Pituophis melanoleucus (Daudin, 1803) — Pine Snake

A species profile synthesized from Herpetological Review, volumes 1–54 (1967–2023). 171 index entries verified; 53 full-text articles on disk.

---

I. Taxonomy & Classification

Current Accepted Taxonomy

The genus Pituophis in North America was comprehensively revised by Rodriguez-Robles and de Jesus-Escobar (2000), as reviewed in Grismer (2001, HR 32(2):81), based on mitochondrial DNA analysis, morphological review, and distributional data. Their revision recognizes three species in the former P. melanoleucus complex:

• Pituophis melanoleucus — Eastern Pine Snakes (3 subspecies)
• Pituophis ruthveni — Louisiana Pine Snake
• Pituophis catenifer — Bull Snakes and Gopher Snakes (11 subspecies)

(Grismer 2001, HR 32(2):81; citing Rodriguez-Robles and de Jesus-Escobar 2000)

Grismer (2001) agreed with the treatment of the three Eastern taxa and the elevation of P. ruthveni, but disputed the synonymization of P. vertebralis (Cape Gopher Snake) and P. insulanus (Cedros Island Gopher Snake) into P. catenifer, arguing that both meet the same criteria — independence and diagnosability — used to elevate P. ruthveni (Grismer 2001, HR 32(2):81).

The disagreement pertains to the western catenifer complex and does not affect the taxonomy of the eastern species covered in this profile. ◇

Subspecies of P. melanoleucus

Subspecies	Common Name
P. m. melanoleucus	Northern Pine Snake
P. m. mugitus	Florida Pine Snake
P. m. lodingi	Black Pine Snake

Distributional ranges for each subspecies are detailed in Section II, built from HR geographic distribution records with specific locality data and voucher citations.

Molecular analysis demonstrates that melanoleucus, mugitus, and lodingi form a single, well-supported, diagnosable evolutionary lineage based on mtDNA characters (100% bootstrap value) and morphology (Reichling 1995, cited within Grismer 2001, HR 32(2):81; in turn citing Rodriguez-Robles and de Jesus-Escobar 2000).

Whether these three subspecies represent ecologically distinct entities — differing in diet, habitat use, behavior, or life history — or primarily reflect geographic and morphological variation within a cohesive lineage cannot be determined from the taxonomic literature alone. ◇ This question is addressed in subsequent sections as natural history data accumulate across subspecies.

Sister Species: Pituophis ruthveni

Pituophis ruthveni (Louisiana Pine Snake) was elevated to full species by Rodriguez-Robles and de Jesus-Escobar (2000) and maintained by Grismer (2001, HR 32(2):81). The basis for its elevation is allopatry — a broad alluvial plain deposited by the Mississippi River currently separates P. ruthveni from P. melanoleucus — combined with morphological diagnosability (Reichling 1995, cited within Grismer 2001, HR 32(2):81).

The mtDNA data show P. ruthveni as a non-exclusive (paraphyletic) lineage (Grismer 2001, HR 32(2):81; citing Rodriguez-Robles and de Jesus-Escobar 2000). Rodriguez-Robles and de Jesus-Escobar (2000) acknowledged this but argued that all lineages pass through a period of non-exclusivity reflecting the recency of their divergence, and that the diagnosability and allopatry of P. ruthveni demonstrate it is an independent, reproductively isolated evolutionary lineage (Grismer 2001, HR 32(2):81). The operative species concept supporting the elevation — and subsequently the species' listing under the Endangered Species Act (Rudolph et al. 2018, HR 49(4):609) — is allopatry plus morphological diagnosability, not reciprocal mtDNA monophyly.

Intergradation Zones

A specimen from Crenshaw County, Alabama was described as "collected midway between the range of P. m. melanoleucus to the north and P. m. mugitus to the south and may be intergradient" (Godwin 1984, HR 15(1):21; AUM 32239). A subsequent county record from Hale County, Alabama extended the range of P. m. melanoleucus to within one county of P. m. lodingi (Welker 2011, HR 42(2):244; UTA R 55651). These records suggest that central Alabama may be a zone of subspecific contact, though no genetic or morphological study of potential intergrades has been published in Herpetological Review. ◇

In Baja California, Grismer (1997, HR 28(2):68) re-examined a specimen from Valle de Trinidad (FMNH 1394) and concluded it is a probable intergrade between P. m. annectens and P. m. affinis (both now P. catenifer); Welsh and Bury (1984), cited therein, reported a similar intergrade ~9 km east of Paso de San Matias. This pertains to the P. catenifer complex and is noted here only for genus-level context. (Genus-level context — pertains to P. catenifer, not the focal P. melanoleucus.)

Taxonomic History

The nomenclatural history of this complex is marked by repeated lumping and splitting. ◆ Prior to 2000, all North American Pituophis were treated as subspecies of a single transcontinental species, P. melanoleucus (Grismer 2001, HR 32(2):81). The 2000 revision subdivided the complex, but disagreement persists on the exact number of species — particularly in the western part of the range, where Grismer (2001, HR 32(2):81) recognizes P. vertebralis and P. insulanus as full species while Rodriguez-Robles and de Jesus-Escobar (2000) include them in P. catenifer. Both authors employ the same species criteria (independence and diagnosability) but reach different conclusions when applied to non-exclusive lineages (Grismer 2001, HR 32(2):81).

At the species level, there is consensus across both authors: P. melanoleucus (with three subspecies), P. ruthveni, and P. catenifer are distinct species. ◆ The disagreement concerns species limits within the western P. catenifer complex (whether P. vertebralis and P. insulanus warrant elevation), and does not affect the eastern taxa covered in this profile.

