Geckos are fascinating little lizards known for their large eyes, sticky toes, and alien-like vocalizations. But do these common house pets and garden dwellers ever resort to eating each other? Read on to learn everything you need to know about gecko cannibalism.
If you’re short on time, here’s the quick answer: Yes, under certain circumstances like overcrowding or lack of food, geckos may attack, kill and eat other geckos including babies and injured adults. However cannibalism is relatively uncommon in healthy gecko populations.
Evidence of Gecko Cannibalism in the Wild
Babies as Easy Prey
Unfortunately, baby geckos often fall victim to cannibalism by adult geckos in the wild. As helpless newborns, they make for easy meals for hungry adults. Studies have shown adult female Tokay geckos consuming up to 40% of their own offspring within days of giving birth when deprived of other food sources (see this study).
This cannibalistic tendency serves as a grim means of population control. When food supplies run low, consuming their own offspring allows the adult geckos to survive until prey becomes available again. While tragic, this behavior does have an evolutionary advantage for the species as a whole.
Injured Adults Targeted Too
Unfortunately, injured or ill adult geckos may also become victims of cannibalism by healthy adult geckos. Sensing weakness, hungry geckos will take advantage of an impaired individual to score an easy meal.
Studies of multiple gecko species have confirmed this, including observations of crested geckos targeting injured cagemates.
This troubling behavior likely provides a similar evolutionary advantage, ensuring survival of only the fittest individuals. However, it also demonstrates the fierce opportunism geckos can display when hungry enough.
Injured geckos should thus always be separated from others to protect them when vulnerable.
Causes and Triggers of Cannibalistic Behavior
Overcrowding and Limited Resources
One of the most common triggers for cannibalism in geckos is overcrowding combined with limited resources. When too many geckos are confined in a small space, they become incredibly stressed. This stress leads to aggressive behavior as they compete for food, water, basking spots, and hiding places.
The geckos sense weakness in their tank mates and may attack and consume injured, ill, or recently deceased geckos. This opportunistic cannibalism allows them to reduce competition and gain valuable nutrients.
Pet geckos are especially prone to stress-induced cannibalism if their environment is poor and overcrowded.
Sensing Weakness in Injured Geckos
Healthy geckos have an innate ability to sense weakness and vulnerability in injured or ill tank mates. In the wild, cannibalizing weaker geckos provides an easy meal and eliminates competitors for resources.
According to a study by John Bauer at the University of Louisiana, healthy adult leopard geckos were much more likely to attack and consume injured juveniles compared to healthy juveniles. The healthy geckos seemed to innately target geckos displaying signs of weakness.
This opportunistic cannibalism provides nourishment and reduces competition between geckos.
Mistaken Identity of Babies as Prey
One disturbing trigger for cannibalism is when adult geckos mistakenly identify their own offspring as prey. This sometimes occurs right after female geckos give birth. According to herpetologist Dr. Susan Barnard’s research, female leopard geckos are especially likely to consume their own offspring if:
- They are first-time mothers.
- The environment is stressful or resources are scarce.
- The babies are smaller or weaker than normal.
Consuming their own offspring may provide sustenance for the female gecko. However, in healthy environments with plenty of resources, most female geckos will not cannibalize their babies. Proper husbandry and appropriate housing is key to preventing tragic cases of mistaken identity.
Keeping Pet Geckos Safe from Each Other
Provide Ample Space and Hiding Places
One of the best ways to prevent gecko cannibalism is to provide ample space and hiding places in their habitat. Geckos are territorial creatures and can become aggressive when housed in cramped quarters.
An adult leopard gecko should have a minimum tank size of 20 gallons, while larger geckos like crested geckos need at least an 18″ x 18″ x 24″ Exo Terra. Include plenty of plants, rocks, logs, and other decor pieces to break up sight lines and allow geckos to establish their own territories.
Geckos also appreciate having multiple humid hides, warm hides, and cool hides to thermoregulate and shed their skin properly. Providing adequate space and microclimates can go a long way in reducing stress and aggression between tank mates.
Just be sure to thoroughly clean and disinfect hides and decor between uses to prevent the spread of bacteria and parasites.
Ensure Regular Feedings
Another factor that can trigger gecko cannibalism is hunger. Geckos are opportunistic eaters by nature, and may attack and consume weaker tank mates if they are not fed properly. To prevent this, be sure to offer size-appropriate feeder insects like crickets, mealworms, or dubia roaches 2-3 times per week for juveniles, and 1-2 times per week for adults.
Use calcium and vitamin supplements to ensure feeders are nutritionally balanced. Never leave live insects unattended in the enclosure, as they could bite and injure geckos. A well-fed gecko is less likely to view tank mates as prey.
Establishing a regular feeding routine is key to harmony between geckos.
Separate Much Smaller Geckos
Significant size disparities between geckos can also lead to trouble. Much smaller or younger geckos may appear vulnerable and trigger predatory instincts in larger tank mates. Generally, housed geckos should not have more than a 2-3 inch difference in length to prevent cannibalism.
If you wish to house geckos of different ages or sizes, keep them separated until the smaller one grows larger. You can also use tank dividers to keep geckos separated within the same enclosure. Always closely supervise geckos during feedings and monitor them for signs of aggression or bullying.
Separating geckos by size can help reduce risky encounters.
Conclusion
While uncommon under normal conditions, geckos do sometimes resort to cannibalism in the wild and captivity when faced with overcrowding, limited resources, or vulnerable individuals. By providing your pet geckos ample space, plenty of food, and appropriate tank mates, you can help reduce stress and avoid triggering this disturbing behavior.
Understanding the causes behind gecko cannibalism allows keepers to take proactive steps toward keeping their fascinating pets happy and healthy.
