Interior Blind Snake (Anilios endoterus)

Conservation status

New South Wales, Biodiversity Conservation Act 2016: Endangered.

Breeding season

The Interior Blind Snake is an egg-laying species with no documented month-specific breeding cycle. Adults are mostly underground but may be surface active at night, especially after heavy rain, so plan clearing as a potential risk in every month.

Reproductive mode: Oviparous, eggs are laid.

Clutch size: 1 to 34 eggs, with an average of 13, recorded for Australian blind snakes generally. This is not confirmed for the Interior Blind Snake.

Incubation: Not recorded.

Size at hatching: Not recorded.

Age at maturity: Not recorded.

Nest or egg sites: Not recorded for this species. Blind snakes generally use protected subterranean ground features, including loose soil, termite nests and spaces beneath rocks, logs and leaf litter.

Breeding frequency: Not recorded.

Confirm timing locally using rainfall and temperature records, because surface activity is reported after heavy rain but species-specific breeding and seasonal data are unavailable.

• Mating: Mating has not been documented by month for this species. Treat mating as possible in any month until local survey or project records show otherwise.
• Gravid females: The documents do not report gravid females or the months when females carry eggs. Inspect and manage subterranean habitat year round because females may be below ground during earthworks.
• Egg laying: Egg-laying months and nest sites are not recorded. Do not assume a low-risk season for soil, termite nests, rocks, logs or leaf litter that may provide protected egg-laying habitat.
• Incubation: Incubation length and the months when eggs remain below ground are not recorded. Treat eggs as potentially present in suitable subterranean habitat in any month.
• Hatchlings: Hatching and juvenile emergence have not been documented by month. Young may be below ground and difficult to detect, so retain suitable soil and ground-cover refuges throughout the year.
• Active period: The species is mostly subterranean but may forage above ground at night, including after heavy rain. No seasonal activity peak is reported, so surface activity should be treated as possible in every month.
• Highest clearing risk: There is no documented low-risk month. Clearing can disturb underground animals, eggs, young and shelter habitat, while night activity may increase after heavy rain.

Identification

The Interior Blind Snake is difficult to detect because it spends most of its time underground. Identification should be based on a combination of body colour, scale counts, snout shape and locality, rather than appearance alone.

This is a dark brown or reddish-brown, moderately slender snake with a paler snout and a white or cream underside. The body has smooth, tight-fitting, shiny scales of similar size. The eyes are vestigial and appear as small dark spots beneath the head scales. They are sensitive to light but do not function as normal, prominent snake eyes.

The snout is weakly trilobed when viewed from above and bluntly angular in profile. The mouth is small and positioned beneath the overhanging snout. The tail is short and ends in a small spur, which assists anchorage and movement through soil.

Typical length: Approximately 25 cm.

Maximum length: Approximately 40 cm.

Midbody scale rows: 22.

Ventral scales: 406 to 438.

Identification: Distinguishing features

The supplied diagnosis identifies the Interior Blind Snake by its dark colour, angular snout, 22 midbody scale rows and nasal cleft proceeding from the preocular. It is most similar to Anilios hamatus, but has a wider rostral scale and more than 400 ventral scales, whereas A. hamatus has fewer than 400 ventrals.

Several former scientific names occur in older survey records, including Typhlops endoterus, Typhlops leonhardii, Ramphotyphlops endoterus, Typhlina endotera and Austrotyphlops endoterus. Records under these names should be checked before treating them as separate taxa.

• Do not rely on the common name or a photograph alone when separating this species from other Australian Anilios.
• Record scale counts and snout characters where handling is authorised and safe.
• Use locality and habitat information with morphology because Australian blind snakes are cryptic, similar in appearance and difficult to observe.

Identification: Field signs and detection

There are no species-specific tracks, scats, calls, nests, sloughs or eyeshine described in the supplied documents. The main field indication is a live snake encountered in loose soil, beneath ground cover, in a termite nest or on the surface at night.

