californiae - California kingsnake nigrita - Mexican black kingsnake splendida - desert kingsnake nigra - black kingsnake holbrooki - speckled kingsnake getula - eastern (chain) kingsnake floridana - Florida kingsnake sticticeps - outer banks kingsnake
Their range extends across the continental United States and northern Mexico.3 Kingsnakes are robust constrictors known for their immunity to venomous snakes that inhabit their range. They have a brown to black background covered with a yellow pattern that may be speckled, striped or banded. Some specimens are totally black. Albinos have been propagated in captivity. Adults average 80 to 145 cm in total length with exceptional specimens reaching 170 cm.4 Kingsnakes rank among the most popular of pets for many reasons. They have tractable dispositions, voracious appetites and breed readily if sound husbandry techniques are practised. Most can be sustained on a diet consisting solely of mice. In the wild they consume small rodents, frogs, lizards, eggs and other snakes.5
Due to their cannibalistic tendencies kingsnakes should be housed separately except when paired for breeding. Depending on their size adults can be housed in 10 - 15 or 20 gallon tanks. A secure lid is a must; screen tops fastened with clamps work well. These reptiles are secretive by nature; therefore, a hidebox is recommended for their well being. There are, however, individuals that will never use a hidebox. A water bowl large enough for total body immersion is necessary, as they need frequent access to water. Water bowls should be cleaned every three to five days; cages and furnishings should be disinfected every four months using 1/4 cup of bleach added to one gallon of water.6 Snakes should be checked daily and cages cleaned as soon as any waste material is observed. Chlorhexadine (Nolvasan Solution, Aveco Co, Fort Dodge, IA 50501) diluted to three ounces per gallon of water works well and is non-toxic to reptiles. Newspaper is an excellent substrate, serving to keep the cage dry and permitting early detection of urates and faecal waste. Kingsnakes are terrestrial in habit and so a climbing branch is not necessary. Heat should be provided on one side of the tank from the bottom so that a temperature gradient is created ranging from 25-30 deg.C (75-85 deg.F) with a drop of five degrees at night.6 Ultraviolet rays are not needed; however, daytime light for nine to 12 hours is recommended to stimulate normal behavior.3
Kingsnakes are active diurnal predators with a high metabolic rate. At the preferred temperature range transit time of ingesta is approximately 72 hours (personal observation). Adults should be fed no more than once weekly with one to three mice at each feeding depending on the size of the snake and mice. Most kingsnakes readily eat thawed mice; offering a freshly killed mouse monthly may be done to make certain that the snake is receiving all its vitamins. Although some owners enjoy watching their reptiles eat live food regularly, there are several reasons to offer dead prey. The chance of injury to the snake is minimised and the risk of parasitism is significantly reduced.7
Shedding frequently depends on growth rate; juveniles may shed every two to four weeks, while adults will shed approximately four times a year.8
Maintaining accurate records is frequently an overlooked aspect of herpetoculture. Each snake should have an index card noting date of birth, source of acquisition, periodic weights, shedding frequency and feeding schedule. This permits the keeper to maintain a high standard of daily care, anticipate breeding/hibernation cycles, and furnish the veterinarian with an accurate history in the event that illness occurs.
Kingsnakes normally go off their feed in the fall and become restless. This is in anticipation of hibernation. Food should be withheld three weeks prior to cooling with the temperature slightly elevated to be certain there is no ingesta in the intestinal tract. This will minimize the risk of food decomposition in the gut during hibernation.3 The snakes are cooled from December first through March first of each year. This is done for two reasons: A) the cycle mimics their natural biorhythm and B) cooler temperatures stimulate the hypothalamic-pituitary axis required for oogenesis and spermatogenesis in the spring. 9 Snakes should not be suddenly cooled, but rather a gradual temperature decrease should be augmented during a two-week period prior to hibernation. They are then place in a darkened secluded area and maintained at a temperature range of 10-15 deg.C (50-55 deg.F).10 Water must be provided during this period. Houses tend to get dry during the winter and so one must be on guard for dehydration. Checking the snakes every two weeks is recommended. Kingsnakes will stay active during this and continue to shed, drink and pass urates. Those individuals that are not in peak condition should not be cooled so that they will continue to feed. Any health problems should be treated appropriately. After hibernation the snakes should be gradually warmed during a two-week period until the proper ambient temperature is attained.
Proper sexing is essential to a sound breeding program. This is performed by gently inserting into the caudal cloaca an appropriately sized sexing probe that has been lubricated with tap water. Many sterile lubricants have been shown to be spermicidal.11 Females probe to a depth of approximately two subcaudal scales while males will probe to eight or more subcaudals.3 Most kingsnakes are bred at two years of age and double-clutching is often attempted.4 It has been recommended to take the males out of hibernation two weeks prior to the females so that they have a chance to gain some weight prior to the breeding season.12 Male kingsnakes become anorexic when they sense receptive females and may refuse food for up to two months resulting in a significant amount of weight loss. If they are parasite-free and have access to water there should not be any problems. After the breeding season, males resume feeding.