---

II. Distribution

Geographic distribution records in Herpetological Review reflect the activity of GDR-submitting communities and road-cruising survey effort. ◇ The concentration of records in Georgia and the prevalence of DOR (dead on road) specimens should not be interpreted as reflecting population density or range limits. Many states within the known range of P. melanoleucus (including North Carolina, South Carolina, New Jersey, and Kentucky) are poorly represented in the HR GDR record despite confirmed species presence. ◆

P. m. melanoleucus (Northern Pine Snake)

Tennessee: New county records from Decatur County — DOR specimen at Lick Creek (35.43370°N, 88.04220°W; APSU 19071) (Colvin 2011, HR 42(1):115) — and Carroll County — DOR adult male (~153 cm TL) at Boyd's Landing Road (35.9354°N, 88.4612°W [latitude corrected per HR 46(1):64]; APSU 19493) (Maxwell and Scott 2014, HR 45(3):466).

Alabama (northern and central): New county record from Hale County — DOR adult female (474 g, 134.5 cm TL) extending the known range 12 km SW from the closest documented locality and bringing P. m. melanoleucus range "to within one county of P. m. lodingi" (32.954944°N, 87.482222°W; UTA R 55651) (Welker 2011, HR 42(2):244). Perry County: photo voucher (AUM AHAP-D 2624; 32.76421°N, 87.09442°W) collected 20 September 2021, a new county record lying approximately 14 km NW of the nearest vouchered locality in Chilton County and filling "a gap in the Fall Line Hills section of the Southeastern Plains ecoregion" (Bearden 2022, HR 53(4):586-587).

P. m. mugitus (Florida Pine Snake)

Florida: New county records from Osceola County in the Three Lakes Wildlife Management Area (27.8437°N, 81.1533°W; UF 166579) (Rushton and Rushton 2012, HR 43(3):449-450); Hamilton County at Suwannee Ridge Mitigation Park in sandhill habitat — adult male 1240 mm SVL captured by drift fence (30.44366°N, 83.04613°W; UF 173276) (Enge et al. 2015, HR 46(2):221).

P. m. lodingi (Black Pine Snake)

Mississippi: New county record from Lawrence County — DOR sub-adult male (100 cm SVL, 485 g) extending the northwest portion of the subspecies' range by 39.4 km (31.44268°N, 89.99398°W; MMNS 19455). This record increased the number of Mississippi counties documented for P. m. lodingi to 15 (Lee et al. 2017, HR 48(2):392).

P. melanoleucus — Subspecies Unattributed

Georgia dominates the HR GDR record for P. melanoleucus, with records from at least 10 counties. Many Georgia records do not assign subspecies, and the ranges of P. m. melanoleucus and P. m. mugitus may overlap in the state. ◇

County records include: Jenkins County (32.916356°N, 81.964642°W; ANSP 30934, 1976) and Pickens County (34.470814°N, 84.618497°W; GMNH 50098, 2007) (Jensen et al. 2011, HR 42(2):254); Irwin County (31.49841°N, 83.37635°W; UF 165275, 2011) (Mainor in Jensen et al. 2012, HR 43(3):456) and Pierce County in xeric sandhills on the east side of the Satilla River (31.297081°N, 82.360755°W; GSU 24857, 2012) (Stevenson and Wallace in Jensen et al. 2012, HR 43(3):456); Turner County (31.721190°N, 83.466210°W; GMNH 50415, 2013), Crawford County (32.682354°N, 84.079395°W; GMNH 50302, 2009), and Jeff Davis County (31.799900°N, 82.800598°W; GMNH 50390, 2013) (McKelvy 2014, HR 45(1):96; Stevenson 2014, HR 45(1):104); Lanier County, filling a gap between Berrien and Clinch counties (31.06017°N, 83.07092°W; GMNH 50983, 2014) (Stevenson 2021, HR 52(2):357).

Northwest Georgia outliers: Records from Floyd County (34.238928°N, 85.075805°W; GMNH 50920, 2010) and Bartow County (34.196396°N, 84.975512°W; GMNH 50760, 2014) document the species in northwest Georgia (Stevenson 2015, HR 46(4):596,600). These localities lie in the piedmont/mountain transition zone, notably outside the typical coastal plain and sandhill habitat associated with the species. ◇

Subspecies Contact Zones

The Crenshaw County specimen (1983) was described as potentially intergradient between P. m. melanoleucus and P. m. mugitus (Godwin 1984, HR 15(1):21). The Hale County record (2006) brings P. m. melanoleucus to within one county of P. m. lodingi (Welker 2011, HR 42(2):244). Together, these central Alabama records suggest a zone of subspecific contact (see Section I). ◇

P. ruthveni (Louisiana Pine Snake) — Historical Baseline

A GDR from Wood County, Texas documented P. ruthveni [as P. melanoleucas ruthveni in original] at a locality "330 km north of the northernmost Texas population records" (SFA-5038, 1973) (Rakowitz 1983, HR 14(3):88). This outlier record has not been confirmed by subsequent GDR submissions. ◇

Additional historical records include first-parish documentation from Calcasieu Parish (1988) and Jefferson Davis Parish (1966), Louisiana (Williams 1996, HR 27(1):35). These pre-1992 records contribute to the historical baseline against which Rudolph et al. (2018, HR 49(4):609) documented subsequent range contraction (see Section VII).