Individuals have been observed above ground at night while foraging and after heavy rain. Because the species is subterranean and occurs at low densities, absence during a visual search does not demonstrate absence from a work area.

• Inspect loose soil beneath rocks, logs and leaf litter during authorised searches.
• Give particular attention to nocturnal searches after heavy rain, when surface activity may increase.
• Treat any small, worm-like blind snake from suitable habitat as a potential Interior Blind Snake until it has been identified by a suitably qualified person.

Distribution: National range

The Interior Blind Snake has a broad but discontinuous inland Australian range. The supplied documents provide state-level records and several named New South Wales localities, but do not define its distribution by IBRA bioregion or provide a national population estimate.

The species is recorded from Western Australia, the Northern Territory, South Australia, Queensland and New South Wales. Its type locality is Hermannsburg in the Northern Territory.

It is associated with central Australian arid and semi-arid regions. The supplied sources do not identify the relevant IBRA bioregions or set a documented elevation limit.

• Western Australia.
• Northern Territory.
• South Australia.
• Queensland.
• New South Wales.

Distribution: Known New South Wales localities

The species was not recorded in New South Wales until surveys at Mutawintji National Park in October 1994, January 1995, April 1995, October 1995 and November 1996. Small numbers have also been recorded at Sturt National Park, Pooncarie and Toorale National Park.

These records indicate important New South Wales occurrences, but the supplied documents do not establish that these sites are national strongholds or separate subpopulations.

Estimated share of national population in NSW: Less than 10%.

Named NSW locations: Mutawintji National Park, Sturt National Park, Pooncarie and Toorale National Park.

Distribution: Population information

The species is described as difficult to detect because of its subterranean habits, low densities and cryptic appearance. The supplied documents do not provide a national population estimate, density estimate, generation length or population trend.

In New South Wales, populations are described as small and isolated. Reduced numbers may increase susceptibility to genetic drift and to catastrophic events.

National population size: Not reported in the supplied documents.

Population trend: Not reported in the supplied documents.

NSW population structure: Small and isolated populations are reported.

Habitat: Habitat types

The Interior Blind Snake is a terrestrial, subterranean species of arid and semi-arid inland environments. Habitat assessment should include the soil profile and ground cover, not only the vegetation present at the site.

The species is associated with sandy areas within grassland, shrubland and spinifex communities. It may live underground in loose soil, in termite nests and beneath rocks, logs and leaf litter.

The supplied documents do not provide a species-specific elevation range or a quantified climate boundary. The documented climate setting is arid to semi-arid central Australia.

• Arid and semi-arid sandy areas.
• Grasslands, including areas with Triodia spinifex.
• Shrublands.
• Spinifex communities.
• Loose soil beneath rocks, logs and leaf litter.
• Termite nests and associated subterranean soil.

Habitat: Structural features

Important site features include loose, penetrable soil, termite nests, soil-surface rocks, fallen logs, leaf litter, understorey shrubs and grassland structure. The New South Wales conservation actions specifically recommend retaining grasslands through the full cycle from seed set to tussock formation.

Soil compaction from livestock and feral goats is identified as a threat in New South Wales. This makes undisturbed soil structure an important habitat attribute during site assessment and construction planning.

• Retain soil-surface rocks and exfoliating rocks.
• Retain fallen logs, especially logs embedded in the soil.
• Retain stick and leaf litter.
• Retain understorey shrubs and regenerating grassland.
• Maintain Triodia where it occurs.
• Avoid unnecessary soil compaction and disturbance.

Foraging habitat: Diet and feeding sites

The Interior Blind Snake feeds mainly on ants and searches for prey in soil and underground spaces. Its feeding habitat is therefore closely linked to loose soil, termite-associated areas and ground cover.

The documented diet is mainly ants. The species forages underground and may emerge at night to forage above ground. Surface activity has also been observed after heavy rain.

The supplied documents do not identify particular ant species, termite species, food plants or a measured foraging range.

Main prey: Ants.

