Gopher snake - Pituophis catenifer

[Ceratodromeus]

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Colubridae
Subfamily: Colubrinae
Genus: Pituophis
Species: P.catenifer

Subspecies
 - P.c.affinis - Sonoran gopher snake
 - P.c. annectens - San diego gopher snake
 - P.c. catenifer - Pacific gopher snake
 - P.c. deserticola - Great basin gopher snake
 - P.c. pumilis - Santa cruz gopher snake
 - P.c. sayi - Bullsnake

Description
This is a mid sized species, with most adult animals falling in the 0.8-1.5m(2.6-4.9ft) in snout-vent length{1,2}, with the largest animals measuring an astonishing 2.7m(8.8ft) in snout-vent length{1}, making the species one of the largest native to north america. One study published in 2008 on Nebraskan bull snakes found an average adult total body length of 1.08m(3.5ft){3}. Appearance wise, the species is rather diverse. For example, the san diego subspecies is a darker reddish brown coloration, but retains it's chain like dorsal patterning that gives the species it's species name. Other subbspecies are a lighter coloration, like the Great basin gopher snake.

Geographic distribution & habitat use
This is a, geographically speaking, very successful species. Ranging from California to Missouri, and even down into Northern Mexico. They are accomplished burrowing animals, using their head to craft burrows that one would not expect from an animal with no arms or legs{4}. They are also accomplished swimmers and climbers, but are particularly fond of grassland habitats, where they are most commonly found{2}. They are primarily diurnal, but on occasion can be found being active at dusk & dawn{1}.

Dietary habits
Gopher Snakes do not stry far from their home ranges while foraging. Like other snakes, they hunt via visual and scent cues, and when they're close enough to their targeted prey item, they will strike with surprising speed, wrapping the unsuspecting animal in their powerful coils. These snakes predominately eat mammals, which includes pocket gophers (Geomys ,Thomomys), Voles(Microtus), white footed mice(Peromyscus), ground squirrels(Spermophilus), and rabbits (sylvilagus). Amongst the reptilian prey taken by this snake, Spiny lizards(Sceloporus), racerunners(Cnemidophorus), and rattlesnakes(Crotalus). It is a significant predator of nesting ground birds, and has been known to constrict multiple nestlings in a single event. Mammals such as pocket gophers and white footed mice are often taken by the gopher snake in their own burrows, in which they are forcefully pushed against the walls of the burrows until they expire{1,4,5}.

Reproduction
Mating occurs in the beginning of the spring, around April or may. After about 50 days of incubation, the eggs will hatch. Clutch size is dependant on the size of the maternal female, with smaller females laying subsequently smaller clutches. A typical clutch numbers 11-16, numbering as little as 8 or as many as 26. the young animals will stay in the burrows the females layed their eggs in until their first shed, and are independant as soon as they hatch{6}. A study published in 2008 found that hatchlings measured 32cm(12.5in) in snout-vent length, and will double in size in their first year{3}.

References
{1}Rodríguez‐Robles, Javier A. "Feeding ecology of North American gopher snakes (Pituophis catenifer, Colubridae)." Biological Journal of the Linnean Society 77.2 (2002): 165-183.
{2} RodrÍguez-Robles, Javier A. "Home ranges of gopher snakes (Pituophis catenifer, Colubridae) in central California." Copeia 2003.2 (2003): 391-396.
{3} Iverson, John B., Cameron A. Young, and Thomas S. Akre. "Body Size and Growth in the Bullsnake (Pituophis catenifer sayi) in the Nebraska Sandhills." Journal of Herpetology 42.3 (2008): 501-507.
{4}Werler, John E., and James R. Dixon. Texas snakes: identification, distribution, and natural history. University of Texas Press, 2010.
{5} Breckenridge, Walter J. Reptiles and amphibians of Minnesota. U of Minnesota Press, 1944.
{6} Wright, Jonathan D. "Bullsnake, Pituophis catenifer sayi, nesting biology in Alberta." The Canadian field-naturalist 122.2 (2008): 138-141.

