The milk snake (Lampropeltis triangulum) is a species of nonvenomous snake belonging to the family Colubridae which can be found throughout the warmer parts of the Americas. The name “milk snake” comes from the urban legend that they drink the milk of cows. It is not anatomically capable of suckling from a cow’s udder, however; the myth likely originates from the fact that milk snakes will frequently take advantage of barns for habitat. Barns provide cool, shady environments where rodents may be found, and so are ideal places for the snake to live.
There are twenty-four subspecies of milk snake, at least one of which inhabits Isla Sorna:
- Lampropeltis triangulum abnorma: Guatemalan milk snake
- Lampropeltis triangulum amaura: Louisiana milk snake
- Lampropeltis triangulum andesiana: Andean milk snake
- Lampropeltis triangulum annulata: Mexican milk snake
- Lampropeltis triangulum arcifera: Jalisco milk snake
- Lampropeltis triangulum blanchardi: Blanchard’s milk snake
- Lampropeltis triangulum campbelli: Pueblan milk snake
- Lampropeltis triangulum celaenops: New Mexico milk snake
- Lampropeltis triangulum conanti: Conant’s milk snake
- Lampropeltis triangulum dixoni: Dixon’s milk snake
- Lampropeltis triangulum gaigeae: Black milk snake
- Lampropeltis triangulum gentilis: Central Plains milk snake
- Lampropeltis triangulum hondurensis: Honduran milk snake
- Lampropeltis triangulum micropholis: Ecuadorian milk snake
- Lampropeltis triangulum multistriata: Pale milk snake
- Lampropeltis triangulum nelsoni: Nelson’s milk snake
- Lampropeltis triangulum oligozona: Pacific Central American milk snake
- Lampropeltis triangulum polyzona: Atlantic Central American milk snake
- Lampropeltis triangulum sinaloae: Sinaloan milk snake
- Lampropeltis triangulum smithi: Smith’s milk snake
- Lampropeltis triangulum stuarti: Stuart’s milk snake
- Lampropeltis triangulum syspila: Red milk snake
- Lampropeltis triangulum taylori: Utah milk snake
- Lampropeltis triangulum triangulum: Eastern milk snake
Thus far, only one individual has been observed on Isla Sorna, and its entire body was not visible at the time; only its tail was recorded. Based on its locality, it is most likely one of the following: the Guatemalan, black, Ecuadorian, Pacific Central American, or Stuart’s milk snake. The tail coloration that has been observed suggests that the individual in question is probably an Ecuadorian, Pacific Central American, or Stuart’s milk snake; however, coloration between the subspecies can vary, and tricolor varieties are far from unknown in subspecies that are usually patterned differently in the wild.
Description
While there are twenty-four subspecies of milk snake, this particular one is identified by a base red color with black and yellow rings or bands. The yellow may be replaced by deep orange in some specimens, referred to as a “tangerine phase” snake. In some of the subspecies, the tail region may lack white or yellow bands; if a snake whose subspecies normally lacks said bands does possess them, it is referred to as a “hypomelanistic tricolor” snake. For example, the black milk snake is melanistic in the wild, having an almost completely black body. However, some breeds and populations of this subspecies can resemble the one witnessed on Isla Sorna in 1997, and these would be hypomelanistic tricolors.
Size varies based on subspecies, but in general, milk snakes grow between 20 and 60 inches (51 to 152 centimeters) long. Its body is covered in smooth, shiny scales. Many subspecies, including the one seen on Isla Sorna, exhibit a form of Batesian mimicry: they have evolved to resemble the highly venomous coral snake, which inhabits Latin America. This mimicry is designed to deter predators, which may mistake the nonvenomous milk snake for the coral snake. In milk snakes, the color patterning often appears as red, black, yellow, black, red; in some, the pattern has white instead of red. However, many subspecies exhibit wildly different color patterns and some are not mimics of any species of coral snake at all. Most do mimic some species of venomous snake, but the traditional means by which milk snakes can be told apart from the venomous species they mimic are not always reliable.
Growth
Hatchlings are approximately eight inches long, and are darker-colored than the adults.
The lifespan of most milk snake subspecies in the wild is around twelve years; in captivity, they have been known to live as long as twenty-one years.
Sexual Dimorphism
Sexual dimorphism is sometimes observed in milk snakes. The male often grows longer, but the female can be bulkier than a male of comparable size.