Unverified and Retracted Records

Historical literature reports of P. melanoleucus from Augusta, Bath, and Botetourt counties, Virginia (1939–1940) remain unverified by specimen (Mitchell 1987, HR 18(3):57).

---

III. Habitat & Fire Ecology

Habitat Association

Pituophis melanoleucus and its congeners are strongly associated with sandy, well-drained soils in open pine ecosystems. ◆ Rudolph et al. (1998) characterized P. ruthveni habitat as "sandy soils in longleaf pine (Pinus palustris) savannas" that were "historically maintained by frequent, low intensity ground fires." Preliminary telemetry results reported within the same study demonstrated that "Louisiana pine snakes are associated with sandy soils, savanna habitats with abundant herbaceous vegetation, and presence of Baird's pocket gophers (G. breviceps). Louisiana pine snakes spend substantial amounts of time underground, primarily in pocket gopher burrow systems, or coiled on the surface adjacent to entrances to pocket gopher burrow systems." (Rudolph et al. 1998, HR 29(3):146-155)

In the New Jersey Pine Barrens, P. m. melanoleucus females excavate nests "in open canopy, sandy upland areas" (Smith et al. 2013). Active management of New Jersey sites for Pine Snake populations has been mentioned in the HR corpus only as site context within an amphibian disease study (see Habitat Management below). (Monsen-Collar et al. 2013, HR 44(2):263)

Burrow Dependency

Fossorial refuge use is a defining ecological trait of the genus, ◇ but the primary burrow type differs across subspecies and geography:

• P. ruthveni (Louisiana Pine Snake): Primarily dependent on Baird's Pocket Gopher (Geomys breviceps) burrow systems for shelter, thermoregulation, hibernation, and fire escape. Estimated pocket gopher burrow temperatures of 11–16°C during winter/early spring (from transmitter data during prescribed burns). (Rudolph et al. 1998, HR 29(3):146-155)

• P. m. lodingi (Black Pine Snake): The only documented natural nest was associated with a Gopherus polyphemus (Gopher Tortoise) burrow at Camp Shelby, Mississippi (see Section V). (Lee et al. 2011, HR 42(2):301)

• P. m. mugitus (Florida Pine Snake): Documented as a burrow commensal of G. polyphemus — two individuals captured in funnel traps at tortoise burrows over 2551 trap-nights at the Katharine Ordway Preserve, Putnam County, Florida (Franz 1986). This low-frequency association (2 captures among 403 total amphibian and reptile captures across 19 species) documents presence at tortoise burrows but does not establish the intensity of the relationship. Franz noted that "with the continued decline in the number of gopher tortoises in the southeastern United States we might also see changes in populations of other sandhill amphibians, reptiles, and other wildlife which frequent their burrows." (Franz 1986, HR 17(3):64) Nesting records from Citrus County, Florida show P. m. mugitus using both tortoise burrow chambers and self-excavated chambers (see Section V). (Enge et al. 2019, HR 50(2):398-399)

• P. m. melanoleucus (Northern Pine Snake): Self-excavated nest burrows in open sandy uplands in the New Jersey Pine Barrens (Smith et al. 2013). Iverson et al. (2007) suggested that P. melanoleucus excavates its nest burrows while P. catenifer uses natural cavities or burrows. (Smith et al. 2013, HR 44(3):492-493; Lee et al. 2011, HR 42(2):301, citing Iverson et al. 2007)

Fire Ecology

The most detailed fire-response data come from Rudolph et al. (1998), who documented the behavior of nine radio-tracked P. ruthveni during prescribed burns in longleaf pine habitat in Texas and Louisiana, 1994–1997. All nine snakes survived exposure to prescribed fires with no apparent damage. Six were in the burned area but not under direct observation during fire passage; their aboveground/underground status at the time is unknown. (Rudolph et al. 1998, HR 29(3):146-155)

Three snakes were observed directly during fire passage, revealing two distinct behavioral strategies:

Strategy 1 — Near-burrow retreat (2 snakes): An adult female on 25 February 1994, coiled on the surface 1 m from her hibernation burrow entrance, initially moved 2 m downslope away from the approaching backfire, then reversed direction and moved toward the approaching fire and into the burrow when the fire was approximately 10 m distant. Transmitter temperature immediately dropped from 27.5°C toward estimated burrow temperature of 11–14°C. A second adult female on 10 March 1997 entered a burrow approximately 5 m distant when the fire was 2 m away. (Rudolph et al. 1998, HR 29(3):146-155)

Strategy 2 — Away from burrow, extended surface search (1 snake): An adult male on 10 March 1997, inadvertently disturbed by the observer, sheltered under grass cover until flames were within 20 cm, then emerged and moved rapidly parallel to the fire front — first 15 m in one direction, then reversing and moving 95 m in the opposite direction — before locating a subterranean retreat just before the fire passed over. No evidence of a burrow entrance was found afterward, though pocket gopher mounds were nearby. Rudolph et al. noted that "snakes on the surface and not near known burrows may be at greater risk." (Rudolph et al. 1998, HR 29(3):146-155)

Limitations: All observed fire events were "relatively slowly advancing backfires" with flame heights of 0.3–0.8 m, moving at 1–5 m per minute. Rudolph et al. noted that "the potential for mortality or injury to snakes due to rapidly advancing headfires is presumably greater, especially for snakes without immediate access to a burrow." Mortality of P. melanoleucus from prescribed fires has been reported in prairie habitats in Nebraska and Missouri (Erwin and Stasiak 1979; Seigel 1986, cited within Rudolph et al.), and eastern diamondback rattlesnake mortality has been documented during fires when snakes were in ecdysis (Means and Campbell 1981, cited within Rudolph et al.). Rudolph et al. noted: "Similar effects are possible with Louisiana pine snakes, but relevant observations are not available." (Rudolph et al. 1998, HR 29(3):146-155)

