The Insider’s Guide To The Giant Day Gecko

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The Insider’s Guide To The Giant Day Gecko

Phelsuma grandis makes a great pet lizard.

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Thanks to the famous Geico Gecko, the giant day gecko (Phelsuma grandis) is the closest thing to a celebrity lizard that a reptile fan could hope for. You have seen him on television, on billboards and in glossy magazines. Maybe you have even asked yourself, “What makes him so special?” Besides his good looks, you can’t deny that he exudes a certain charm — a swing in his swagger, if you will. It is this je ne sais quoi that inspired mainstream advertisers to launch ambitious campaigns around him. As was the case with the Ninja Turtles before him, when this gecko reached celebrity status, everyone suddenly wanted a piece of him. Now, for the first time, we will expose everything that die-hard day gecko fans have known about this Madagascar native for decades. Here it is, ladies and gentleman: the True Hollywood Gecko Story.


shutterstock/thomas guenther

The Phelsuma Grandis has been called one of the most beautiful lizards in the world.

How He Made His First Million

Although giant day geckos have had a long history in the reptile trade, they have only recently appealed to a wider audience. Their spectacular colors, diurnal behavior and simple husbandry requirements render them perfectly suited for terrarium life. Selectively breeding for color has produced what are arguably the most beautiful lizards in the world: the crimson and blue-blood day geckos. Every season, breeders who specialize in the species produce uniquely colored specimens, thereby enhancing interest among reptile enthusiasts and investors. These designer geckos have accrued a sizable following and demand considerable sums of money. Multiple new projects are currently under way, including the development of the mustard, striped, super-red and super-blue morphs. Expect them to make their debut in the reptile trade in 2013 or 2014.

Before He Was Famous

In the early days of herpetoculture, giant day geckos were virtually unavailable to reptile collectors. This was due to the lack of awareness about the species and the absence of connections to foreign sources to obtain animals. In the early 60s, when reptile books began to publish photos of day geckos, demand started to rise. These books flaunted stunning photographs and commented about how common they were in their native land. Few reptile enthusiasts will forget the first time they saw a photo of a giant day gecko. Likely, their first thoughts were, “How can I get one and are they difficult to keep in terrariums?”

During the mid to late 60s, the first wild-collected specimens from Madagascar showed up in the United States reptile trade. The handful of dealers at the time yearned for shipments from Madagascar because day geckos were in high demand, the resale prices were high, and consequently, profit margins were large.


By the early 70s, some hobbyists were successfully keeping wild-caught day geckos and captive breeding had begun on a small scale. The lines of obtaining animals became established some time between the mid 70s and the early 80s, and reptile dealers then began to carry day geckos on a more regular basis. They sold out as quickly as they could get the geckos in.

During the late 80s through the mid 90s, there was an explosion of wildlife exports from Madagascar. Large numbers of wild-caught day geckos became readily available, and this, of course, brought the price down dramatically. Many of the shipments, each containing thousands of day geckos, reached the United States, Europe and Japan. During this period, it was documented that approximately 240,000 day geckos were exported from Madagascar, which equated to roughly 30,000 individuals annually. Once difficult and expensive to obtain, giant day geckos were now inexpensive and found in virtually every pet shop.

The overseas market demand seemed to be insatiable, and by 1999, due to over-exploitation and dramatically declining natural habitat, Madagascar implemented a program for the management and export of its reptile and amphibian populations. Under this new program, the giant day gecko was listed for commercial export, with annual quotas of 2,000 specimens. With the exception of 2002, when Madagascar imposed a year-long moratorium on the commercial export of all wildlife, this quota has remained.  We are currently reverting to a time when wild-caught giant day geckos will become less available to hobbyists. The good news is that captive-breeding projects occurring outside of Madagascar can supply the demand.