Foraging period: Mainly underground, with nocturnal surface foraging recorded.

Foraging range: Not reported in the supplied documents.

• Protect loose soil and subterranean access beneath rocks, logs and leaf litter.
• Retain termite nests and associated soil where they occur in suitable habitat.
• Schedule nocturnal fauna searches after heavy rain where survey conditions and approvals allow.
• Do not assume that a cleared patch is unused because no snake is seen on the surface.

Breeding habitat: Breeding biology

The Interior Blind Snake lays eggs, but species-specific information on mating, nesting sites, incubation and juvenile development is limited. The available clutch information is for Australian blind snakes generally.

The species is oviparous. The supplied documents do not give a breeding season, incubation period, age at maturity, lifespan or species-specific nesting site.

Australian blind snakes have been recorded with clutches of 1 to 34 eggs, with an average of 13. This group-level information should not be treated as a confirmed clutch size for every Interior Blind Snake population.

Breeding mode: Oviparous, eggs are laid.

Breeding season: Not reported in the supplied documents.

Clutch size: Australian blind snakes: 1 to 34 eggs, average 13.

Gestation: Not applicable to an egg-laying species.

Incubation: Not reported in the supplied documents.

Age at maturity: Not reported in the supplied documents.

Lifespan: Not reported in the supplied documents.

Breeding habitat: Breeding habitat

Specific egg-laying sites are not described. Suitable breeding habitat is expected to include the same protected subterranean conditions used for shelter and foraging, including loose soil, termite nests and ground cover beneath rocks, logs and leaf litter.

For clearing projects, retain connected patches of these features rather than removing isolated rocks, logs, litter and soil structures individually. This is general habitat protection guidance based on the species' documented subterranean ecology, not a confirmed description of its nesting sites.

• Retain loose, uncompacted soil.
• Retain termite nests, embedded logs, rocks and accumulated leaf litter.
• Avoid disturbing suitable ground habitat during periods when eggs or young may be below ground, because the breeding period is not documented.
• Have any blind snake found during earthworks assessed by a qualified fauna handler.

Sheltering habitat: Recorded refuges

The species shelters below ground and uses small soil and ground-cover features rather than trees or large cavities. No refuge dimensions are provided in the supplied documents.

Blind snakes generally occur in underground burrows, termite nests and loose soil beneath rocks, logs and leaf litter. The Interior Blind Snake is described as a cryptic burrowing species that spends most of its time underground.

The supplied documents do not provide burrow diameter, depth, refuge dimensions, home range or distances moved between refuges.

Refuge types: Underground burrows, termite nests, loose soil beneath rocks, logs and leaf litter.

Refuge dimensions: Not reported in the supplied documents.

Tree hollows: No use of tree hollows is reported.

• Inspect beneath rocks, logs and leaf litter during authorised searches.
• Treat termite nests and loose soil patches as potential shelter habitat.
• Retain embedded fallen logs and soil-surface rocks where practicable.
• Avoid stockpiling spoil or compacting soil over suitable ground habitat before fauna clearance.

Sheltering habitat: Detection during works

The species may be encountered during soil disturbance even when no surface signs are present. It may also be found on the surface at night, particularly after heavy rain.

Because it is small, subterranean and difficult to distinguish from related blind snakes, any suspected individual should be handled and identified under the project's fauna management procedures.

• Stop or control machinery around a suspected blind snake until the fauna spotter catcher has assessed it.
• Record the exact location, habitat features and weather conditions for each detection.
• Photograph the head, body pattern and tail spur where this can be done without harming the animal.

Threats: Clearing and ground disturbance

The main project risks arise from removing or compacting the soil and ground cover used for shelter and foraging. Small, isolated populations in New South Wales may be particularly sensitive to local habitat loss and one-off disturbance events.

Habitat degradation and modification threaten the species. Clearing can remove sandy soil, grassland, shrubland, spinifex, termite nests, rocks, logs and leaf litter at the same time.