Fire-suppression hypothesis: Rudolph et al. hypothesized (citing Rudolph and Burgdorf 1997) that fire suppression leading to increases in woody midstory vegetation, consequent decline of herbaceous vegetation, and detrimental impacts on pocket gopher populations may have contributed to declines and local extirpations of Louisiana Pine Snakes. This hypothesis — fire suppression → woody vegetation → herbaceous decline → pocket gopher decline → Pine Snake decline — is presented as their explanatory framework, not as a demonstrated causal chain in this study. (Rudolph et al. 1998, HR 29(3):146-155; citing Rudolph and Burgdorf 1997)

Habitat Management

Active habitat management for P. melanoleucus has been documented in New Jersey: Monsen-Collar et al. (HR 44(2):263, a Ranavirus study) noted that study sites were managed "for the benefit of Pine Snake (Pituophis melanoleucus) populations" and that fields were "artificially cleared for pine snake management." These are the only published references to active habitat management for the species in the current HR corpus. (Monsen-Collar et al. 2013, HR 44(2):263; Pine Snake mentioned as site context within an amphibian disease study)

---

IV. Diet & Foraging

Pituophis melanoleucus is described as feeding "principally on small mammals, but has occasionally been recorded feeding on lizards, other snakes, and quail eggs" (Mortensen et al. 2019). The Herpetological Review record adds three notable observations of unexpected prey items and foraging behavior, each a single observation that extends the known dietary range of the genus without supporting population-level dietary characterizations.

Turtle Egg Consumption (P. melanoleucus)

At Fort Stewart, Long County, Georgia on 18 June 2018, an adult female P. melanoleucus (1156 mm SVL, 583.3 g at capture, 533.8 g post-digestion) was found near a Gopherus polyphemus burrow in Longleaf Pine sandhill habitat. Four discrete boluses were located 450–590 mm anterior to the cloaca. Ultrasound confirmed the items were spherical, suggesting turtle or bird eggs. Given the time of year, egg size and shape, and prevalence of G. polyphemus at the site, the most plausible food items were Gopher Tortoise eggs. Turtle eggs had not previously been reported in the diet of P. melanoleucus. The authors noted that given the sympatric occurrence of the two species in sandy uplands, tortoise eggs "may be an underappreciated food resource." (Mortensen et al. 2019, HR 50(4):811)

This observation adds a trophic dimension to the Gopherus polyphemus association documented elsewhere in this profile (see Section VI).

Burrowing Owl Predation (P. catenifer — genus-level context)

In the closely related P. catenifer (Gophersnake), a dead individual was found approximately 15 m from an active Burrowing Owl (Athene cunicularia) nest burrow at Kirtland Air Force Base, Bernalillo County, New Mexico on 25 May 2005. The cause of death of the snake was not determined. Dissection revealed the bolus was an adult Burrowing Owl that had been banded during an ongoing monitoring study. Painter et al. (2012) noted this as the first verified report of a Burrowing Owl being preyed upon by P. catenifer. Rodríguez-Robles (2002), cited within the article, found that 213 of more than 2,600 P. catenifer specimens examined (approximately 18%) contained birds or their eggs, but only two contained owl flesh or eggs — one with Short-eared Owl nestlings (Imler 1945) and one with Flammulated Owl eggs (McCallum et al. 1995) — indicating that owl content was uncommon even within this bird-consuming species. (Painter et al. 2012, HR 43(1):148)

Note: This observation pertains to P. catenifer, not P. melanoleucus, and is included as genus-level dietary context.

Known Gap: P. ruthveni Diet Study

Rudolph et al. (2012, HR 43(3):243) published the most comprehensive diet study for P. ruthveni (53 prey records from 46 wild-caught snakes). The full verbatim source text is not currently available in our corpus — the relevant pages are absent from the available PDF. Acquisition is in progress. When obtained, this section will be updated with the primary diet data for P. ruthveni, including prey composition, biomass estimates, and prey specialization analysis. [Gap flagged; extraction data exists but verbatim unverified]

Carrion Feeding (P. m. lodingi)

On 24 June 2005, a radio-tracked female P. m. lodingi (121 cm SVL, 615 g) at Camp Shelby Training Site, Perry County, Mississippi appeared to have recently fed. Upon palpation, the snake regurgitated a young fox squirrel (Sciurus niger) that was "fairly decomposed and completely covered in maggots (still alive)." The snake retreated to a nearby stump hole, and the squirrel was placed in front. The following day, the snake was in the same location and had presumably re-ingested the squirrel. Lee (2007) inferred from the maggot presence that the squirrel had died prior to being consumed, suggesting carrion-scavenging behavior. (Lee 2007, HR 38(1):92)

---

V. Reproduction & Nesting

Published wild reproductive data for Pituophis melanoleucus and P. ruthveni are sparse. For most subspecies, the published record in Herpetological Review consists of single observations or indirect inference from trapping data. What follows is the complete wild and captive record as documented in HR, presented at the individual-record level rather than as subspecies-level generalizations.

