View source for Biology:Red-sided garter snake

{{Short description|Subspecies of snake}}
{{Subspeciesbox
| name = Red-sided garter snake
| image = File:Parietalis.JPG
| image_caption = 
| status =
| status_system =
| genus = Thamnophis
| species = sirtalis
| species_link = Common garter snake
| subspecies = parietalis
| authority =  (Say, 1823)
| synonyms = ''Coluber parietalis'' <small>Say, 1823</small>
}}

The '''red-sided garter snake''' ('''''Thamnophis sirtalis parietalis''''') is a [[Biology:Subspecies|subspecies]] of the [[Biology:Common garter snake|common garter snake]], in the subfamily [[Biology:Natricinae|Natricinae]] of the family [[Biology:Colubridae|Colubridae]].<ref name="Canadian Herpetological Society/Société d'Herpétologie du Canada - Red-sided Gartersnake">{{cite web |title=Red-sided Gartersnake |url=https://canadianherpetology.ca/species/species_page.html?cname=Red-sided%20Gartersnake |website=Canadian Herpetological Society |access-date=June 15, 2023}}</ref> This slender [[Biology:Subspecies|subspecies]] of natricine [[Biology:Snake|snake]] is indigenous to [[Earth:North America|North America]] and is one of the recognized subspecies of ''Thamnophis sirtalis''.<ref>{{Cite book |last=Rossman |first=Douglas Athon |title=The Garter Snakes: Evolution and Ecology |publisher=University of Oklahoma Press |year=1996 |isbn=978-0806128207}}</ref><ref>{{NRDB species |genus=Thamnophis |species=sirtalis }}</ref> This subspecies is widely spread across northern United States and southern Canada.<ref name=":2" /><ref>{{cite web | url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.105584/Thamnophis_sirtalis_parietalis | title=NatureServe Explorer 2.0 }}</ref>

== Appearance ==
The red-sided garter snakes have an upper row of well-defined red spots, and lower row with patches of red color that smear on the dark area on either side of their back.<ref name=":12">{{cite book |last1=Rossman |first1=Douglas Athon |title=The Garter Snakes: Evolution and Ecology |date=1996 |publisher=University of Oklahoma Press}}</ref> These snakes have multiple yellow stripes present on their body. ''Thamnophis sirtalis parietalis'' is [[Biology:Sexual dimorphism|sexually dimorphic]], where females are usually larger than males.<ref name=":2">{{cite journal |last1=Crews |first1=David |author2=William R. Garstka |date=1982 |title=The Ecological Physiology of a Garter Snake |url=http://www.jstor.org/stable/24966731 |journal=Scientific American |volume=247 |issue=5 |pages=158–171 |doi=10.1038/scientificamerican1182-158 |jstor=24966731 |bibcode=1982SciAm.247e.158C }}</ref> The females can range from 18 to 24 inches in length, whereas males can grow up to 12 to 18 inches.<ref name=":2" /> The snakes of this subspecies are mainly non-venomous.<ref name=":14">{{cite thesis |last1=Friesen |first1=C. R. |title=Patterns and mechanisms: Postcopulatory sexual selection and sexual conflict in a novel mating system |type=PhD thesis |year=2012 |url=https://ir.library.oregonstate.edu/downloads/m900nw80t |publisher=Oregon State University }}</ref>

