Geographic Range
Baron's Green Racers are found in South America and have been collected from Northern
Argentina, Paraguay and Bolivia. The Gran Chaco region of Argentina, a semi-arid,
sparsely populated lowland, has been reported as the center of their range.
- Biogeographic Regions
- neotropical
Habitat
Baron's green racers are a strictly arboreal species and inhabit savannas, tropical
and subtropical forests.
- Habitat Regions
- tropical
- terrestrial
- Terrestrial Biomes
- rainforest
Physical Description
Baron’s green racers are a medium sized snake and can reach up to 2 m in length, making them the largest species within the genus Philodryas . They have a slender body, narrow head and relatively long tail. Green is the most common coloration among Baron’s green racers, however, blue and brown varieties may also be found. A brown variety inhabits the northern parts of Argentina and is known as Philodryas baroni var. fuscoflavescens . The eyes of Baron’s green racers are less than one third the snout length and have a round pupil. The snout often comes to a prominent point made of extending rostral scales which are more developed in males than in females, but do occur in both sexes. There are 21 or 23 rows of smooth, single-pitted scales. Some specimens display two longitudinal black lines which pass through the eyes laterally and extend from the rostrum through the anterior third of the body. The upper lip is white and the ventral body surface is often a greenish white. Baron’s green racers are opisthoglyphous, with their fangs located in the rear of the mouth.
There are several morphological features of Baron’s green racers which appear to be
well-adapted to these snakes’ habitat choice and activity patterns. A long tail and
slender body are common traits of arboreal snakes as these features allow for swift
and balanced movement through an arboreal habitat. Green racers are also well-camouflaged
amongst tree branches. Their green coloration is advantageous as it allows these diurnal
snakes to remain cryptic to both predators and prey. There is little published data
on sexual dimorphism in
P. Baroni
, however, closely related arboreal species such as
P. olfersii
display dimorphism in body size. Females of
P. olfersii
tend to have a larger body length than males, possibly to increase reproductive potential
while remaining slender enough to successfully navigate an arboreal habitat. Similar
patterns have been reported in
P. Baroni
by herpetoculturalists.
- Other Physical Features
- ectothermic
- bilateral symmetry
- venomous
- Sexual Dimorphism
- female larger
Reproduction
The mating system of Baron's green racers is not referenced in the literature, but
studies on related species have indicated that multiple mating events may occur within
one breeding season. Whether or not these mating events are monogamous, polyandrous,
polygynous or polygynandrous is unspecified.
Baron’s green racers are oviparous. Herpetoculturalists have reported that females
will produce greater than 20 eggs per clutch, but the average clutch size is around
10. Unfortunately there are currently no published field studies which broach the
topic of their reproductive cycle. Perhaps inferences can be drawn from a more frequently
studied arboreal relative that shares a home range with
P. baroni
,
P. olfersii
.
P. olfersii
have been reported to ovulate for roughly 3 months of the year between November-January,
but reproductive individuals of both sexes have been collected year round. Clutch
size in this species varied between 4 and 11 eggs, however, there may be potential
for multiple mating events and multiple clutches throughout the reproductive season.
Males experience a period of reproductive dormancy during the colder months of the
year. Baron's green racers return to communal nesting sites each year.
- Key Reproductive Features
- iteroparous
- year-round breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- oviparous
Females invest in resources for their eggs, but little additional information on parental investment is available in the literature.
- Parental Investment
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
No information on longevity in Baron's green racers is reported in the literature.
Behavior
Baron’s green racers are diurnal and peak activity has been reported in the warmer
and wetter months, especially in autumn. They are reported to be less aggressive than
other members of the genus
Philodryas
, but may still coil and strike repeatedly if threatened. If threatened, Baron's green
racers are also known to excrete a foul-smelling substance from the cloaca in defense.
Home Range
Home range size is not reported in the literature.
Communication and Perception
Like other lizards, Baron's green racers have keen eyesight that they use to capture prey. They also sense chemicals in the air with their tongues. Forms of communication are not reported in the literature for this species.
Food Habits
Baron's green racers are carnivorous and their diet mainly consists of arboreal frogs,
lizards, and small mammals. Both constriction and envenomation are used to subdue
prey items. Cannibalism of immature individuals by larger members of the species has
also been reported.
- Primary Diet
-
carnivore
- eats terrestrial vertebrates
- Animal Foods
- mammals
- amphibians
- reptiles
Predation
Baron's green racers are cryptically colored as their green coloration provides camouflage
in the foliage. There is no information available concerning the predators of
P. baroni
.
- Anti-predator Adaptations
- cryptic
Ecosystem Roles
No information is available regarding the ecosystem role of Baron's green racers, however, based on their diet it can be inferred that they are an important generalist predator.
Economic Importance for Humans: Positive
Baron's green racers have become popular in the exotic pet trade. They are owned and
bred by people all over the world.
- Positive Impacts
- pet trade
Economic Importance for Humans: Negative
While reportedly non-aggressive, Baron's green racers have bitten and envenomated
humans. No human deaths as a result from a green racer bite have been recorded but
bites should be considered medically significant and be treated by a medical professional.
The bite symptoms include pain, swelling, hemorrhaging, and lesions on the affected
area.
- Negative Impacts
-
injures humans
- bites or stings
- venomous
Conservation Status
Baron's green racers are considered least concern by the IUCN and are not on any lists of endangered or threatened animals.
Additional Links
Contributors
Taylor Schoen (author), Michigan State University , James Harding (editor), Michigan State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- rainforest
-
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- venomous
-
an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- year-round breeding
-
breeding takes place throughout the year
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- diurnal
-
- active during the day, 2. lasting for one day.
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- cryptic
-
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
- pet trade
-
the business of buying and selling animals for people to keep in their homes as pets.
- venomous
-
an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).
- carnivore
-
an animal that mainly eats meat
References
Boulenger, G. 1896. Catalogue of the Snakes in the British Museum . London: Taylor and Francis.
Hartmann, P., O. Marques. 2005. Diet and habitat use of two sympatric species of Philodryas (Colubridae), in south Brazil. Amphibia-Reptilia , 26: 25-31.
Leynaud, G., G. Reati, E. Bucher. 2008. Annual activity patterns of snakes from central Argentina (CĂłrdoba province). Studies on Neotropical Fauna and Environment , 43: 19-24.
Mesquita, P., G. Sa-Polidoro, S. Cechin. 2013. Reproductive biology of Philodryas olfersii (Serpentes, Dipsadidae) in a subtropical region of Brazil. Herpetological Journal , 23: 39-44.
Sanchez, M., A. Timoniuk, S. Marunak, P. Tiebler, O. Acosta, M. Peichoto. 2014. Biochemical and biological analysis of Philodryas baroni (Baron’s Green Racer; Dipsadidae) venom: Relevance to the findings of human risk assessment. Human and Experimental Toxicology , 33: 22-31.
2016. "Baron's green racer Philodryas baroni" (On-line). Accessed May 04, 2016 at http://www.hellabrunn.de/en/animal-dictionary/animals-a-z/barons-green-racer/ .
"Philodryas baroni Berg 1895" (On-line). Accessed May 02, 2016 at http://www.philodryas.com/indexENG.htm .
2015. "South American Green Snake" (On-line). Accessed May 04, 2016 at http://sfzoodocents.org/notebook/FactSheets/REPTILIA/SnakeSAGreen.pdf .