Nesting

P. m. lodingi (Black Pine Snake): On 3–4 September 2009, three hatchling P. m. lodingi were found basking at and near the apron of a Gopherus polyphemus (Gopher Tortoise) burrow at Camp Shelby Joint Forces Training Center, Perry County, Mississippi. Two hatchlings were on or adjacent to the burrow apron; a third was tightly coiled 6 m from the entrance. Burrow measurements: width 6.4 cm, height 3.5 cm, angle of declination 27°. Lee et al. (2011) interpreted this as the first documented natural nest for the subspecies, based on subsequent burrow excavation (excavation details in source article). (Lee et al. 2011, HR 42(2):301)

P. m. mugitus (Florida Pine Snake): The second and third known wild nest locations for this subspecies were described from Citrus County, Florida, both discovered during G. polyphemus burrow excavations for relocation in 2018.

Clutch 1 (19 July 2018): Eight eggs in a small cavity off the chamber at the end of a 4-m-long tortoise burrow occupied by a small adult male G. polyphemus (187 mm SCL). The egg chamber was approximately 2 m below the surface at the intersection of the final chamber and an adjoining rodent burrow. Habitat: 7-ha stand of densely planted 7-year-old Sand Pines, 50 m from improved pasture.

Clutch 2 (9 August 2018): Five eggs discovered 1.85 km from Clutch 1. The clutch was approximately 30 cm below surface in overgrown sandhill habitat with canopy of Sand Live Oak, Turkey Oak, and Post Oak. The egg chamber was apparently dug by the snake in sand beneath oak leaf litter and was not associated with the G. polyphemus burrow 3 m away. (Enge et al. 2019, HR 50(2):398-399)

These two clutches demonstrate within-subspecies variation in nest-site selection: P. m. mugitus both uses tortoise burrow chambers (Clutch 1) and excavates independent chambers unconnected to nearby burrows (Clutch 2).

P. m. melanoleucus (Northern Pine Snake): Smith et al. (2013) characterized New Jersey Pine Barrens P. melanoleucus females as excavating "nests in open canopy, sandy upland areas," with "test holes often dug by female Pituophis spp. near true nests, 30 cm deep." At the Franklin Parker Preserve, Chatsworth, New Jersey, fiber-optic camera investigations of active nests in July 2011 documented a Fowler's Toad (Anaxyrus fowleri) using an active Pine Snake nest; this nest produced four hatchling P. melanoleucus that year. (Smith et al. 2013, HR 44(3):492-493) Iverson et al. (2007), cited within Lee et al. (2011), suggested that "P. melanoleucus excavates its nest burrows, whereas P. catenifer uses natural cavities or burrows for oviposition," noting that further data were needed to test the pattern. (Lee et al. 2011, HR 42(2):301; citing Iverson et al. 2007)

Egg and Hatchling Data

The most quantitatively precise data come from the two P. m. mugitus clutches:

Clutch 1 (8 eggs, P. m. mugitus):

Parameter	Value
Total mass	602.5 g
Egg length	Mean 72.1 mm (SD 3.45, range 65.8–76.4 mm)
Egg width	Mean 43.4 mm (SD 1.02, range 41.8–44.8 mm)
Hatching date	20–22 September 2018
Hatchling SVL	Mean 429.9 mm (SD 6.99, range 420–440 mm)
Hatchling TL	Mean 489.1 mm (SD 6.11, range 476–500 mm)
Hatchling mass	Mean 59.8 g (SD 2.95, range 54.0–61.5 g)

(Enge et al. 2019, HR 50(2):398-399)

Clutch 2 (5 eggs, P. m. mugitus):

• Egg length: mean 87.8 mm (SD 4.91, range 82.8–94.1 mm)
• Egg width (4 eggs): mean 40.1 mm (SD 1.55, range 38.2–41.9 mm)
• One embryo killed during excavation

(Enge et al. 2019, HR 50(2):398-399)

Mating Behavior

Lee (2007) reported copulation in radio-tracked P. m. lodingi at Camp Shelby, Perry County, Mississippi on 28 September 2005. The male (149.5 cm SVL, 1001 g) was positioned entirely on top of the female (121.2 cm SVL, 615 g) with the exception of the tail, which was extended along the side of her body. Ambient air temperature was 33.2°C. The pair remained together in the same area for 3 days following the observation, located below ground in a rotted-out pine root system. (Lee 2007, HR 38(1):92-93)

Breeding Phenology (P. ruthveni)

Analysis of 132 trap captures of P. ruthveni across multiple sites in Texas and Louisiana over a 20+ year period (1994–2015) identified 10 male-female co-occurrences. Eight of these consisted of a female captured concurrently with or prior to males, and all eight occurred between 12 April and 6 June, suggesting an April–June breeding window. Pierce et al. explicitly noted: "To our knowledge, copulation has not been witnessed, nor has a nest been documented" for wild P. ruthveni. (Pierce et al. 2016, HR 47(2):315)

Clutch Data (P. ruthveni — wild-caught, captive oviposition)

A gravid female P. ruthveni captured crossing a sand road in Bienville Parish, Louisiana (~22 June 2003) deposited 6 eggs within 8–10 hours of being provided nest substrate (plastic box with damp sphagnum moss). One egg was infertile. The five viable eggs were incubated at 26–28°C for approximately 9 weeks in a 3:2 perlite/vermiculite mixture, producing 1 male and 4 females. Lodrigue (2008) noted: "There are almost no data available on reproduction in wild Pituophis ruthveni." (Lodrigue 2008, HR 39(3):357)