Soil compaction from livestock and feral goats is specifically identified as a New South Wales threat. Construction traffic, laydown areas, access tracks and repeated vehicle movements can create similar ground-level impacts where they alter soil structure.

• Minimise the footprint of clearing in suitable arid and semi-arid habitat.
• Fence or clearly mark no-go areas containing loose soil, termite nests, embedded logs, rocks or dense ground cover.
• Keep vehicles, compounds and spoil stockpiles off retained habitat.
• Prevent unnecessary soil compaction and reinstate disturbed ground using the approved rehabilitation method.

Threats: Fire, predators and isolation

Inappropriate fire regimes, feral predators such as cats, habitat modification and degradation are documented threats. The supplied documents do not describe a species-specific fire interval, but loss of grassland structure, shrubs, litter, logs and spinifex can reduce the habitat features recommended for retention.

Small and isolated New South Wales populations are more exposed to genetic drift and catastrophic events. Fragmentation can increase the isolation of already small local populations, although a species-specific fragmentation threshold is not provided.

• Retain grassland structure, understorey shrubs, leaf litter, fallen logs and Triodia where practicable.
• Manage fire in accordance with approved ecological fire planning for the site and local community.
• Control or exclude feral cats and other introduced predators where project responsibilities and approvals allow.
• Maintain habitat connections between retained patches where practicable.

Threats: Roads, hydrology and disease

The supplied documents do not identify road mortality, disease or hydrology change as documented species-specific threats. They also do not provide a disease list, road-crossing rate or hydrological threshold.

Any project that changes drainage, inundation, erosion or soil moisture should assess whether it will alter the loose soil and ground-cover conditions used by this subterranean species. This is general impact assessment guidance based on its documented habitat, not a measured response threshold.

• Avoid directing concentrated runoff into retained loose-soil habitat.
• Assess new roads and access tracks for soil compaction and barrier effects.
• Record and report unusual mortality or suspected disease to the relevant wildlife authority.
• Do not infer that the absence of documented road or disease impacts means the risk is absent at a particular site.

Survey methodology: 1. Targeted night searches

Anilios endoterus is a cryptic, subterranean blind snake. It is difficult to detect because it spends most of its time underground, occurs at low densities and resembles other Anilios species. Survey design should therefore combine targeted searches after suitable weather with careful habitat assessment and qualified identification.

Search retained sandy areas in grassland, shrubland and spinifex communities, especially beneath rocks, logs and leaf litter and around termite nests.

Conduct searches at night, when individuals may emerge to forage, and after heavy rain when surface activity has been recorded for blind snakes.

Use experienced herpetologists or fauna spotters who can distinguish Anilios species from other small snakes. Record the search area, start and finish times, weather, rainfall, substrate and all animals detected.

Survey methodology: 2. Daytime habitat and shelter searches

Inspect suitable loose soil beneath rocks, embedded logs, leaf litter and other ground cover before disturbance, using methods that do not unnecessarily destroy shelter sites.

Check termite nests and loose sandy soil where accessible and safe to do so, because blind snakes in this group use underground burrows and termite nests.

Treat a lack of surface detections as inconclusive. The species is subterranean and may remain undetected during a visual search.

Survey methodology: 3. Survey design and detection records

Map sandy grassland, shrubland and spinifex habitat within the proposed clearing area and nearby retained areas before selecting search locations.

Give additional attention to areas with intact leaf litter, understorey shrubs, fallen logs, surface rocks and limited soil compaction, as these features are identified for NSW conservation of the species.

The supplied documents do not provide a species-specific number of nights, hours, trap nights, transect length or survey area. Set effort through the applicable state survey guideline, project approval and advice from the relevant wildlife authority rather than using an invented effort target.

Survey methodology: Minimum effort and reporting

• Complete a habitat assessment and targeted searches before clearing, with extra searches after suitable rain and at night where safe and practicable.
• Use non-destructive searches first and document the limits of access, weather and search conditions.
• Have records checked by a suitably experienced reptile ecologist where identification is uncertain.
• Record every detection with the date, time, location, habitat, photographs where permitted, identification basis and action taken.
• Submit confirmed records and negative survey information, where requested, to the relevant state wildlife database and notify the project environmental officer.
• Check the current survey requirements of the relevant state or territory before finalising the method.