== Phenology and habitat use ==
Winter temperatures near their habitat are very harsh and sometimes even drop below zero.<ref name=":9">{{cite thesis |last1=Thinesen |first1=Pamela Kay |date=1989 |title=Seasonal trailing behavior and corticosterone levels in male red-sided garter snakes (''Thamnophis sirtalis parietalis'') |type=MSc thesis |publisher=Portland State University |series=Dissertations and Theses |volume=3916 |doi=10.15760/etd.5800|doi-access=free }}</ref> During low temperatures in fall and winter, tens of thousands of male and female red-sided garter snakes [[Biology:Hibernation|hibernate]] together, in a shared underground communal den, for about eight months each year to protect themselves from cold weather and predators.<ref name=":4">{{cite journal |last1=Lincoln |first1=Julianna M., Megan L. Barlowe, Holly R. Rucker, M. Rockwell Parker. |title=Reconsidering Reproductive Patterns in a Model Dissociated Species, the Red-Sided Garter Snake: Sex-Specific and Seasonal Changes in Gonadal Steroidogenic Gene Expression |journal=Frontiers in Endocrinology |year=2023 |volume=14 |page=1135535 |doi=10.3389/fendo.2023.1135535 |pmid=36992803 |pmc=10040831 |doi-access=free }}</ref><ref name=":7">{{cite journal |last1=Lutterschmidt |first1=Deborah I. |date=2012 |title=Chronobiology of reproduction in garter snakes: Neuroendocrine mechanisms and geographic variation |journal=General and Comparative Endocrinology |volume=176 |issue=3 |pages=448–455 |issn=0016-6480 |doi=10.1016/j.ygcen.2011.12.015|pmid=22210163 }}</ref><ref name=":8">{{cite journal |last1=Mason |first1=Robert T., Richard Shine, Tracy Langkilde. |title=Courtship Tactics in Garter Snakes: How Do a Male's Morphology and behavior Influence his mating success |url=https://www.sciencedirect.com/science/article/pii/S000334720300366X |journal=Animal Behaviour|year=2004 |volume=67 |issue=3 |pages=477–483 |doi=10.1016/j.anbehav.2003.05.007 |s2cid=4830666 }}</ref> When the temperature rises around 25&nbsp;°C, it leads to the emergence of these snakes from their dens and triggers mating behavior.<ref name=":2" /><ref name=":10">{{cite journal |last1=Lutterschmidt |first1=Deborah I., Robert T. Mason |date=1 October 2009 |title=Endocrine mechanisms mediating temperature-induced reproductive behavior in red-sided garter snakes (''Thamnophis sirtalis parietalis'') |journal=Journal of Experimental Biology |volume=212 |issue=19 |pages=3108–3118 |doi=10.1242/jeb.033100|pmid=19749103 |s2cid=35337853 }}</ref> Since food or water is not available close to dens, the snakes migrate to feeding grounds after mating.<ref name=":2" /> In summer, the snakes move to mossy or marshy areas where they look for food.<ref name=":9" /> Adult snakes feed only for 2 to 3 months during summer, whereas the young ones feed till the start of winter.<ref name=":12" /> The adult primarily feed on ranid and [[Biology:Wood frog|wood frog]]s, and occasionally on mice and [[Biology:Vole|vole]]s.<ref name=":9" /><ref name=":12" /> The young snakes mostly feed on earthworms.<ref name=":12" /> Soon after feeding, close to the end of summer, the adult snakes return to their dens for winter hibernation.<ref name=":2" /> The young snakes, around one-year-old, spend more time in marshy areas to find food before the winter temperatures arrive and hibernate there as their small size makes them unnoticeable to predators.<ref name=":9" /> During hibernation, the energy stored from summer feeding is used for body growth and maintenance to survive in subzero temperatures for months.<ref name=":11">{{cite journal |last1=Whittier |first1=Joan M. |author2=David Crews |date=1990 |title=Body Mass and Reproduction in Female Red-Sided Garter Snakes (''Thamnophis sirtalis parietalis'') |url=http://www.jstor.org/stable/3892907 |journal=Herpetologica |publisher=JSTOR |volume=46 |issue=2 |pages=219–226 |jstor=3892907 }}</ref>