Females are usually ravenous afterhibernation, taking their first meal within one week after warming. Food should be offered every three to five days to supply nutrients needed for vitellogenesis (yolk formation).12 Two to three weeks later the female will have her preovulatory shed. After this occurs she is placed with the male to observe for courtship behavior. The female's shed skin may also be place in the cage because it contains pheromones to attract males.3 Breeders either leave the paired snakes together continuously or reintroduce the female to the male every three days.13 For more accurate breeding records the latter is recommended. An ovulating female can sometimes be gently palpated by allowing her to crawl between one's thumb and index finger. Developing follicles can be felt as "marbles on a string" or be visualized as a mid body swelling.3 If the snakes have been cycled properly and are compatible then copulation usually occurs shortly after the pair is placed together. In the wild, male kingsnakes have been observed engaging in combat behavior.5 This assures that the genes of the strongest individual are passed on to future generations. If a male does not show interest in a female, courtship may be stimulated by the addition of a shed skin from another male. At other times another male added to the pair is necessary to initiate copulation. If the female is ovulating the male will aggressively chase her, biting the head and neck area. He will then attempt to elevate her tail so as to align their vents prior to copulation. Once intromission has occurred rhythmic cephalo-caudal peristaltic ontractions begin. This may last from minutes to hours. Finally, the female will crawl away and the male will withdraw his hemipenis. Copulation may occur intermittently over a period of several weeks. When the snakes are fed it is best to separate them to prevent accidents while eating. After the male no longer shows interest in the female they are separated.
If the female becomes gravid, the posterior half of her body will become noticeably swollen within a week. In approximately four weeks she will have her prelaying shed and lay her eggs seven to ten days later.11 The eggs range in number from four to twenty depending on the subspecies. One cannot stress enough the importance of a suitable substrate where the female will oviposit. Moistened pine shavings, sphagnum, or peat moss work well. These can be placed in a hollow container and sides of the cage can be covered with a towel to offer seclusion. Restlessness generally precedes egg-laying. All the eggs should pass during a 24-hour period.1 As with other egg-laying snakes it is recommended that the eggs be removed from the cage being careful not to rotate them as this may damage the embryos.13 Some breeders place a dot on the top of each egg as a marker of polarity before removing them.11Once the eggs have adhered to each other they should not be separated, as the shells can be damaged. They are then incubated at a temperature of 26-28 deg.C (80-82 deg.F).4 I recommend using a commercial incubator (Hova-bator, GQF Manufacturing Co, Savannah, Ga 31498); it is reasonably priced and will maintain proper conditions regardless of fluctuating ambient temperatures. However, many herpetolculturists have had success with a variety of home-made and commercial models. Before being placed in the incubator the eggs are half-buried in a mixture of vermiculite and water in a two-to-one ratio by weight.14 Plastic shoe-boxes with holes made on top are used to house the eggs and vermiculite. After being placed in the incubator the eggs should be checked once weekly. If they start collapsing prematurely it means they are dehydrating, so more water must be added to the vermiculite.11 If they appear to be swelling excessively it means the water content is too high. Mold formation or brownish discoloration is a sign of infertility. If bad eggs are adhered to viable eggs, the former should not be removed from the clutch due to the risk of damaging the fertile ones.11
Hatching commences 60-70 days later with the neonates slitting the shells with an egg-tooth that is subsequently lost with the first shed.3 All the eggs should have pipped during a 48 hour period. For those that have not, a small slit may be made through the shell to facilitate neonatal emergence. The neonates may stay in their eggs for a few days absorbing the rest of the yolk before venturing out.15
Only remove the shells after they have been completely vacated. The new-born snakes should be separated immediately as they can be cannibalistic. Plastic sandwich containers work very well for the first few weeks of life. Each box should have a water container and paper towel as a substrate. Holes are made on the top of each box to allow for ventilation and prevention of excessive humidity. Some neonates will eat almost immediately after hatching while others will wait until after their first shed. Most can be started on pinkies; others may have to be tricked into eating by scent transferring using anoles, geckos or skinks.1 Once the neonates begin eating regularly (one to two pinkies per week), growth is rapid with sexual maturity being attained in two to three years. Breeders generally do not hibernate the young until they are yearlings.12 This is done to accelerate growth by allowing them to eat throughout the year. Life span in captivity has been recorded up to 33 years16
1 Markel, RG. 1990. Kingsnakes and
Milksnakes. TFH Publications, Inc., Neptune City, NJ, 47
Last Updated: February 19, 2007