Species Profile

Desert Nightsnake

Scientific Name: Hypsiglena chlorophaea
Other/Previous Names: Night Snake ,Nightsnake ,Hypsiglena torquata
Taxonomy Group: Reptiles
COSEWIC Range: British Columbia
COSEWIC Assessment Date and Status Change: May 2011
COSEWIC Status: Endangered
COSEWIC Status Criteria: B1ab(iii)+2ab(iii)
COSEWIC Reason for Designation:

This nocturnal and secretive snake occurs in arid and semi-arid regions of western North America, reaching its northern distributional limits within seasonally hot interior valleys of south-central British Columbia. Throughout its small Canadian distribution, expanding urban and agricultural developments and their associated infrastructures threaten habitats of the species. Scattered distribution pattern, small population size, and no possibility of rescue contribute to the vulnerability of the species and place it at imminent risk of extirpation.
COSEWIC History of Status Designation: Designated Endangered in May 2001 and May 2011.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2003-06-05

Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.

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Quick Links: | Photo | Description | Distribution and Population | Habitat | Biology | Threats | Protection | Recovery Initiatives | National Recovery Program | Documents

Image of Desert Nightsnake

Desert Nightsnake Photo 1

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Description

The Night Snake is a small snake with dark grey or brown blotches on a light grey or brown back, and a yellowish or white belly. While it is technically venomous, it is a member of the family of “harmless snakes”, which includes most Canadian species of snakes. The Canadian population is identified as the deserticola subspecies of Hypsiglena torquata. (Updated 2017/05/25)

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Distribution and Population

In Canada, the Night Snake is found exclusively in the hot, dry interior of British Columbia; fewer than 20 individuals have been found. The snake’s distribution ranges extensively throughout the southwestern states of the USA, Mexico and parts of Central America to Costa Rica. In general, it is less common than other snakes that occur in the same habitat and more common in southern than northern parts of its range. (Updated 2017/05/25)

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Habitat

Most of the Night Snakes found in British Columbia were in areas with rocks, shrubs and grasses. They show a preference for south facing talus slopes or rock outcrops. (Updated 2017/05/25)

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Biology

Common food items of the species are lizards, squamate eggs, frogs and snakes, although the only recorded food item for a Night Snake in Canada is a neonate rattlesnake. They sometimes burrow in sand to ambush their prey. Hypsiglena torquata is oviparous and lay 3 to 9 eggs in a clutch. Time of nesting is variable and is unknown in Canadian populations. Night Snakes hibernate during the winter, occasionally sharing dens with rattlesnakes. Night Snakes in British Columbia can live at least four to five years. Most aspects of the life history of Night Snakes in general, and the Canadian populations in particular, are not well studied. (Updated 2017/05/25)

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Threats

The Night Snake is threatened by human activities. The preferred habitat in British Columbia is quickly being developed for urbanization, vineyards and orchards, and talus materials are harvested for use in the construction and landscaping industry. In addition to the habitat loss, Night Snakes are also vulnerable to fragmentation of their habitat as it may act as a barrier to dispersal. Finally, Night Snakes are susceptible to being killed on roads. With increased development of their habitat, the incidence of road killed snakes is likely to increase. (Updated 2017/05/25)

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Protection

Federal Protection

The Desert Nightsnake is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.

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Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for the Nightsnake (Hypsiglena torquata) in British Columbia
Status Broader consultation initiated

Name Recovery Strategy for the Western Rattlesnake (Crotalus oreganus), the Great Basin Gophersnake (Pituophis catenifer deserticola) and the Desert Nightsnake (Hypsiglena chlorophaea) in Canada
Status Final posting on SAR registry

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Documents

PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

10 record(s) found.

COSEWIC Status Reports

  • COSEWIC Assessment and Status Report on the Desert Nightsnake (Hypsiglena torquata) in Canada (2011-09-09)

    The Night Snake is a small snake with dark grey or brown blotches on a light grey or brown back, and a yellowish or white belly. While it is technically venomous, it is a member of the family of “harmless snakes”, which includes most Canadian species of snakes. The Canadian population is identified as the deserticola subspecies of Hypsiglena torquata.