== Reproduction ==
In red-sided garter snakes, the breeding season usually begins in early spring and lasts for about a month.<ref name=":4" /> These snakes exhibit a [[Biology:Polygyny in animals|polygynous]] mating system, which means that males mate with multiple females each season.<ref name=":0">{{cite journal |last1=Whittier |first1=Joan M., Robert T. Mason, David Crews. |date=1985 |title=Mating in the Red-Sided Garter Snake, ''Thamnophis sirtalis parietalis'': Differential Effects on Male and Female Sexual Behavior |url=http://www.jstor.org/stable/4599775 |journal=Behavioral Ecology and Sociobiology |volume=16 |issue=3 |pages=257–261 |doi=10.1007/BF00310989 |jstor=4599775 |s2cid=33478759 }}</ref> During the mating season, male snakes form a mating ball near the dens and court females as they emerge.<ref name=":2" /> Each female is courted by hundreds of males upon emergence.<ref name=":1">{{cite journal |last1=Garstka |first1=William R. |author2=Brian Camazine |author3=David Crews |date=1982 |title=Interactions of Behavior and Physiology during the Annual Reproductive Cycle of the Red-Sided Garter Snake (''Thamnophis sirtalis parietalis'') |url=http://www.jstor.org/stable/3892366 |journal=Herpetologica |volume=38 |issue=1 |pages=104–123 |jstor=3892366 }}</ref><ref name=":2" /> After mating, males and females move to mossy summer grounds where they find food and water and birth the offspring.<ref name=":9" /> These snakes are viviparous and can birth about 30 young ones in one mating season.<ref name=":2" /> Gestation period is about 3 to 4 months, and the young ones reach sexual maturity at 1.5 or 2 years of life.<ref name=":9" /> In this species, the offspring are usually born before the adults re-enter winter dormancy, and immediately after birth, adult male and female snakes migrate back to their dens and re-enter hibernation in early fall before the temperature falls.<ref name=":2" /><ref name=":9" />

The reproductive system of male snakes includes testicles, epididymis, vas deferens, [[Biology:Hemipenis|hemipenes]], and renal sex segment.<ref name=":2" /> Testes produce sperm that are transported by epididymis to the vas deferens, which then transfer the sperm to hemipenes. These snakes have a double penis with one testis supplying seminal fluid to each hemipenis.<ref name=":2" /> Hemipenes are saclike organs that facilitate sperm transfer to the female. During winter, the segment of the vas deferens is used for sperm storage.<ref name=":2" /> The function of the renal sex segment is to produce copulatory pheromones and the granules for formation of a copulatory plug.<ref name=":13">{{cite journal |last1=Shine |first1=Richard |author2=M. M. Olsson |author3=R. T. Mason |date=July 2000 |title=Chastity belts in gartersnakes: the functional significance of mating plugs |journal=Biological Journal of the Linnean Society |volume=70 |issue=3 |pages=377–390 |doi=10.1111/j.1095-8312.2000.tb01229.x|s2cid=4843692 |doi-access=free }}</ref><ref name=":2" /> The female reproductive system consists of ovaries, an oviduct, and cloaca. The ovaries and oviducts are long due to the streamlined body of the snake. Multiple follicles (eggs) are present on the elongated ovaries. After mating, it takes up to 6 weeks for sperm to travel through the oviduct and reach the developing follicles in the ovaries.<ref name=":2" />

=== Pre-copulatory behavior ===
The behavior and physiology of red-sided garter snakes is heavily influenced by seasonal changes in the environment.<ref name=":1" /> Temperature is one of the most crucial factors in regulating the life cycle of this species.<ref name=":7" /> During mating season, males emerge first, all together in big groups, whereas females emerge singly or in small groups around 1 to 3 weeks after the emergence of males.<ref name=":7" /><ref name=":1" /> When females start to emerge, males begin to form mating balls where they gather around at the opening of the communal dens and start courting the females as soon as they emerge from dormancy.<ref name=":2" /> The courtship from males can continue from minutes to hours, but due to vigorous courting from males, females typically mate within 30 minutes after emerging.<ref name=":0" /><ref name=":2" />