[Ceratodromeus]

Here is a very cool study on the size of various gopher snake subspecies and their populations

[Ceratodromeus]

Record of a 2.667m bull snakes, one of the few validated animals of this length -- note taken from an edition of the 2007 Herpetological review
"The Eastern Indigo Snake (Drymarchon corais
couperi) has been heralded as the longest native snake in the United
States, having been documented to reach 2629 mm TL (Boundy
1995. Bull. Chicago Herpetol. Soc. 30:109–122). Although Dixon
(1952. Copeia 1952:193) reported a bullsnake measuring “9ft”
(2745 mm), he took this measurement from a skin and not a whole
animal (J. Dixon, pers. comm.). In June 1999 one of us (AM)
collected a Pituophis catenifer near Loma Alta (Val Verde County,
Texas, USA) that measured 2667 mm TL on 12 October 2001
after being kept and fed in captivity for ca. 2 years (Fig. 1). This
specimen represents a new record for the longest native snake in
the United States and extends the record length for the genus
Pituophis by 127 mm (Boundy, op. cit.). A voucher image of this
snake has been deposited in the Texas Natural History Collection
(TNHC 65425)."

[Ceratodromeus]

Neat article from 1926 on the bull snake's predatory habits with pocket gophers

[Ceratodromeus]

BODY SIZE AND SEXUAL SIZE DIMORPHISM OF BULLSNAKES (PITUOPHIS CATENIFER SAYI) IN WISCONSIN, USA
Abstract
Many studies exist on the evolutionary significance of sexual size dimorphism (SSD) in reptiles. Yet, this
phenomenon has received little attention in members of the snake Genus Pituophis. I investigated if SSD occurs in
Bullsnakes (Pituophis catenifer sayi) sampled at a site in southwestern Wisconsin, USA, by analyzing adult length and
calculating the Sexual Dimorphism Index (SDI) for individuals encountered from 2003–2005. I found that male length in
the population I studied was statistically larger than female length, which was previously unknown in this group of
snakes. Where possible, I also calculated SDI for sizes reported by other studies on members of this genus. The
calculated SDI had a male bias in 75% of these other studies. The male bias I found for my sample was greater than the
values I calculated for other published reports on Pituophis species and subspecies.

"Although some sources report that this species matures
from 90–96 cm total body length (TBL; reviewed by
Ernst and Ernst 2003), most snakes found in my research
(75%) had SVL measurements of ≥ 120 cm, and I
considered snakes of this size at my site as adults.
Because my goal was to report SVL and SDI among
regions in adults only, I included only individuals
reported to be over 100 cm in SVL from Stull (1940),
but included smaller individuals from other published
works if the authors categorized them as adults.
Although Stull (1940) includes tables of data from
individuals she analyzed, she did not report SVL for
these specimens, but total body length (TBL) and tail
length/TBL ratio. She also did not calculate means based
on snake sex. Therefore, I determined SVL for the
individual specimens she analyzed (multiplying TBL by
tail length/TBL ratio and subtracting the outcome from
TBL), and summarized the results by sex. Of the
subspecies reported by Stull (1940), I only summarized
data for those that have more recently had size data
published, for comparison.

Results
The number of snakes I encountered declined yearly.
I captured 26 unique adults in 2003, 20 in 2004, and six
in 2005. Male SVL (mean = 133.4 cm, SD = 13.2 cm)
was larger than female SVL (mean = 120.9 cm, SD =
10.7 cm; t = -3.872, df = 50, P < 0.001). I did not
statistically compare my data to the results of other
published reports because of differences in sample sizes
and methods of collection. However, the measurements
I recorded during my study were similar to these past
reports (Table 1).
The calculated SDI was male-biased in the P. c. sayi
that I sampled (-0.103). This bias was greater than
values calculated for all other studies, although sample
sizes varied (Table 1). Male-biased SDI values were
present in 12/16 cases (75%), although this bias was not
large in several of these instances. Female biases were
present in 4/16 (25%) of SDI values, but these were
generally weak."
www.herpconbio.org/Volume_4/Issue_3/Kapfer_2009.pdf