Habitat
Preferred Habitat
The milk snake prefers to inhabit warm environments, but is tolerant of cooler climates. It may be found in forests and other sheltered areas where shade and food are easy to come by; to avoid danger, it often hides in leaf litter, which is another feature that draws it to forests.
Some of the subspecies not found in Central America are known to inhabit prairies, rocky deserts, and other such open areas as well as more traditional woodland. Within Central America, it is an inhabitant of dense, wet forests.
Natural range
The extreme northernmost point where milk snakes may live is the border between the United States and Canada, with many sightings in Maine, British Columbia, and throughout the Great Plains region. In the south, it may be found all throughout the United States, Mexico, and other Central American countries all the way down into South America. The southernmost sightings are in Colombia and Ecuador, mainly to the west of the Andes Mountains.
Milk snakes are also found on a number of offshore islands throughout their range, mainly in the Caribbean Sea and the Gulf of Fernandez. They have been documented on Isla Sorna, favoring the wet interior of the island.
Introduced
Common in the pet trade for its easy care requirements, escaped or released milk snakes are not unknown throughout the world. Fortunately, they are not terribly popular outside the Americas (where they are an indigenous species) due to the difficulty in transporting them across the ocean, so invasive populations have not been documented.
Behavior and Ecology
Activity Patterns
These snakes are crepuscular, emerging at dawn and dusk to feed on small animals.
Diet and Feeding Behavior
Milk snakes generally prey on small rodents, amphibians, and reptiles, including lizards and snakes; they may prey on venomous snakes without any apparent difficulty and are also known to be cannibalistic. Small birds are also potential prey. They may also eat eggs. The juveniles, before they are large enough to kill vertebrate animals, feed on invertebrates such as slugs, insects, and worms.
Prey is killed by constriction, rather than biting; milk snakes are nonvenomous.
Social Behavior
Due to their cannibalistic tendencies, all milk snakes are solitary except when mating.
Reproduction
The milk snake is sexually mature at 18 months, and may lay three to eighteen white ovoid eggs at a time. Mating takes place between May and June. Eggs are laid under logs or in rotting vegetation starting in early June, and incubate for two months. They hatch in August or September. As with most snakes, the milk snake shows no parental care, and may even view its young as potential food if they do not vacate the area quickly enough.
Communication
Milk snakes are not known to vocalize, and communicate mainly by scent. As they are not social, their main forms of communication are to attract mates.
Ecological Interactions
They are not venomous, and will rarely bite if threatened; they usually employ other defense mechanisms first, such as attempting to flee or discharging a foul smell. Due to its small size, this snake would probably not be a threat to any de-extinct animals on Isla Sorna, and may instead be preyed upon by some carnivorous species such as Velociraptor and Compsognathus, which are found in the same habitat.
To avoid being eaten, most milk snake subspecies employ Batesian mimicry, which means they have evolved to resemble a threatening species. Many resemble coral snakes, which are highly venomous; this deters predators from attacking, as the predators are unwilling to take the risk of finding out whether this snake is venomous or not. Even so, when disturbed by humans or other animals, this reptile prefers to flee. This is likely what killed Dr. Robert Burke during the 1997 Isla Sorna incident; having been disturbed in the middle of the night when it would be sleeping, a milk snake fled into the nearest shelter it could find, which happened to be Dr. Burke’s shirt collar. This frightened the paleontologist to his death as he stumbled into the reach of a tyrannosaur.
While the snake was almost certainly consumed along with Dr. Burke during the incident, it is unlikely that an adult female Tyrannosaurus rex under normal conditions would prey on such a small animal intentionally.
Milk snakes prey on numerous small animals, and some have a resistance to the venom of other snakes. This enables them to prey on venomous snakes, as well as small animals such as insects, worms, slugs, lizards, snakes, frogs, rodents, and birds. They may also eat the eggs of small animals. All of these activities keep in check the populations of other animals in the ecosystem.
Cultural Significance
Symbolism
The milk snake is well-known for its use of mimicry to defend itself and is one of the best known examples of Batesian mimicry in Western cultures. It is commonly differentiated from the coral snake using the rhyme “Red on black and you’re okay Jack; red on yellow and you’re a dead fellow.” This is somewhat misleading, as not all milk snakes employ this particular color pattern, and some do not even mimic coral snakes at all.
Snakes in general are viewed negatively in many Western cultures, and the milk snake in European-American folklore is said to sneak into barns to drink milk from cows. In reality it does not, and cannot, do this. Reptiles do not even produce milk and so cannot digest it.