==== Mate selection and courtship ====
In ''T. s. parietalis'', mating is largely based on the courtship tactics of males.<ref name=":8" /> Males prefer to mate with females who are unmated so they check females for any evidence of previous mating by studying their pheromonal trails for presence of copulatory pheromones or a copulatory plug by tongue-flicking in female cloaca and chin-rubbing to transfer pheromones from skin or cloaca to [[Biology:Vomeronasal organ|vomeronasal organ]] to determine her mating status.<ref name=":1" /><ref name=":2" /><ref name=":5">{{cite journal |last1=O'Donnell |first1=Ryan P. |author2=Neil B. Ford |author3=Richard Shine |author4=Robert T. Mason |date=October 2004 |title=Male Red-Sided Garter Snakes, ''Thamnophis sirtalis parietalis'', Determine female mating status from pheromone trails |url=https://www.sciencedirect.com/science/article/pii/S000334720400226X |journal=Animal Behaviour |volume=68 |issue=4 |pages=677–683|doi=10.1016/j.anbehav.2003.09.020 |s2cid=28192328 }}</ref> Males also display a preference for larger females with longer snout-vent length than smaller females.<ref name=":1" /><ref name=":6">{{cite journal |last1=Hawley |first1=Alexander W. L. |author2=Michael Aleksiuk |date=1976 |title=Sexual Receptivity in the Female Red-Sided Garter Snake (''Thamnophis sirtalis parietalis'') |journal=Copeia |volume=1976 |issue=2 |pages=401–404 |doi=10.2307/1443979|jstor=1443979 }}</ref> Increased female body length indirectly correlates to higher sexual receptivity as longer females have higher follicular development, which indicates increased receptivity.<ref name=":6" />

When a male finds a female attractive, male shows increased frequency of tongue-flicking, chin pressing, tail searching, body contractions, caudocephalic waving, and attempts to align his body and cloaca to that of females to increase his mating possibility.<ref name=":1" /><ref name=":8" /> However, as the sex ratio during emergence is highly male-biased, it is possible that multiple males court the same females together.<ref name=":2" /> This raises [[Biology:Intrasexual competition|intrasexual competition]] between males and results in male-male combat to secure the mate where males try to keep other males away from the females by ‘tail wrestling’ in which they insert their tails between the female and other courting males to force them off.<ref name=":3">{{cite journal |last1=Friesen |first1=Christopher R. |author2=Emily J. Uhrig |author3=Mattie Squire |author4=Robert T. Mason |author5=Patricia L. R. Brennan |date=2014 |title=Sexual Conflict over Mating in Red-Sided Garter Snakes (''Thamnophis sirtalis'') as Indicated by Experimental Manipulation of Genitalia |journal=Proceedings of the Royal Society B: Biological Sciences |volume=281 |issue=1774 |page=20132694 |doi=10.1098/rspb.2013.2694|pmid=24225467 |pmc=3843848 }}</ref><ref name=":8" /> Larger males with uninjured basal spine are benefited in such combats as they have longer tails which help them push off smaller males easily.<ref name=":8" /> Male who manages to keep his cloaca aligned with female the longest, reaches intromission.<ref name=":1" />

However, female snakes exhibit no preference while choosing a mate. Females do not play active role in courtship or compete for mates, however they do play an important role during intromission and [[Biology:Copulation (zoology)|copulation]].<ref name=":1" /><ref name=":6" /> After the male red-sided garter snake performs courtship behavior, if the female is sexually receptive, she remains steady, breathes rapidly, lifts her tail and gapes her cloacal opening.<ref name=":1" /> However, if she is unreceptive, she will reject the advances by strongly vibrating her tail and moving away from the courting males.<ref name=":1" />

=== Mating ===
During intromission, the male attempts to roll up the female's tail with his tail, aligning his cloaca with the female, and widens her cloaca by attaching the hooks at the base of hemipenes to cloacal scales for locking their cloacas together.<ref name=":1" /><ref name=":2" /> Then males insert one of their hemipenis bases into the female cloaca and start sperm transfer.<ref name=":3" /> After sperm transfer, males deposit a thick translucent gelatinous [[Biology:Mating plug|copulatory plug]] in the female cloaca that seals the cloaca by attaching the jelly-like substance to the cloacal wall.<ref name=":0" /><ref name=":1" /><ref name=":13" /> Average copulation lasts about 15 to 17 minutes, of which eight or more minutes are dedicated for sperm transfer and 2 to 5 minutes for the transfer of plug granules from the renal sex segment that aids in formation of mating plugs.<ref name=":13" />

