FWS Focus

Overview

The northern Mexican gartersnake may occur with other native gartersnake species and can be difficult for people without herpetological expertise to identify. With a maximum known length of 44 inches (in) (112 centimeters (cm)), it ranges in background color from olive to olive-brown to olive-gray with three stripes that run the length of the body. The middle dorsal stripe is yellow and darkens toward the tail. The pale yellow to light-tan lateral stripes distinguish the Mexican gartersnake from other sympatric (co-occurring) gartersnake species because a portion of the lateral stripe is found on the fourth scale row, while it is confined to lower scale rows for other species.
Throughout its rangewide distribution, the northern Mexican gartersnake occurs at elevations from 130 to 8,497 feet (ft) (40 to 2,590 meters (m)) (Rossman et al. 1996, p. 172). The northern Mexican gartersnake is considered a riparian riparian
Definition of riparian habitat or riparian areas.

Learn more about riparian
obligate (restricted to riparian areas when not engaged in dispersal behavior) and occurs
chiefly in the following general habitat types: (1) Source-area wetlands [e.g., cienegas (mid-elevation wetlands with highly organic, reducing (basic, or alkaline) soils), stock tanks (small earthen impoundment), etc.]; (2) large river riparian woodlands and forests; and (3) streamside gallery forests (as defined by well-developed broadleaf deciduous riparian forests with limited, if any, herbaceous
ground cover or dense grass).

Scientific Name

Thamnophis eques megalops
Common Name
Northern Mexican Garter Snake
Northern Mexican Gartersnake
Brown Gartersnake
FWS Category
Reptiles
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Geography

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Timeline

Explore the information available for this taxon's timeline. You can select an event on the timeline to view more information, or cycle through the content available in the carousel below.

24 Items

Listing

Listing

Listing

Listing

Listing

Listing

Notice

Listing

Listing

Listing

Listing

Listing

Listing

Listing

Listing

Listing

Listing

Critical Habitat

Listing

4d

Listing

Five Year Review

Critical Habitat

Critical Habitat

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Listing

Sep 18, 1985

Sep 18, 1985 Listing
Review of Vertebrate Wildlife; Notice of Review; 50 FR 37958-37967
  • Publication type: CNOR
Item 1

Listing

Jan 6, 1989

Jan 6, 1989 Listing
ETWP; Animal Notice of Review; 54 FR 554 579
  • Publication type: CNOR
Item 2

Listing

Nov 21, 1991

Nov 21, 1991 Listing
ETWP; Animal Candidate Review for Listing as Endangered or Threatened Species; 56 FR 58804 58836
  • Publication type: CNOR
Item 3

Listing

Nov 15, 1994

Nov 15, 1994 Listing
ETWP; Animal Candidate Review for Listing as Endangered or Threatened Species.
  • Publication type: CNOR
Item 4

Listing

Jan 4, 2006

Jan 4, 2006 Listing (Substantial)
90-Day Finding on a Petition To List the Northern Mexican Gartersnake as threatened or Endangered Wiโ€ฆ
  • Publication type: 90 day petition finding
Item 5

Listing

Sep 26, 2006

Sep 26, 2006 Listing (Not Warranted)
12-Month Finding on a Petition To List the Northern Mexican Gartersnake (Thamnophis eques megalops)โ€ฆ
  • Publication type: 12m petition finding
Item 6

Notice

May 28, 2008

May 28, 2008 Notice (Information Solicitation)
Initiation of Status Review for the Northern Mexican Gartersnake (Thamnophis eques megalops)
  • Publication type: Status Review Initiation
Item 7

Listing

Nov 25, 2008

Nov 25, 2008 Listing (Warranted But Precluded)
12-Month Finding on a Petition To List the Northern Mexican Gartersnake (Thamnophis eques megalops)โ€ฆ
  • Publication type: 12m petition finding
Item 8

Listing

Dec 10, 2008

Dec 10, 2008 Listing
Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Noticโ€ฆ
  • Publication type: CNOR
Item 9

Listing

Nov 9, 2009

Nov 9, 2009 Listing (Warranted But Precluded: Resubmitted)
Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Noticeโ€ฆ
  • Publication type: 12m petition finding
Item 10

Listing

Nov 9, 2009

Nov 9, 2009 Listing
Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Noticeโ€ฆ
  • Publication type: CNOR
Item 11

Listing

Nov 10, 2010

Nov 10, 2010 Listing
Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Noticeโ€ฆ
  • Publication type: CNOR
Item 12

Listing

Nov 10, 2010

Nov 10, 2010 Listing (Warranted But Precluded: Resubmitted)
Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Noticeโ€ฆ
  • Publication type: 12m petition finding
Item 13

Listing

Oct 26, 2011

Oct 26, 2011 Listing
Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Noticeโ€ฆ
  • Publication type: CNOR
Item 14

Listing

Oct 26, 2011

Oct 26, 2011 Listing (Warranted But Precluded: Resubmitted)
Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Noticeโ€ฆ
  • Publication type: 12m petition finding
Item 15

Listing

Nov 21, 2012

Nov 21, 2012 Listing (Warranted But Precluded: Resubmitted)
Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Noticeโ€ฆ
  • Publication type: 12m petition finding
Item 16

Listing

Nov 21, 2012

Nov 21, 2012 Listing
Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Noticeโ€ฆ
  • Publication type: CNOR
Item 17

Critical Habitat

Jul 10, 2013

Jul 10, 2013 Critical Habitat
Designation of Critical Habitat for the Northern Mexican Gartersnake and Narrow-Headed Gartersnake:โ€ฆ
  • Publication type: Proposed
Item 18

Listing

Jul 10, 2013

Jul 10, 2013 Listing (Threatened)
Threatened Status for the Northern Mexican Gartersnake and Narrow-headed Gartersnake: Proposed Rule.
  • Publication type: Proposed
Item 19

4d

Jul 8, 2014

Jul 8, 2014 4d
Threatened Status for the Northern Mexican Gartersnake and Narrow-Headed Gartersnake; Final Rule
  • Publication type: Final
Item 20

Listing

Jul 8, 2014

Jul 8, 2014 Listing (Threatened)
Threatened Status for the Northern Mexican Gartersnake and Narrow-Headed Gartersnake; Final Rule
  • Publication type: Final
Item 21

Five Year Review

Jul 26, 2019

Jul 26, 2019 Five Year Review (Information Solicitation)
5-Year Status Reviews of 36 Species in Arizona, New Mexico, Texas, Utah, and Mexico; Notice of initiโ€ฆ
  • Publication type: Notice
Item 22

Critical Habitat

Apr 28, 2020

Apr 28, 2020 Critical Habitat (Revision)
Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Northern Mexiโ€ฆ
  • Publication type: Proposed
Item 23

Critical Habitat

Apr 28, 2021

Apr 28, 2021 Critical Habitat
Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Northern Mexiโ€ฆ
  • Publication type: Final
Item 24