Milk Snake Lampropeltis triangulum
by Jeff LeClere
PROTECTED. It is illegal to kill or collect this species by law in Iowa. Milk snakes are common, but since they are very secretive, they are seldom seen.
The milk snake is a medium sized Iowa snake that is 24 to 52 inches in length, but quite often maintains a slender build. It is nonvenomous. Although this snake’s blotched pattern remains consistent, its general coloration is quite variable. Some specimens can be beautifully light colored, having a light gray or brown ground color and bright to rusty red body blotches. Others can look a lot like fox snakes having an overall brown coloration. Still, others can be a dark gray with little or no difference in color between the ground color and blotches, only the black borders (which are always present) indicate the presence of blotches.
There is an alternating row (sometimes two) of lateral spots on the sides. These vary in size, but are never as big as the dorsal blotches. The belly is white with clusters of black checkers scattered randomly about the venter. Often there is a pink or peach wash to the general ventral coloration. There is a light V or Y marking at the back of the head, but this is sometimes replaced by a light spot. The snout is usually white. The scales are smooth and the anal plate is single.
Two subspecies of milk snake are found in Iowa, the red milk snake, L. t. syspila, and the eastern milk snake, L. t. triangulum. The red milk snake is usually brightly marked. It differs from the eastern milk snake in distribution and that it has a light ground color with bright red blotches. These blotches are large and extend down on the sides almost to the ventral scales. This results in the reduction in the size and number of the lateral spots.
The eastern milk snake was basically described in the description section. It is much more drab in coloration than the red milk snake and has smaller dorsal blotches which make the lateral spots larger and more numerous. These subspecies meet and intergrade heavily in eastern Iowa and surrounding areas. Intergrade specimens share characteristics of both subspecies.
A few specimens from northwestern Iowa appear to have genetic influence from the western forms of L. triangulum (most likely L. t. multistriata). These intergrade snakes have a large amount of black on top of the head, a gray ground color, and orangish dorsal blotches. An example is the photograph showing the intergrade from Woodbury County (above). I would be interested in pictures from milk snakes from this area. A larger sample size is needed to determine the extent of these intergrades in northwestern Iowa.
Milk snakes are found statewide in Iowa. The most pure eastern milk snakes can be found in northeastern Iowa, and the most pure red milks are found in the western half of Iowa. The others are intergrades between the two subspecies.
Rocky hillsides provide the favored habitat in Iowa, at least that is where they are most often seen. Farmlands, grasslands bordering woodlands, and rock outcroppings, especially near waterways, are used. Milk snakes are also found in woodlands and in the loess hills, but here they are rarely discovered unless they are found hit on the road or crossing a trail.
Milk snakes are diurnal in the spring and fall becoming largely nocturnal in summer. They are very secretive and are rarely found in the open. They spend much of their time hiding beneath logs, rocks, boards, bark, and other debris. Only on a few occasions have I observed milk snakes sunning in the open. Occasionally, they may climb in search of food or to escape severe flooding. My cousin found a red milk (nice large, bright, red blotches with yellow interspaces) in Johnson County swimming into shore during a flood. There were many trees about 20 meters away from shore. This was undoubtably where the snake came from.
Milk snakes endure many temperature extremes hiding under tin or rocks in hot weather when other species of snakes are underground, or hiding beneath rocks or boards with water or mud under them. Wild caught milk snakes can look extremely worn having many scars, skin lesions, (especially before a shed) or stub tails.
This snake is active from April to September. Most milk snakes move away from their rocky outcropping or mammal burrow hibernaculums to farms and grasslands with suitable food and cover during the summer. A few remain near their overwintering spots, however.
Mating takes place in spring or early summer. The female lays about 10 eggs in an area selected for its high humidity and warmth. Incubation lasts from 28 to 39 days. In the fall, the young milk snakes hatch from their eggs. They are 5 to 10 inches at hatching and have the most spectacular coloration they will ever have. They are bright white or gray with rich pure red blotches. Milk snakes are usually apt to coil, strike and bite when captured, especially during cold weather. They strike with a short, forced hiss and try to quickly slither away and under cover when they get the chance. Even after they are picked up, they may casually turn and chew on fingers or the arm of the person holding it. They also vibrate their tails and release musk.
Milk snakes feed on a wide variety of animals including mice, reptiles, amphibians, invertebrates, reptile eggs, birds and birds eggs. They are a type of kingsnake and will consume venomous snakes when they chance upon them. They are at least partially immune to the venom of the venomous snakes in their range and many venomous serpents will use defensive tactics other than biting to protect themselves from kingsnakes. Young snakes comprise a large portion of a baby milk snakes diet, but they are not found to be the most significant food item for adults (Breckenridge, 1944). Adults consume mainly rodents. Milk snakes are constrictors and kill their food by suffocation. Milk snakes are so named because it was once believed that these snakes would enter barns and steal milk from cows. This is false; snakes only drink water. They would become sick if they were to drink cows milk. Snakes also have sharp teeth; no cow would stand still for that! The milk snakes were in the barns actually helping the farmers by looking for rodents to eat.