Response Statements

  • Response Statement - Desert Nightsnake (2011-12-08)

    This nocturnal and secretive snake occurs in arid and semi-arid regions of western North America, reaching its northern distributional limits within seasonally hot interior valleys of south-central British Columbia. Throughout its small Canadian distribution, expanding urban and agricultural developments and their associated infrastructures threaten habitats of the species. Scattered distribution pattern, small population size, and no possibility of rescue contribute to the vulnerability of the species and place it at imminent risk of extirpation.

Recovery Strategies

  • Recovery Strategy for the Western Rattlesnake (Crotalus oreganus), the Great Basin Gophersnake (Pituophis catenifer deserticola) and the Desert Nightsnake (Hypsiglena chlorophaea) in Canada (2019-09-05)

    The Minister of Environment and Climate Change is the competent minister under SARA for the Western Rattlesnake (Crotalus oreganus), the Great Basin Gophersnake (Pituophis catenifer deserticola) and the Desert Nightsnake (Hypsiglena chlorophaea) and has prepared the federal component of this recovery strategy (Part 1), as per section 37 of SARA. To the extent possible, it has been prepared in cooperation with the Province of British Columbia as per section 39(1) of SARA. SARA section 44 allows the Minister to adopt all or part of an existing plan for the species if it meets the requirements under SARA for content (sub-sections 41(1) or (2)). The Province of British Columbia provided the attached recovery plans for the Snakes of the British Columbia Southern Interior - Western Rattlesnake, Great Basin Gophersnake and Desert Nightsnake (Part 2) as science advice to the jurisdictions responsible for managing the species in British Columbia. It was prepared in cooperation with Environment and Climate Change Canada.

Orders

  • Order Amending Schedule 1 to the Species at Risk Act (volume 146, number 14, 2012) (2012-07-04)

    The purpose of the Order Amending Schedule 1 to the Species at Risk Act is to add 18 species to Schedule 1, the List of Wildlife Species at Risk (the List), and to reclassify 7 listed species, pursuant to subsection 27(1) of SARA. This amendment is made on the recommendation of the Minister of the Environment based on scientific assessments by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and on consultations with governments, Aboriginal peoples, stakeholders and the Canadian public.

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2010 - 2011 (2011-09-09)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”. COSEWIC held two Wildlife Species Assessment Meetings during the past year assessing the status or reviewing the classification of a total of 92 wildlife species.

Permits and Related Agreements

  • Explanation for issuing permit(#SARA-PYR-2008-0071), persuant to the provisions of section 73 of SARA (2008-03-01)

    15 Adult Male Western Rattlesnakes (Crotalus oreganus) and 25 Great Basin Gophersnakes (Pituophis catenifer deserticola) will be surgically implanted with radio-transmitters following approved animal care protocol from the University of Guelph Animal Care Committee and the British Columbia Ministry of Water, Land and Air Protection, and located 3-4 times per week (Between March-Oct 2008 and 2009). Approximately 100 of each of these 4 species, Western Rattlesnakes , Great Basin Gophersnakes, Nightsnakes (Hypsiglena torquata) and Western Skink (Eumeces skiltonianus )(male and female of all ages) will be part of a mark and recapture program. Individuals will have measurements taken following approved animal care protocol and immediately released back into the wild (Between March - Oct 2008 and 2009). This research will (a) identify densities and travel corridors of Western rattlesnakes (threatened) years 1-2 and Great Basin Gophersnakes (threatened) years 1-2. (b) Identify ovipositian sites of Great Basin Gophersnakes (year 2) (c) Determine a population estimate for Nightsnakes (endangered) and Western skink (special concern skinks are a primary diet item of the Nightsnakes and these species co-occur on talus slopes) year 2.
  • Explanation for issuing permit(#SARA-PYR-2010-0127), persuant to the provisions of section 73 of SARA (2010-03-01)

