Leopard Gecko Breeding | Harems, Menopause, and More
Authored by Ron Tremper Leopardgecko.com
If you have a single male and you introduce an adult female gecko to the cage for breeding purposes, the first thing you may hear and/or witness is the male going through his tail vibration routine. When he recognizes the female by her odor or behavior, he will approach her tail, giving it a series of licks and small bites along its length, eventually biting the body. If the female is receptive she will stand perfectly still or display a tail lift, sometimes high on her legs, while the male moves up to the neck region, grasping her neck skin in his mouth while engaging in copulation. Don’t be concerned about the male restraining a female in this way; it is perfectly normal and natural. A successful mating takes only 2-3 minutes from start to finish and, because leopard geckos can store viable sperm for a number of months, fertile eggs can be produced up to nine months following a single mating. However, it is best to give females the opportunity to mate every 3-4 weeks during the breeding season to ensure the highest possible rate of fertility.
Years ago, many of us used a method whereby one male was placed with as many as 100 females on a continuous basis in large troughs with numerous warm hides. Over the last 30 years, the recommended ratio of females per male has decreased dramatically. Most successful breeders have learned that a maximum of 3-4 females per male (see photo) gives the best production rate per square foot of cage space. Increasing that ratio is self-defeating, resulting in decreased fecundity, and increased competition and stress amongst cage mates.
Even under the best circumstances a breeding group of 3-4 lizards will still need to be inspected weekly for signs of decline. It’s not uncommon to find one or two females who are losing weight due to the stress of competition, tail loss, or egg-laying. Such animals need to be separated and housed singly for several weeks, which often leads to their full recovery. One practice that helps reduce group stress is to remove the male from the females for the 3-4 month period of the year when it is not the breeding season. This gives females potential relief from overly attentive males and generally makes for the best health of a particular group. However, most commercial breeders find it more cost-effective to house males and females together year-round. This method will save on the space and extra labor required to house and care for numerous males and will prevent missing valuable matings early in a new breeding season.
Careful record keeping on each breeding group regarding egg production, body weight, time of breeding, and health issues, will help maximize the annual production of a colony.
Single Animal Mating Introduction
The single animal introduction method requires the most space and labor, but gives the highest possible production results and is essential when creating new morphs whereby you must know exactly the parentage of specific offspring. With this method, each mature female is introduced to the male of choice for at least 24 hours and then returned to her cage and egg-laying box, this ensures proper tracking of the genes behind those eggs and reduces stress. As a rule, a mating every three weeks will give the best level of fertility. Although a single mating has been known to result in viable eggs for up to a year, the fertility rate is too inconsistent for anyone really serious about breeding leopard geckos.
Although some female reptiles (notably turtles and crocodilians), are capable of reproduction for most of their lives (some reptiles have oogonial stem cells and are capable of oocyte regeneration), many others undergo a menopause where ova are no longer produced. A common cause of menopause in species is starting off with a limited number of oocytes incapable of regeneration, followed by a rate of atresia (degeneration and die off), which often begins before birth. As a result, females literally have a biological clock; only a small number of oocytes will be able to develop into mature ova before they have all died off. We do not know for sure whether limited numbers of oocytes and atresia or other factors are the cause of menopause in leopard geckos but the fact remains that they do indeed undergo menopause, and at a relatively young age considering their potential longevity. Record keeping over the years has shown a female leopard gecko can produce between 80 and 100 eggs over her lifetime. Females who are 2-5 years of age are the most prolific, while you will get fewer eggs from females 5-9 years old. After 9 years of age, the great majority of female leopard geckos enter menopause and egg production falls to near zero. For herpetoculturists, this translates into an effective production of 10-14 eggs per year for the first six years per female. For this reason, all serious commercial breeders will find it essential to replace older females in their colonies with young mature females every 4-5 years. In order to maintain good production efficiency in a colony, 20% of the older females must be removed and replaced by preferably virgin females every year. One of the obvious conclusions is that older leopard geckos over four years old are not good purchase choices for breeding projects.
These non-reproductive females will make good pets and are capable of living perhaps another ten years.
Breeding Part 6 will be presented in the next edition of Tremper’s Corner.