Before habitat disturbance: Avoid and minimise

Plan the work around the species' underground habitat and its NSW conservation needs. The highest practical benefit comes from retaining intact ground cover, loose soil and shelter features, and avoiding unnecessary compaction and grazing impacts.

• Avoid clearing sandy grassland, shrubland and spinifex habitat where the project can be redesigned to retain it.
• Retain connected areas of grassland, spinifex, understorey shrubs, leaf litter, fallen logs and surface rocks.
• Retain embedded logs and rocks that provide cover or connect suitable ground habitat.
• Exclude vehicle movement, stock access and material storage from retained habitat to limit soil compaction.
• Use the smallest practicable disturbance footprint and keep retained habitat connected to nearby suitable areas.

Before habitat disturbance: Approvals and project controls

• Check the current EPBC Act status before works and obtain advice if the project may affect a nationally protected matter.
• Confirm the relevant state or territory approval, permit and fauna handling requirements before capture, relocation or clearing.
• For NSW works, treat the species as endangered and apply the conditions of the applicable approval and threatened species management requirements.
• Prepare a fauna management plan that identifies habitat, survey results, authorised personnel, stop-work triggers, release areas, incident procedures and reporting responsibilities.

Before habitat disturbance: Timing and site preparation

• Stage clearing so that habitat is retained until the pre-clearance inspection and fauna controls are in place.
• Schedule targeted searches after suitable rain and at night where the approved method and site safety plan allow.
• Complete a pre-clearance inspection of the entire disturbance footprint and mark retained rocks, logs, leaf litter, shrubs, spinifex, termite nests and loose-soil areas.
• Install exclusion fencing only where it can prevent entry into the work area without trapping animals, and inspect it before and during works.
• Brief operators and spotter catchers on the species' small size, burrowing behaviour and low detectability.

During habitat disturbance: Daily controls

Clearance must proceed slowly and under the project fauna management plan. Because this snake is small and underground, machinery controls and careful handling of ground features are more reliable than visual observation alone.

• Inspect exclusion fencing, access routes and retained habitat each day before machinery starts.
• Keep machinery within the approved footprint and prevent spoil, fuels and waste from entering retained sandy or vegetated habitat.
• Use staged, low-speed clearing that allows the fauna spotter catcher to inspect exposed soil, shelter features and debris before they are removed.
• Stop or modify work if rain, flooding, poor visibility or unsafe conditions prevent the required inspection.
• Maintain a daily record of personnel, weather, areas cleared, habitat features moved, animals found and incidents.

During habitat disturbance: Spotter catcher and machinery procedures

• Position the fauna spotter catcher where the operator can stop immediately on instruction and where exposed ground and shelter features can be inspected safely.
• Use a progressive clearing sequence that removes vegetation and ground cover in manageable sections before bulk excavation or grading.
• Do not allow the spotter catcher to enter an unsafe machine operating zone or to handle soil, rocks, logs or termite material while machinery is moving.
• Pause work while the spotter catcher checks any small snake, burrow, crack, termite nest or animal movement that could indicate a concealed individual.

During habitat disturbance: Animal finds, habitat features and stop work

• Do not handle the snake unless the person is authorised under the project approval and trained in safe reptile handling.
• If Anilios endoterus is found, stop work in the immediate area, keep people and machinery back, photograph the animal if safe, and obtain an experienced identification.
• Relocate a healthy animal only when authorised, using a short move to nearby retained habitat with suitable loose soil, ground cover and shelter, and record the release location.
• Take an injured animal to an appropriate veterinarian or authorised wildlife carer under the project fauna procedure.
• Handle rocks, logs, leaf litter, termite nests and loose soil as potential habitat features, and place retained features in nearby approved habitat if they must be moved.
• Use a stop-work trigger for an unconfirmed blind snake, repeated detections, an injured animal, a trapped animal or any breach of the approved clearing controls.