In Captivity
Milk snakes are often kept as pets, valued for their comparative ease of keeping and variety of attractive colors. Many breeders will specialize in particular color morphs, making plenty of them widely available. They are simple to satisfy in captivity with a medium-sized enclosure including vegetation. Rodents constitute a large amount of their diet in the wild, so they are usually fed rats and mice in captivity. Most experts recommend feeding them prepared food, such as freeze-dried rodents, rather than live food; this is because a live prey item may fight back, which can injure the snake.
This animal prefers cool and dark environments with plenty of hiding spaces. Shade makes it feel safe and comfortable, but it is an ectotherm, so it cannot be allowed to get too cold for too long. Some subspecies are better suited to cooler environments than others; those found in the United States are generally better cold-adapted than Central American subspecies. None are truly evolved for frigid weather, and are better kept in temperate or warm enclosures.
Like all snakes, it will periodically shed its skin, during which time it will be more vulnerable. In captivity, there are no predators to threaten it, but it will still be more nervous during this time. Extra care to keep its stress levels low will benefit it.
Science
Batesian mimicry is demonstrated very well (and in quite diverse forms) by this reptile, making it a good teaching tool in biology education. Many subspecies of milk snake have evolved over generations to resemble common venomous snakes in their environments, which helps scientists understand the evolution of American ecological systems over the past few million years.
Politics
The milk snake is listed as Least Concern by the International Union for Conservation of Nature. Its main threat is habitat loss, but it was historically collected in unsustainable numbers for the pet trade, depleting its wild population. Success at captive breeding has allowed their numbers in the wild to rise back up again without extensive regulation.
Milk snakes are sometimes incidental victims of the mass snake-killing programs in certain American states, since they are confused with venomous animals. Mass killings of snakes are ecologically devastating, but as most American politicians do not have an extensive understanding of biology, it is mostly considered an animal rights issue in the United States.
Resources
Since it is fairly small, the milk snake is usually not hunted for its pelt. Instead, it is popular in the reptile pet trade, and was historically collected from the wild in the Americas to sell to potential owners. The docile nature of this snake makes it one of the easier reptiles to keep, and its breeding patterns are well-studied which enables a viable market supply.
A predator of rodents, the milk snake is extremely useful for pest control. It prefers cool sheltered areas and is often found in barns, where it will eat rats and mice. As it is a carnivore, it does not feed on any farm crops, making it a highly efficient way to protect harvests.
Safety
Milk snakes are docile and rather skittish, and are more likely to flee and hide if disturbed. They will bite to defend themselves only when cornered, relying on their mimicry to fool predators into thinking they are venomous. Simply do not chase or harass any snakes you encounter and you will avoid being bitten. Since it is small and essentially harmless to humans, the milk snake is not a threat.
The real risk is mistaking a venomous snake for one of its harmless milk snake mimics. Usual means of differentiating the species may not always work, since milk snakes come in a wide variety of patterns and it can be difficult to distinguish them. In general, interacting with wild animals is inadvisable since they are unpredictable, so leave them alone should you encounter them. Only a snake expert should confirm whether a given snake is a harmless mimic or a genuinely venomous animal; amateurs should not take the chance. Coral snakes, for example, have highly potent venom that is fatal in hours. There were once coral snake antivenoms available in the United States, but the American companies that used to make them have ceased doing so in order to save on production costs.
Jurassic-Pedia would like to give special mention to the deceased American paleontologist Dr. Robert Burke, who died due to an overreaction to a milk snake encounter. The snake in question was disturbed by the InGen Harvester party during the 1997 Isla Sorna incident while it was sleeping in a small cave, and hid in the closest place it could find. That hiding place was Dr. Burke’s shirt collar, and upon finding it there the scientist panicked due to his fear of snakes; he stumbled directly into the jaws of a tyrannosaur as a result. Even if the snake had been venomous, flailing and stumbling around would not be a good way to avoid being bitten. Calmly remove any snakes that are too close to you by holding them right behind the head so they cannot bite, and avoid any dramatic movements, especially ones which place you in the mouth of an angry multi-ton theropod dinosaur.
Behind the Scenes
The role of the milk snake in The Lost World: Jurassic Park was originally planned to be filled by several giant tropical centipedes (Scolopendra sp.), which would have their venom glands removed before being used in the film. The multiple giant centipedes were ultimately replaced by a single milk snake, likely because the snake would be easier to handle, less expensive, and would not require any surgical modifications for its role. Centipedes still appear in this role in the film’s junior novelization and in some comic adaptations.
