Louisiana pine snake (Pituophis ruthveni)
|Also known as:||Louisiana pinesnake|
|Synonyms:||Pituophis catenifer ruthveni, Pituophis melanoleucus ruthveni|
|Size||Total length: up to 179 cm (2)|
- The Louisiana pine snake is one of the rarest snakes in North America.
- Its limited range, reclusive habits and low numbers mean the Louisiana pine snake is also one of the least well understood large snakes in the United States.
- The Louisiana pine snake is non-venomous, instead using its body to crush its prey.
- The Louisiana pine snake depends on pocket gophers for food, and relies on their burrows for shelter and for hibernation sites.
- The eggs and hatchlings of the Louisiana pine snake are the largest of any snake in the United States, but its clutch size is one of the smallest.
The Louisiana pine snake is classified as Endangered (EN) on the IUCN Red List (1).
The Louisiana pine snake (Pituophis ruthveni) has long been considered one of the rarest snakes in the United States (3) (4). A large, relatively heavy-bodied snake (2), the Louisiana pine snake can be identified by its distinctive colouration and patterning, which consists of dark blotches on a yellow-brown background colour. Typically, the dark blotches blend together in the head and neck region, but increase in contrast and distinctiveness towards the middle of the body and the tail (2) (5). The blotches on the neck often contain spots, streaks or even patches of the yellowish background colour (5).
The blotches on the front part of the Louisiana pine snake’s body are usually dark brown to black, but become a lighter, richer reddish-brown towards the tail (2) (5) (6). The head is generally marked with many small, dark brown to reddish-brown spots, and in some individuals there is a narrow dark line between the eyes (2) (5). The Louisiana pine snake has a yellowish-buff underside with small, irregular dark markings (2) (5) (6).
There are not reported to be any major differences in appearance between the male and female Louisiana pine snake, apart from the female generally being shorter in length (7). Although the Louisiana pine snake may potentially grow to up to 179 centimetres long, lengths of up to about 152 centimetres are more common (2).
The Louisiana pine snake was previously treated as a subspecies of the pine snake (Pituophis melanoleucus) (1), but studies have shown it to be a separate species (8).
As suggested by its common name, the Louisiana pine snake can be found in parts of west-central Louisiana in the United States. It also occurs in eastern Texas, but its overall range has declined in recent decades (1) (3).
This snake is primarily found in open longleaf pine (Pinus palustris) savanna, in areas with sandy, well-drained soil and abundant herbaceous ground cover (1) (4). The Louisiana pine snake is typically found in longleaf pine-oak sandhills interspersed with moist bottomlands (low-lying land near rivers), but it is also known to reside in sandy shortleaf pine (Pinus echinata) and post oak (Quercus stellata) forest, as well as in blackjack oak (Quercus marilandica) woodland (1) (2).
The Louisiana pine snake tends to prefer open and disturbed woodland over dense forest, and can often be found in fields, farmland and areas of secondary growth (1) (2).
Due to its limited range, reclusive nature and low numbers, the Louisiana pine snake is perhaps one of the least well understood large snakes in the United States (10). However, a handful of studies exist which have given some insight into its mysterious life. The Louisiana pine snake is non-venomous (4), relying instead on its powerful muscles to crush its prey. Its primary source of food is Baird’s pocket gopher (Geomys breviceps) (1) (4) (9), and it is often found in or immediately adjacent to pocket gopher burrow systems (10). However, the Louisiana pine snake is also likely to feed on other small mammals, as well as birds, bird and turtle eggs, and sometimes lizards (2) (4) (9).
The Louisiana pine snake is likely to hunt pocket gophers within their underground burrows, moving rapidly through the burrow and then using its body to pin the gopher to the side and crush it. If the gopher backfills the burrow to prevent the snake’s advance, the Louisiana pine snake is usually able to use its head and neck to dig through the barrier (9).
Over half of the Louisiana pine snake’s time is spent below ground, usually within a pocket gopher burrow (4). This snake has been reported to be most active in the late morning and mid-afternoon, and only makes short-range movements above ground (4), typically from one gopher burrow to another (1) (4). The Louisiana pine snake also hibernates inside a pocket gopher burrow during the winter months (4) (10) (11), but unlike the pine snake (P. melanoleucus)it does not appear to excavate its own burrows, instead just slightly enlarging pre-existing chambers (11).