Captive Breeding — AZA Species Survival Program

At Zoo Atlanta, a female P. ruthveni produced a clutch of seven eggs on 27 May 2017. Four eggs survived to hatching. Upon pipping on 28 July 2017, one egg was found to contain two fully formed neonates — Twin 1 (32.2 g) and Twin 2 (32.4 g), each approximately half the mass of their siblings (67.9–71.5 g). Despite the size difference, both twins appeared outwardly normal and, as of July 2018, had surpassed their siblings in overall mass. Hill et al. (2019) noted that P. ruthveni has the smallest average clutch size and largest eggs of any snake species in the USA. The species is managed through a captive population of approximately 101 individuals (50 males, 51 females). (Hill et al. 2019, HR 50(1):88)

---

VI. Ecological Relationships

Fossorial Associations Across the Complex

A recurring pattern across the published HR record is the dependence of Pituophis on fossorial refuge systems. The specific association differs across subspecies and geography, but the dependency on underground refuge — for nesting, thermoregulation, hibernation, and fire escape — is consistent across all taxa with available data:

Taxon	Primary Fossorial Association	Evidence Source
P. ruthveni	Baird's Pocket Gopher (Geomys breviceps) burrows	HR 29(3):146, Rudolph et al.
P. m. lodingi	Gopher Tortoise (Gopherus polyphemus) burrows	HR 42(2):301, Lee et al.
P. m. mugitus	Gopher Tortoise burrows + self-excavated chambers	HR 17(3):64, Franz; HR 50(2):398, Enge et al.
P. m. melanoleucus	Self-excavated nest burrows	HR 44(3):492, Smith et al.

These associations carry conservation implications: the decline of Gopher Tortoises or pocket gophers may cascade to Pine Snake populations that depend on their burrow systems (see Section VII). Franz (1986) explicitly noted that "with the continued decline in the number of gopher tortoises in the southeastern United States we might also see changes in populations of other sandhill amphibians, reptiles, and other wildlife which frequent their burrows." (Franz 1986, HR 17(3):64)

Interspecific Nest Use

Smith et al. (2013) documented a Fowler's Toad (Anaxyrus fowleri) using an active P. melanoleucus nest in the New Jersey Pine Barrens via fiber-optic camera monitoring in July 2011. The nest produced four hatchling Pine Snakes that year. It remains unknown whether neonate P. melanoleucus prey on A. fowleri, "though the toads are prey to other snakes in the surrounding habitats." This single observation documents at least one case of interspecific use of a Pine Snake nest by another sandhill species; whether such use is common across nests is undocumented. (Smith et al. 2013, HR 44(3):492-493)

Predators and Antipredator Behavior

Three HR records document predation or predation attempts on Pituophis, each involving a different life stage and predator class.

Hawk predation on adult P. melanoleucus: On 22 June 2007, a P. melanoleucus (~1.2 m total length) was observed crossing a dirt road through mature Longleaf Pine forest at the Joseph W. Jones Ecological Research Center at Ichauway Plantation, Baker County, Georgia (31.210946°N, 84.445900°W). Approximately 90 minutes later, a raptor believed to be either a Buteo jamaicensis (Red-tailed Hawk) or B. lineatus (Red-shouldered Hawk) was observed carrying what appeared to be a dead P. melanoleucus of similar size approximately 50 m from the original sighting. Greene and Tracy (2011) noted that birds of prey were not previously listed among predators of P. melanoleucus, despite known heavy predation on P. catenifer by Red-tailed Hawks in the western United States. (Greene and Tracy 2011, HR 42(2):301-302)

Coachwhip predation attempt on subadult P. m. melanoleucus: On 27 May 2013, in Scotland County, North Carolina (34.98913°N, 79.52348°W), a telemetered adult male Eastern Coachwhip (Masticophis f. flagellum, ~180 cm total length) was observed attempting to consume a young male P. m. melanoleucus (~80 cm total length). The coachwhip seized the Pine Snake behind the head, shook it vigorously, and began to drag it away. The observer's presence may have influenced the outcome, as the coachwhip "released and re-seized the P. melanoleucus several times before finally abandoning it and retreating a considerable distance." The Pine Snake "offered little resistance during this ordeal, and some thanatosis may have been involved." The Pine Snake survived and was released five days later. (Murphy et al. 2014, HR 45(1):170)

Bullfrog predation on hatchling P. catenifer sayi (genus-level context): An adult American Bullfrog (Lithobates catesbeianus, ~16.5 cm SVL) captured at Hackberry Lake, Valentine National Wildlife Refuge, Cherry County, Nebraska in late August or early September 2015 contained a hatchling P. c. sayi (~40 cm total length). Pauley et al. (2018) noted that "previously, no species of frog has been documented to predate P. catenifer." This observation, while pertaining to a congener, demonstrates that hatchling Pituophis can fall prey to large anurans. (Pauley et al. 2018, HR 49(3):576-577; within a Lithobates catesbeianus diet entry)

Note: This observation pertains to P. catenifer sayi, not P. melanoleucus, and is included as genus-level life-stage vulnerability context.

---

VIII. Longevity, Growth & Health

Growth (P. ruthveni)

Pierce et al. (2014) reported growth rates for adult P. ruthveni without implanted radio transmitters, based on 8 recaptures (≥8 months between captures) from 2007 to 2013 across multiple sites in Texas (Angelina National Forest, Angelina and Jasper counties) and Louisiana (private property in Bienville Parish; Fort Polk, Vernon Parish). Monthly increases in SVL were highly variable, ranging from 0 to 0.49 cm/mo. Mean total-length growth rates were 0.28 cm/mo for males and 0.12 cm/mo for females, with a tendency for smaller animals to grow faster.