    15 Adult Male Western Rattlesnakes (Crotalus oreganus) and 15 Great Basin Gophersnakes (Pituophis catenifer deserticola) will be surgically implanted with radio-transmitters following approved animal care protocol from the University of Guelph Animal Care Committee and the British Columbia Ministry of Water, Land and Air Protection, and located 3-4 times per week (Between March-Oct 2010 and 2011). Approximately 100 of each of these 4 species, Western Rattlesnakes , Great Basin Gophersnakes, Nightsnakes (Hypsiglena torquata) and Western Skink (Eumeces skiltonianus )(male and female of all ages) will be part of a mark and recapture program. Individuals will have measurements taken following approved animal care protocol and immediately released back into the wild (Between March - Oct 2010 and 2011). This research will (a) identify densities and travel corridors of Western rattlesnakes (threatened) years 1-2 and Great Basin Gophersnakes (threatened) years 1-2. (b) Identify ovipositian sites of Great Basin Gophersnakes (year 2) (c) Determine a population estimate for Nightsnakes (endangered) and Western skink (special concern skinks are a primary diet item of the Nightsnakes and these species co-occur on talus slopes) year 2.
  • Explanation for issuing permit(#SARA-PYR-2010-0147), persuant to the provisions of section 73 of SARA (2010-06-08)

    15 adult male Western Rattlesnakes (Crotalus oreganus) and 15 Great Basin Gophersnakes (Pituophis catenifer deserticola) will be surgically implanted with radio-transmitters following approved animal care protocol from the University of Guelph Animal Care Committee and the British Columbia Ministry of Water, Land and Air Protection, and located 3-4 times per week (Between March-October 2010 and 2011). Approximately 100 of each of these 4 species, Western Rattlesnakes , Great Basin Gophersnakes, Nightsnakes (Hypsiglena torquata) and Western Skink (Eumeces skiltonianus )(male and female of all ages) will be part of a mark and recapture program. Individuals will have measurements taken following approved animal care protocol and immediately released back into the wild (between March - October 2010 and 2011). This research will (a) identify densities and travel corridors of Western rattlesnakes (threatened) years 1-2 and Great Basin Gophersnakes (threatened) years 1-2. (b) Identify ovipositian sites of Great Basin Gophersnakes (year 2) (c) Determine a population estimate for Nightsnakes (endangered) and Western skink (special concern skinks are a primary diet item of the Nightsnakes and these species co-occur on talus slopes) year 2.
  • Explanation for issuing permit(#SARA-PYR-2011-0167), persuant to the provisions of section 73 of SARA (2011-04-26)

    The objective of the project is to conduct scientific research on the Western Rattlesnake (Crotalus oreganus), Great Basin Gophersnake (Pituophis catenifer deserticola), Desert Nightsnake (Hypsiglena chlorophaea), and Western Skink (Plestiodon skiltonianus), in order to inform the conservation of the species. 34 adult male Western Rattlesnakes and 34 Great Basin Gophersnakes will be surgically implanted with radio-transmitters following an approved animal care protocol from the University of Guelph Animal Care Committee and the British Columbia Ministry of Water, Land and Air Protection, and re-located 3-4 times per week (between April 26, 2011 and October 31, 2013). Up to 100 individuals per year of each of these 4 species, Western Rattlesnakes, Great Basin Gophersnakes, Desert Nightsnake and Western Skink (male and female of all ages) will be part of a mark and recapture program. Individuals will have measurements taken following approved animal care protocol and immediately released back into the wild (between April 26, 2011 and October 31, 2013). This research will (a) identify densities and travel corridors of Western Rattlesnakes (threatened) years 1-2 and Great Basin Gophersnakes (threatened) years 1-2, (b) Identify ovipositian sites of Great Basin Gophersnakes (year 2), and (c) determine population estimates for Desert Nightsnake (endangered) and Western Skinks (special concern) year 2 (skinks are a primary diet item of the Desert Nightsnakes and these species co-occur on talus slopes).

Recovery Document Posting Plans

  • Environment and Climate Change Canada's Three-Year Recovery Document Posting Plan (2016-07-06)

    Environment and Climate Change Canada’s Three-Year Recovery Document Posting Plan identifies the species for which recovery documents will be posted each fiscal year starting in 2014-2015. Posting this three year plan on the Species at Risk Public Registry is intended to provide transparency to partners, stakeholders, and the public about Environment and Climate Change Canada’s plan to develop and post these proposed recovery strategies and management plans. However, both the number of documents and the particular species that are posted in a given year may change slightly due to a variety of circumstances. Last update December 2, 2021
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