Similarly to its close relative the gopher snake (Pituophis catenifer), the Louisiana pine snake may exhibit an aggressive display when approached or provoked, hissing loudly, spreading its head and sometimes vibrating its tail (2).
Most information on reproduction in the Louisiana pine snake is from captive breeding studies. In captivity, this species mates around March and lays its eggs from April to May (2), usually around 21 days after mating (4). The Louisiana pine snake has an exceptionally small clutch size of three to five eggs, which is the smallest clutch of any North American snake (4). However, its eggs are remarkably large, measuring up to 11.8 centimetres in length and 3.4 centimetres in diameter, making them the largest of any snake in the United States (2) (4).
The eggs of the Louisiana pine snake are likely to be laid in an underground chamber and hatch after 58 to 66 days. The hatchlings measure an impressive 44 to 56 centimetres in length (2), with their large size potentially being an adaptation that allows them to quickly grow large enough to prey on pocket gophers (9). The young Louisiana pine snakes are likely to become sexually mature at around 3 years old, when they reach a total length of at least 120 centimetres (4).
The Louisiana pine snake’s natural habitat is one of the most threatened ecosystems in the United States (12). Most of the longleaf pine ecosystem has been logged or has been destroyed or degraded by other land uses, such as urbanisation, agriculture and intensive cultivation of other pine species (1) (2) (3) (4) (10). Only around three percent of its original extent now remains (13).
Also affected by this loss of habitat is Baird’s pocket gopher. The presence of pocket gophers is an essential requirement of the Louisiana pine snake’s habitat, as the snake relies on the gophers for food and depends on their burrows for shelter and hibernation sites. Declining pocket gopher numbers therefore present a serious threat to the Louisiana pine snake (1) (3) (4) (10).
Further loss of longleaf pine habitat can be attributed to changes in fire regimes. Longleaf pine ecosystems are dependent on frequent but low-intensity ground fires, but human alterations to fire regimes have led to wildlife suppression. The lack of frequent ground fires enables the progressive build-up of woody vegetation, forming a dense midstorey that suppresses the growth of the previously well-developed herbaceous understorey. These changes make the habitat unsuitable for pocket gophers and therefore also for the Louisiana pine snake (3) (4) (9).
There is also evidence to suggest that increasing road density and subsequent vehicular traffic is a threat to the Louisiana pine snake (1) (2) (4). A number of vehicle-related mortalities were reported in a study of radio-tracked snakes (7), and research suggests that populations of large snake species may be reduced by 50 percent or more within 450 metres of roads with moderate traffic levels (14). Most of the Louisiana pine snake’s habitat occurs within 500 metres of roads (1).
Other potential threats to the Louisiana pine snake include collection for the pet trade and direct killing by humans (1) (2) (4). The low reproductive rate of this species makes it particularly vulnerable to population declines (4) (10).
Surveys suggest that the Louisiana pine snake has declined in range and abundance as a result of these threats, and it now only occurs in small populations in highly fragmented patches of habitat (1) (3) (4). It is now one of the rarest snakes in North America (4).
A Candidate Conservation Agreement was established in 2004 to protect, conserve and manage the Louisiana pine snake. This agreement involves protecting remaining populations and their habitat, restoring degraded habitat, maintaining the longleaf pine ecosystem and reducing the threats to the Louisiana pine snake’s survival (1) (4).
The Louisiana pine snake is a ‘Candidate Species’ for federal listing under the U.S. Endangered Species Act, meaning it is under review for possible listing as threatened or endangered, but is not yet legally protected (6). This species is listed as ‘threatened’ in Texas, where it is protected from direct harm and unauthorised collection (4).
The long-term survival of the Louisiana pine snake will depend on management measures that reverse the decline in its fire-dependent habitat (3). In addition, further research is needed into the Louisiana pine snake’s populations, range, behaviour and management requirements. The Louisiana Department of Wildlife and Fisheries is currently working with the U.S. Fish and Wildlife Service, the U.S. Forest Service and a number of zoos on a re-introduction project for this highly threatened snake (15).