These rates were generally similar to those reported for radio-tracked individuals by Himes et al. (2002), cited within Pierce et al. (males 0.26 cm/mo, females 0.30 cm/mo). Pierce et al. concluded that "transmitters may not be a major detriment to growth," but noted that "other studies have shown negative effects on mass gain and survival." The species was described as "a candidate species under the U.S. Endangered Species Act" at the time of the study; it was subsequently listed as Threatened in 2018 (see Section VII). (Rudolph et al. 2018, HR 49(4):609-619) Pierce et al. noted that P. ruthveni is "now restricted to seven (several possibly recently extirpated) isolated populations." (Pierce et al. 2014, HR 45(3):519-520)

Maximum Longevity Record

Dodd (2019) stated: "No information is available on the longevity of wild-caught individuals" of P. m. mugitus. The maximum captive longevity prior to this report was a wild-caught male held 18 years, 11 months, 21 days by Zoo Atlanta.

On 4 May 1987, Dodd captured a subadult male P. m. mugitus crossing County Road 29 (27.25870°N, 81.30521°W; 25.9 m elevation) northeast of Archbold Biological Station in Highlands County, Florida. The snake was retained because "the area to the west was being actively bulldozed for residential development; at the time, the species was not protected under state law." The snake lived in captivity until 30 May 2019, when it died of cancer. At the time of death, SVL was 106 cm with a tail length of 15 cm.

The minimum age at death was 32 years. Given that the snake was not considered adult at capture and sexual maturity in P. m. mugitus is reached at approximately 3 years, Dodd considered it "probable that this individual was 1–2 y older than 32 at death." Other subspecies of P. melanoleucus have reached 20–22 years in captivity. The specimen was deposited in the herpetology collection at the Florida Museum of Natural History (UF 188718). (Dodd 2019, HR 50(3):519)

Pathology

The longevity-record individual died from intestinal carcinomas: "Numerous large tumors formed external to the large intestinal tract anterior to the vent, thus inhibiting evacuation of fecal matter. An attempt to remove the tumors was unsuccessful." Dodd noted that "reports of non-epidermal carcinomas are rare in snakes," and the observation may be of interest to veterinary pathologists. The snake and its tumors were deposited together (UF 188718). (Dodd 2019, HR 50(3):519)

Transmitter-Related Mortality

Lutterschmidt et al. (2012), reporting an observation attributed to HKR, described a Pituophis melanoleucus that died after a radio transmitter without a paraffin-beeswax coating migrated anteriorly and lodged in the snake's lung, causing "extensive irritation, inflammation, and eventual death." The snake had been "sedentary and lethargic for several months prior to its death." This case study, drawn from a methodology article on transmitter surgery techniques, documents a fatal outcome from uncoated transmitter migration. (Lutterschmidt et al. 2012, HR 43(3):383)

---

IX. Notable Observations

This section will compile unusual or historically significant records that do not fit cleanly into the topical sections above. Content from Brief 4:

• Thanatosis behavior: A young P. m. melanoleucus exhibited possible death-feigning during a coachwhip predation attempt — "some thanatosis may have been involved" (see Section VI). If confirmed in future observations, this would represent an additional antipredator strategy for the species. (Murphy et al. 2014, HR 45(1):170)

---

VII. Conservation

Listing Status

Pituophis ruthveni was designated a Candidate Species under the U.S. Endangered Species Act in 1999, and ultimately listed as a Threatened Species in 2018. The species is listed as Endangered on the IUCN Red List (Hammerson 2007). (Rudolph et al. 2018, HR 49(4):609-619)

The species-level recognition supporting the ESA listing rests on the taxonomic framework established by Rodriguez-Robles and de Jesus-Escobar (2000), in which P. ruthveni was elevated to full species based on allopatry and morphological diagnosability (see Section I). (Grismer 2001, HR 32(2):81; citing Rodriguez-Robles and de Jesus-Escobar 2000)

As of 1975, no Catalog of American Amphibians and Reptiles account had been published for P. melanoleucus. (Zweifel 1975, HR 6(2):46)

Population Status and Decline

Rudolph et al. (2018) presented the most comprehensive assessment of P. ruthveni population status, analyzing trap-capture data and incidental records spanning 1929–2015 across five populations:

Range contraction: Prior to 1992, P. ruthveni had been recorded from 11 counties in Texas and 7 parishes in Louisiana (N=84 records since the species description in 1929). From 1992 to 2015, records came from only 6 counties in Texas and 5 parishes in Louisiana (N=151 records), with an absence of post-1991 records from five Texas counties and two Louisiana parishes. (Rudolph et al. 2018, HR 49(4):609-619)

Incidental record decline: Incidental (non-trap) records declined 60% between the first and second halves of the 1992–2015 monitoring period: 35 records in 1992–2003 versus 14 in 2004–2015. Rudolph et al. noted that "although effort expended in locating snakes is unknown, we believe the amount of effort increased substantially in the last half of this period due to many more observers involved in conservation activities" — the decline occurred despite increased, not decreased, search effort. (Rudolph et al. 2018, HR 49(4):609-619)

Population-specific trends (state-space CSEG model):

Population	Estimated Annual Decline	Certainty	Projected 90% Decline
ANF (Angelina NF)	~17%/yr	High (very low variability)	Within 15 years
N/S (Newton/Sabine)	~9%/yr	High (low variability)	Within 30 years
BP (Bienville Parish)	~4%/yr	High	~74 years
FP (Fort Polk)	~3-4%/yr	Low (95% CIs included zero)	Uncertain
PR (Peason Ridge)	Insufficient data	—	—