He’ll Never Forget his Roots

The giant day gecko is widely distributed in northern Madagascar, including some of the offshore islets. This is the tropical rain forest region, which is characterized by hot and humid weather. The region is under the influence of the southeastern trade winds, which cause rainfall throughout the year with a slight reduction in the winter. Because there is always high relative humidity and a low level of evaporation, it is often extremely humid. The mean annual precipitation ranges from 35 to 87 inches, and the mean annual temperature is around 79 degrees Fahrenheit. Some areas to the east experience nightly lows in the mid-50 degrees.


Many reptile enthusiasts know Madagascar as a naturalist’s paradise and home to many unique reptiles. Unfortunately, Madagascar is also known as an environmental crisis and ecological emergency. Less than 10 percent of its forests remain, the two greatest causes being extreme poverty and massive deforestation for economic gain. Recently, a governmental power struggle has allowed for further environmental vulnerability, and presently protected reserves are being cut down to supply the international lumber market. Fortunately, field studies have identified that P. grandis is less impacted by deforestation when compared to other reptile species because they are adaptable to multiple environments, including banana plantations and other farm and suburban conditions. Because the giant day gecko has become well-established amongst breeders and collectors, imported animals have become obsolete. Environmentally conscious reptile keepers should insist on purchasing captive-bred specimens only, which are far more colorful and healthy than wild-caught individuals.

A Gecko’s Mansion

Giant day geckos are undemanding terrarium subjects. If provided with a few basic requirements, they will thrive in captivity and reproduce on a regular basis. They lend themselves to a tropically planted, vertically oriented vivarium. Many commercially available terrariums designed specifically for tropical arboreal reptiles exist and are ideal for giant day geckos. An adult pair can be comfortably housed in enclosures measuring 24 inches tall, 18 inches long and 12 inches wide. Other essentials include an ultraviolet light, daily misting, an ambient temperature between 80 to 82 degrees, a basking spot reaching 95 degrees, and a relative humidity of 65 to 85 percent. The terrarium furniture can be simple or elaborate, depending on the keeper’s style and how much time he has to invest on routine maintenance. Bamboo has been a longtime favorite cage furniture and is ideal for climbing, basking, hiding and egg-laying. Light cycles should be 14 hours on and 10 hours off in the summer, and 8 hours on and 16 hours off in the winter. Reducing the temperature in the winter by 5 degrees will condition the geckos for breeding.



His Personal Chef Tells All

Feeding giant day geckos is simple. They eat almost anything that they can overpower and fit down their throats. Their diet in captivity is composed of various insects and pureed fruits mixed with vitamin and mineral supplements. Crickets, mealworms, waxworms, cockroaches, bananas, mangos and peaches are usually accepted without hesitation. If given the opportunity, they will consume small lizards and even pinkie mice. Because their diet is so broad, running to the pet store to buy crickets is not required. They readily accept and thrive on various forms of commercially available powdered diets, but some people prefer to create homemade diets. Visit for a selection of recipes.


In general, a good feeding schedule entails offering crickets one to two times a week and pureed fruit or powdered diets mixed with water and vitamins/minerals two to three times a week. A calcium supplement with vitamin D3 is essential to their development and long-term health. The author prefers to use the ultrafine calcium with vitamin D3 by Rep-Cal. Although some gecko keepers once believed them to be a sign of a healthy animal, chronically enlarged endolymphatic glands (the sacs on either side of the neck) have been proven to be unhealthy and represent over-supplementation and poor metabolism.

His Name Change
Until recently, the giant day gecko was scientifically known as Phelsuma madagascariensis grandis. In 2009, it was elevated from subspecies to full species status, and it now goes by Phelsuma grandis. As its name implies, P. grandis is the largest member of the Phelsuma genus. Reaching a total length of 11 inches, and in some cases 12 inches, these robust, heavy-bodied geckos have a vivid-green color. Most have strong red markings on their backs. The variability in the amount and shape of red markings is limitless. One constant remains: a red stripe runs from the nostril to the eye.

His Love Life and Celebrity Kids

Once they reach sexual maturity at 9 to 12 months of age, males and females are easily distinguished from one another. Males have well-developed femoral pores and hemipenile bulges, whereas females lack these structures.