After habitat disturbance: Clearance completion checks

Post-clearance checks should confirm that animals and habitat features were not left within the work area and that retained habitat remains protected. The project record should support state reporting and any approval compliance review.

• Inspect the completed clearing footprint, exposed soil, spoil edges, retained ground cover and access tracks for animals before releasing the area to unrestricted construction.
• Check that exclusion fencing, retained logs, rocks, leaf litter, shrubs, spinifex and termite features remain intact in the retained area.
• Document all searches, sightings, relocations, injuries, deaths, unexpected habitat loss and stop-work events.

After habitat disturbance: Monitoring and corrective action

• Monitor retained habitat for disturbance, soil compaction, grazing, fire impacts, weed invasion and loss of ground cover during construction and the approved monitoring period.
• Repeat targeted night searches after suitable rain if required by the fauna management plan, approval or regulator.
• Escalate any new detection, mortality or damage to retained habitat to the project environmental officer and the relevant wildlife authority.
• Repair damaged exclusion fencing and reinstate displaced logs, rocks, leaf litter or other approved habitat features where safe and authorised.

After habitat disturbance: Reporting and offsets

• Submit confirmed records to the relevant state wildlife database and provide required records to the approving authority.
• Report compliance against the fauna management plan, including survey effort, habitat retained, animals handled, release locations and incidents.
• Apply any approved offset or compensatory habitat measure where avoidance and minimisation do not prevent a residual impact.

Rehabilitation actions: Reinstate habitat structure

Rehabilitation should rebuild the ground-level conditions used by this burrowing species. Focus on sandy soil, native grass and spinifex cover, shrubs, leaf litter, logs, rocks and termite-associated microhabitat rather than only replacing canopy vegetation.

• Re-establish native grassland, shrubland or spinifex communities that match the pre-clearing site and surrounding retained habitat.
• Avoid unnecessary soil compaction and retain loose sandy soil where it is suitable for burrowing.
• Replace suitable salvaged logs, rocks and leaf litter in connected patches, including embedded logs where this can be done safely.
• Retain or reinstate understorey shrubs and allow grass to develop through its full cycle from seed set to tussock formation.
• Do not create artificial burrows or move termite nests unless this is designed and approved by a suitably experienced ecologist.

Rehabilitation actions: Manage threats

• Control grazing by livestock and feral goats where it causes soil compaction, loss of grass cover or habitat degradation.
• Manage feral predators, including cats, in accordance with the land manager's approved control programme.
• Use fire planning that maintains suitable grass, spinifex, shrub, litter and shelter conditions and avoids inappropriate fire regimes.
• Control weeds and prevent construction materials, vehicles and stock from entering rehabilitated habitat.

Rehabilitation actions: Measure success

• Inspect rehabilitation for native grass, spinifex, understorey shrubs, leaf litter, suitable rocks and logs, loose soil and connected cover.
• Record soil disturbance, compaction, grazing, fire, weeds and predator activity during the monitoring period set by the approval or rehabilitation plan.
• Use repeat targeted searches after suitable rain and at night, where approved and safe, to assess whether blind snakes or other suitable fauna are using the rehabilitated area.
• Retain monitoring records and submit confirmed detections to the relevant state wildlife database.

Sources

• Genus Anilios, repfocus.dk: https://repfocus.dk/Anilios.html
• Interior blind snake - Wikipedia, en.wikipedia.org: https://en.wikipedia.org/wiki/Interior_blind_snake
• Anilios endoterus (WAITE, 1918) - The Reptile Database, reptile-database.reptarium.cz: https://reptile-database.reptarium.cz/Anilios/endoterus
• Report: Anilios, itis.gov: https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=1116045
• Taxonomy browser Taxonomy Browser () - NCBI - NIH, ncbi.nlm.nih.gov: https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?name=Typhlopoidea