) (9), persecution due to their resemblance to snakes, and collection for pets (6).

The striped legless lizard is listed as Vulnerable in Australia under Schedule 1 of the Environment Protection and Biodiversity Conservation Act (1999) (8), meaning that permission must be obtained from the government for any activity which may impact on the species (2). The striped legless lizard is also listed as Vulnerable under regional legislation, including the Flora and Fauna Guarantee Act (1988) in Victoria, the Threatened Species Conservation Act (1995) in New South Wales, and the Nature Conservation Act (1980) in the Australian Capital Territory (4), and it is considered Endangered in South Australia (12).

A National Species Action Plan was devised in 1999, the main aim being the maintenance of long-term, viable, wild populations. Specific conservation objectives include increasing understanding of the species, establishing a series of reserves and managed areas, increasing community awareness, and using captive populations to support research and education (4). Regional Action Plans are also in place in Victoria (6), the Australian Capital Territory (7) and New South Wales (9). In 1998, Melbourne Zoo successfully bred the striped legless lizard in captivity for the first time, and captive-bred individuals have now been released into the Organ Pipes National Park (6).

Large-scale conservation of the striped legless lizard requires conservation of its lowland native grassland habitat, and thus this species’ National Action Plan is linked to the Action Plan for temperate grassland (7). Conservation of grassland habitat will also benefit other threatened species such as the bush stone-curlew (Burhinus grallarius) and the tessellated gecko (Diplodactylus tessellates) (16).

View information on this species at the UNEP World Conservation Monitoring Centre.