Compatibility of specimens is essential to facilitate breeding. If a female is not receptive toward the male for breeding, this may cause one of them to attack the other. If this occurs, the pair will have to be separated because constant fighting can lead to severe injury or death of the subordinate animal. Once bonded, a pair or trio can breed for life.

It is best to incubate giant day gecko eggs in a way that maintains high ambient humidity but does not allow the eggs direct contact with water, as this can drown developing fetuses. Incubating eggs on a screen placed above water is an effective way to achieve a constant 90 to 95 percent humidity.

The first hatchling should emerge from its egg 58 to 63 days post oviposition. Usually, the second neonate hatches within 24 to 48 hours after its sibling. A hatchling can stay in the incubator until after its first shed, which occurs two to four days after hatching. After the first shed, the hatchling will consume the same insects as the adults as long as the prey items are sized appropriately. Caging requirements are the same as for adults, only smaller so that the hatchling geckos do not get lost in a large cage and are able to readily find their food.


Touring the Grounds

Giant day geckos will thrive in a vivarium, but they are also well-suited to outdoor enclosures. Day geckos can live outdoors year-round in South Florida and perhaps in select areas in coastal Southern California. If temperatures drop below 55 degrees for extended periods of time, they should be brought inside and provided with supplemental heat. Exposure to natural light, and seasonal temperature and humidity fluctuations, provides many health benefits and is therefore encouraged but not essential.

On the islands of the middle to lower Florida Keys, people have released giant day geckos into their outdoor tropical gardens and have established local populations. The author is the primary investigator in a study identifying the ecological impact this species has had on the area. Please visit for more information.

Blue Blood on the Red Carpet

If you are a day gecko fan, you have probably wondered whether red-and-blue-colored animals are from nature or simply a product of selective breeding. Such high-colored animals are far more common in captivity due to selective breeding, but some do exist in the wild. Biologists studying the giant day gecko in Madagascar have noted animals with splashes of blue and increased amounts of red. Also, very rarely, imported animals have increased red and hints of blue coloration. This appears to be specific to the individual and not related to geographical location.

Some giant day geckos have more of the blue gene than others. In nature, the color blue is very conspicuous. This can be an asset or a liability, depending on the context. Therefore, rather usefully, they have the ability to turn it on or off. If a giant day gecko does not want to be noticed for any reason, its ticket is to stay green and motionless. It is as good as being invisible amongst the foliage. Conversely, giant day geckos go blue when they want to be noticed by other giant day geckos. Blue signals strength, confidence, challenge and bravado. Breeding females also blaze blue to warn other female giant day geckos to stay away. If you are small, green is a better color to be in Madagascar to blend with your surroundings. This is why juvenile giant day geckos rarely show blue color. It should be noted that not all giant day geckos can turn blue — only those that have the blue gene. Moreover, even if they have the blue gene, they rarely turn blue under captive conditions unless they are set up for breeding and housed under optimal conditions. Every year, during breeding season at my outdoor breeding facility in South Florida, the giant day geckos that have the blue gene blaze an amazing blue for four to six months. Some residual blue remains the entire year on certain individuals.

Not a One-Hit Wonder

The giant day gecko has come a long way in herpetoculture. After 50 years of selective breeding, the quality of animals available now far exceeds what can be obtained from the wild. The unique characteristics of this highly sought-after lizard, along with the prospect of some truly unique color morphs in the future, is sure to hold the interest of reptile fans for years to come. Present demand for high-colored specimens greatly exceeds supply, and it is clear that more dedicated breeders are needed to continue to develop this gecko’s possible color varieties.  REPTILES

Jon Klarsfeld, DVM, practices veterinary medicine in South Florida and owns, an outdoor breeding and research facility specializing exclusively in Phelsuma grandis. It is dedicated to the advancement, reproduction, protection and biomedical importance of this species. Dr. Klarsfeld currently consults with a pharmaceutical company to develop a drug of human importance derived from his study of P. grandis. If interested in other topics related to giant day geckos, please read some of Dr. Klarsfeld’s other articles at