=== Post-copulatory behavior ===
[[Philosophy:Sperm competition|Sperm competition]] among males is induced due to copulatory plug, as the primary function of the plug is to prevent re-mating in females by maintaining a reproductive barrier that blocks the female cloacal opening for about 72 hours after mating.<ref name=":0" /><ref name=":13" /><ref name=":14" /> Around that time, most females either become unreceptive or start migrating to feeding grounds immediately after mating to avoid any injury or suffocation due to the mass gathering of males, who stay at dens till the end of breeding season.<ref name=":2" /><ref name=":15">{{cite journal |last1=Shine |first1=Richard |author2=Ben Phillips |author3=Tracy Langkilde |author4=Deborah I. Lutterschmidt |author5=Heather Waye |author6=Robert T. Mason |date=July 2004 |title=Mechanisms and consequences of sexual conflict in garter snakes (''Thamnophis sirtalis'', Colubridae) |journal=Behavioral Ecology |volume=15 |issue=4 |pages=654–660 |doi=10.1093/beheco/arh058|doi-access=free }}</ref><ref name=":13" /> Along with mate-guarding the females, mating plugs also play an important role in initiating transfer of recently deposited sperm, evacuating stored sperm in the oviduct from previous matings, preventing sperm leakage, and acting as antiaphrodisiac in females.<ref name=":14" /><ref name=":0" /> After copulation, female attractiveness reduces due to seminal fluid and plug granules ejaculated in the female oviduct, which alters female pheromones that determine their attractiveness and receptivity<ref name=":13" /> Fewer males court these females to minimize the time spent on courting females who are not receptive as these changes can be determined by the female's pheromonal trails from miles away.<ref name=":5" /><ref name=":13" /> Female attractiveness decreases due to the presence of copulatory pheromones rather than changes in sex-attractiveness pheromones. The duration of release of copulatory pheromones coincides with the duration of a copulatory plug.<ref name=":5" />

=== Sexual conflict ===
In ''T. s. parietalis'', males prefer to have a longer copulatory duration for maximal sperm transfer and formation of a copulatory plug which aids in mate-guarding the female. If copulation lasts longer, males can produce larger plugs to reduce re-mating in females.<ref name=":3" /> However, if the quality or quantity of sperm transfer and copulatory plug is not adequate, the frequency of re-mating increases.<ref name=":16">{{cite journal |last1=Friesen |first1=C.R. |author2=Kerns, A.R.  |author3=Mason, R.T. |date=2014 |title=Factors influencing paternity in multiply mated female red-sided garter snakes and the persistent use of sperm stored over winter |journal=Behavioral Ecology and Sociobiology |volume=68 |issue=9 |pages=1419–1430|doi=10.1007/s00265-014-1749-0 |s2cid=253819264 }}</ref><ref name=":14" /> Copulatory plug mass is also influenced by male body size, female body size, and the number of prior mating in that season.<ref name=":13" /> However, females prefer shorter copulation to prevent injury to their reproductive tract, suffocation, exhaustion, and risk of predation.<ref name=":3" /><ref name=":15" /><ref name=":14" /> Female genitalia often bleeds during and after copulation as penetration of the basal spine harms cloacal tissues while locking genitals.<ref name=":3" /> To shorten the copulatory period, female snakes perform axial rotation and roll their body to disturb cloacal alignment with males. They also use vaginal muscles and cloacal tissues to force males away.<ref name=":3" /> Females also avoid large mating aggregations and prefer dens with fewer male pheromones to avoid distress or death due to exhaustion or forcible insemination.<ref name=":15" /><ref name=":14" /> Females also display post-copulatory sexual selection by re-mating or using sperm stored from the prior mating season, which increases sperm competition. It is common in red-sided garter snakes to have multiple paternity of offspring mainly by using stored sperm.<ref name=":16" />

==References==
{{Reflist}}

{{Taxonbar|from=Q15843100}}

[[Category:Thamnophis|sirtalis parietalis]]

{{Sourceattribution|Red-sided garter snake}}