Find out more about the Louisiana pine snake and its conservation:
The Reptile Database:
U.S. Fish and Wildlife Service, Southwest Region - Louisiana pine snake (Pituophis ruthveni):
More information on reptile conservation:
International Reptile Conservation Foundation:
Partners in Amphibian and Reptile Conservation (PARC):
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
- Herbaceous: describes a small, non-woody, seed bearing plant in which all the aerial parts die back at the end of each growing season.
- Hibernation: a winter survival strategy in which the animal passes the winter in a resting state. This period of inactivity is characterised by specific biological and biochemical changes including lowered blood pressure and respiration rate. In reptiles, this is also known as brumation.
- Secondary growth: vegetation that has re-grown after a major disturbance, such as fire or clearance.
- Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
IUCN Red List (January, 2011)
- Werler, J.E. and Dixon, J.R. (2000) Texas Snakes: Identification, Distribution, and Natural History. University of Texas Press, Austin, Texas.
- Rudolph, D.C., Burgdorf, S.J., Schaefer, R.R., Conner, R.N. and Maxey, R.W. (2006) Status of Pituophis ruthveni (Louisiana pine snake). Southeastern Naturalist, 5(3): 463-472.
U.S. Fish and Wildlife Service, Southwest Region - Louisiana pine snake (Pituophis ruthveni) (August, 2012)
- Conant, R. (1956) A review of two rare pine snakes from the Gulf Coastal Plain. American Museum Novitates, 1781: 1-31.
U.S. Fish and Wildlife Service: Species Profile - Louisiana pine snake (Pituophis ruthveni) (August, 2012)
- Himes, J.G., Hardy, L.M., Rudolph, D.C. and Burgdorf, S.J. (2002) Growth rates and mortality of the Louisiana pine snake (Pituophis ruthveni). Journal of Herpetology, 36(4): 683-687.
- Reichling, S.B. (1995) The taxonomic status of the Louisiana pine snake (Pituophis melanoleucus ruthveni) and its relevance to the evolutionary species concept. Journal of Herpetology, 29(2): 186-198.
- Rudolph, D.C., Burgdorf, S.J., Conner, R.N., Collins, C.S., Saenz, D., Schaefer, R.R. and Trees, T. (2002) Prey handling and diet of the Louisiana pine snakes (Pituophis ruthveni) and black pine snakes (P. melanoleucus lodingi), with comparisons to other selected colubrid snakes. Herpetological Natural History, 9(1): 57-62.
- Rudolph, D.C. and Burgdorf, S.J. (1997) Timber rattlesnakes and Louisiana pine snakes of the West Gulf Coastal Plain: hypotheses of decline. Texas Journal of Science, 49(3): 111-122.
- Rudolph, D.C., Schaefer, R.R., Burgdorf, S.J., Duran, M. and Conner, R.N. (2007) Pine snake (Pituophis ruthveni and Pituophis melanoleucus lodingi) hibernacula. Journal of Herpetology, 41(4): 560-565.
- Bridges, E.L. and Orzell, S.L. (1989) Longleaf pine communities of the West Gulf Coastal Plain. Natural Areas Journal, 9: 246-263.
- Frost, C.C. (1993) Four centuries of changing landscape patterns in the longleaf pine ecosystem. In: Hermann, S.M. (Ed.) Proceedings of the Tall Timbers Fire Ecology Conference, No. 18. The Longleaf Pine Ecosystem: Ecology, Restoration and Management. Tall Timbers Research Station, Tallahassee, Florida.
- Rudolph, D.C., Burgdorf, S.J., Conner, R.N. and Schaefer, R.R. (1999) Preliminary evaluation of the impact of roads and associated vehicular traffic on snake populations in eastern Texas. In: Evink, G.L., Garrett, P. and Zeigler, D. (Eds.) Proceedings of the Third International Conference on Wildlife Ecology and Transportation, FL-ER-73-99. Florida Department of Transportation, Tallahassee, Florida.
Louisiana Department of Wildlife and Fisheries: Rare Animals of Louisiana - Louisiana Pine Snake (August, 2012)