Rudolph et al. cautioned that "models estimating quasi-extinction risk assume future environmental conditions will be similar to the present. Caution is advised in relying on estimates too far into the future." (Rudolph et al. 2018, HR 49(4):609-619)

All five populations met IUCN Criterion B for Critically Endangered in 2010–2015 (occupied habitat < 10,000 ha). The Angelina NF population met Criterion E for Critically Endangered using a 99% decline threshold within 33 years; the N/S population also met Criterion E using a 90% decline threshold. (Rudolph et al. 2018, HR 49(4):609-619)

Texas status: Rudolph et al. reported "no detections of P. ruthveni in either of the state's populations since 2008" (with two exceptions) and concluded that they were "not optimistic that viable populations still occur in Texas" and expressed concern that "extirpation in the state is imminent, if it has not already occurred." (Rudolph et al. 2018, HR 49(4):609-619)

Note: Pierce et al. (2014) referenced "seven (several possibly recently extirpated) isolated populations," reflecting an earlier USFWS population designation. Rudolph et al. (2018) consolidated to five populations for their analysis.

Threats

The threats to P. ruthveni as documented across the HR corpus include:

1. Fire suppression and vegetation succession. Rudolph et al. hypothesized (citing Rudolph and Burgdorf 1997) that fire suppression leading to woody midstory increase, herbaceous vegetation decline, and consequent pocket gopher population decline may have contributed to Pine Snake declines (see Section III). (Rudolph et al. 1998, HR 29(3):146-155)

2. Intensive silviculture. Intensive short-rotation pine silviculture, herbicide use, and litter buildup in the absence of fire alter the longleaf pine savanna ecosystem on which P. ruthveni depends. (Rudolph et al. 2018, HR 49(4):609-619)

3. Habitat loss and fragmentation. Direct documentation: Dodd (2019) retained a P. m. mugitus specimen because the capture site "was being actively bulldozed for residential development" (see Section VIII). (Dodd 2019, HR 50(3):519)

4. Low fecundity. Hill et al. (2019) noted that P. ruthveni has the smallest average clutch size of any snake species in the USA, compounding the impact of adult mortality on population recovery. (Hill et al. 2019, HR 50(1):88)

5. Road mortality. Rudolph et al. (2018) cite their 1999 study (not in current HR corpus) on road mortality as an established threat to P. ruthveni populations. Multiple GDR records in the current corpus document DOR (dead on road) specimens across the range (see Section II). (Rudolph et al. 2018, HR 49(4):609-619)

Recovery and Repatriation

Captive breeding program: A captive population of P. ruthveni was established at the Memphis Zoo and has expanded over time into a multi-institution AZA Species Survival Program. As of 2019, the SSP managed approximately 101 individuals (50 males, 51 females), with participating institutions including Zoo Atlanta. (Rudolph et al. 2018, HR 49(4):609-619; Hill et al. 2019, HR 50(1):88)

Repatriation: On 19 July 2010, three captive-bred P. ruthveni were released onto restored habitat within the Kisatchie National Forest in Louisiana — a site within the species' historic range where no snakes had been reported after 3,749 trap-days during 2004–2009. This marked a major milestone in a cooperative effort between the U.S. Forest Service, U.S. Fish and Wildlife Service, Louisiana Department of Wildlife and Fisheries, and the AZA SSP. By 2020, a total of 178 captive-bred individuals had been repatriated to this site, all PIT-tagged. Monitoring indicated that "a significant portion of the released snakes have survived, grown, and acclimated to the natural environment." (Hinkson et al. 2020, HR 51(3):625-626)

As of the 2018 assessment, Rudolph et al. reported that 94 individuals had been released and initial indications of growth and survival were encouraging, but "reproduction has yet to be documented." (Rudolph et al. 2018, HR 49(4):609-619)

First repatriated reproduction: On 21 June 2016, an untagged individual (Snake X, SVL 116.3 cm) was captured at the Catahoula Ranger District release site in Grant Parish, Louisiana. Genetic analysis using 14 microsatellite loci across shed samples from all 75 individuals released before Snake X's discovery confirmed a female hatched in 2010 and released in 2011 as the most likely mother, "with 99% statistical confidence." No father was confidently assigned. Identity analysis ruled out the possibility of a released snake that had lost its PIT tag. Hinkson et al. (2020) described this as "a highpoint in the repatriation efforts of this species" indicating that "captive-bred, released Louisiana Pinesnakes are able to survive and reproduce in the wild." (Hinkson et al. 2020, HR 51(3):625-626)

Management Priorities

Rudolph et al. (2018) identified three priorities for the species' recovery:

1. "Identification and management of additional reintroduction sites"
2. "Obtaining additional genetic material to bolster that presently available in the captive population"
3. "Commitment of adequate resources to increase the size of the captive population and increase the production of genetically appropriate snakes for reintroduction"

(Rudolph et al. 2018, HR 49(4):609-619)

---

---

Epistemic Notation Legend

◆ Established knowledge — the author is confident this is established subspecialty fact ◇ Expert assessment — widely accepted; some reviewers may seek additional sourcing ○ Expert inference — derived from known principles, not directly from cited literature All other claims are either cited from the extraction records or are foundational knowledge.

---

Section X (Sources & Citations) to be compiled from all sections upon profile completion.