Species and subspecies:
Giant horned lizard, Phrynosoma asio Cope, 1864
Short-tailed horned lizard, Phrynosoma braconnieri Duméril, 1870
Cedros Island horned lizard, Phrynosoma cerroense Stejneger, 1893
Texas horned lizard, Phrynosoma cornutum (Harlan, 1825)
Coast horned lizard, Phrynosoma coronatum :
Ditmars' horned lizard or rock horned lizard, Phrynosoma ditmarsi Stejneger, 1906
Pygmy short-horned lizard, Phrynosoma douglasii
Greater short-horned lizard, Phrynosoma hernandesi Girard, 1858
Flat-tail horned lizard, Phrynosoma mcallii (Hallowell, 1852)
Roundtail horned lizard, Phrynosoma modestum Girard, 1852
Mexican Plateau horned lizard or Chihuahua Desert horned lizard, Phrynosoma orbiculare
Desert horned lizard, Phrynosoma platyrhinos
Regal horned lizard, Phrynosoma solare Gray, 1845
Mexican horned lizard, Phrynosoma taurus Dugès, 1873
Gulf Coast horned lizard, Phrynosoma wigginsi Montanucci, 2004
1- The giant horned lizard (Phrynosoma asio) :
The giant horned lizard (Phrynosoma asio) is a species of phrynosomatid lizard which is endemic to the Pacific coast of southern Mexico. It is the largest horned lizard and is also the most slender (it has a typical lizard-like appearance). Like all lizards, the giant horned lizard is cold-blooded. It is able to survive in the desert. The spines on its back and sides are made from modified scales, whereas the horns on its head are true horns (i.e., they have a bony core).
Giant horned lizard
Conservation status :
Least Concern (IUCN 3.1)
Scientific classification :
Binomial name :
Jump up^ The Reptile Database. www.reptile-database.org.
巨型角蜥飼育 - Phrynosoma asio Feeding
Care Articles :
1- Giant Horned Lizard
courtesy to : www.reptiletalk.net/giant-horned-lizard/
Phrynosoma asio is a large, hardy species of Horned Lizard (HL) that does well in captivity. These are very sociable Horned Lizards, interacting to each other with head bobs, arm waves, and tail wags.
Phrynosoma asio lack the sleek, tubular body shape of most lizards. Instead, they have a wide, flattened form which is well adapted for camouflage and their burrowing habits. Horned lizards are noticeably spiny, with a crown of horns adorning the back of their heads and various spines on their bodies.
Scientific name : Phrynosoma asio
Distribution : Southeast Mexico, Guatemala
Average Size : 0.16 m (0.5 ft)
Life Span : 10 years or more
Difficulty : Intermediate
Image Credit : Strophurus DE
The most advisable terrarium to use when housing a Phrynosoma is glass which provides medium-high ventilation. This allows us to maintain both a good temperature and good ventilation. A terrarium made of PVC can also glass would be the preferred choice considering its properties. The terrarium should be longer and wider than it is tall, 1.5 x 0.6 x 0.4 meters (5 x 2 x 1.3 feet) for example. As the Phrynosoma is an active animal it is advisable to use a large tank in order for them to move freely, as well as making sure that the terrarium contains a cool area amongst its hotter zone in order for the animal to be able to go through thermoregulation.
Hide box :
Phrynosoma tend not to hide in very deep shelters, they usually rest on branches, or make a small bed between rocks and sand, so a cave or shelter is not necessary as used for Australian geckos and leopard geckos.
The substrate should consist of a mixture of fine sand and earth, with a layer of about 0.05 meters (0.16 feet). It is also important to place various sized rocks and branches in the terrarium in order for the animal to be able to seek refuge and climb.
Lighting – Heating :
It is important to maintain the Phrynosoma in an environment close to its natural one, so therefore the lighting must be intense and of high quality similar to their own habitat. We recommend using HID (metal halide) bulbs, which provide a high amount of UVB and a substantial temperature. A flat stone or rock should be placed under the hot spot in order for the animal to be heated well.
A minimum of 8-10 hours a day of light is needed between the months of January-April which then needs to increase to 12-14 hours a day between May-October. The temperature of the hot spot should be approximately 45-50 °C (113-123 °F) making sure that the ambient temperature of the terrarium is always kept at a minimum of 18-25 °C (65-77 °F). If you are able to expose the Phrynosoma to natural sunlight, with the confidence that they cannot escape, and have shaded areas, it is a good opportunity to do so as the natural sunlight is extremely beneficial for both their organism and metabolism.
Phrynosoma will gain much of the water they need from their food, but as we have pointed out earlier it is desirable to spray them twice a week in summer, and a couple of times per month in the winter to obtain the required amount of water needed. As in almost all reptiles, it is advisable to give access to the animal a shallow bowl with clean fresh water daily.
Between the months of May to October it is important to frequently spraying the terrarium a minimum of twice a week. You should hit 60-70% humidity and between spraying let the enclosure to get almost dry. With this way you are replicating the raining season. We can also spray the skin of animal as they are able to absorb the moisture through their skin and they can also drink this excess moisture when water is poured onto them. Between the months of October to April it is only necessary to spray the terrarium once or twice a month.
We must pay special attention when it comes to food as these animals feed on ants in their natural habitat making up 30% of their diet. In captivity it is not necessary to provide ants, since there are now several commercial products made specifically to supplement the lack of formic acid. Whilst giving substitutes of formic acid, we can include ants as well as other insects in their diet safely which are available in most reptile stores. It is advisable to add a variety to the diet so that the Phrynosoma get used to all kinds of insects, such as crickets and cockroaches, even worms honey and locusts.
It is important to add in addition to live feed various fruits, pollen, spirulina and anything that can bring more nutrients to the Phrynosoma’s diet. Phrynosoma will feed on the daily maximum allowance when there is variation. It is important to provide supplements twice a week with a mixture of calcium and minerals, and if possible once every 15 days with a specific formic acid supplement.
As in most reptiles, these animals do not like to be handled at all times but they can handled occasionally. The Phrynosoma is not an aggressive animal with humans so they can be handled well as long as done so with care for the animal.
Terrarium cleaning must take place once or twice per week, as these animals are quite voracious therefore generate a large amount of excrement, which must be removed frequently. Excrement can easily be removed with a strainer and the sand will remain clean. It is recommended to change the substrate approximately every 4 months if using this method of cleaning.
In the case of shedding, like almost all desert reptiles, the process will last between 2 and 3 days. The substrate and the internal decoration of the terrarium will help the shedding process of the animal as they can use this to pulverize the outer layers, whereas the humidity will help soften the skin.
Potential Health Problems :
No specific potential health problems to mention for this species beyond those affecting reptiles in general. They seem to be a relatively hardy animal when kept properly.
2- First North American Captive Breeding of the Giant Horned Lizard
courtesy to : blogs.thatpetplace.com/
Horned Lizards of various species, usually sold as “Horned Toads”, were US pet trade staples in the 1950’s and 60’s. Looking much like minute dinosaurs, they needed more heat and UVB than most could provide, along with an ant-dominated diet, and fared poorly. As a boy, I was able to keep them going in the summer, thanks to natural sunlight and plentiful ants, but they declined in winter (I discovered they did not like the “house ants” I collected in local stores!). As I moved into zoo work, the key to keeping most species remained elusive. So I was very happy to hear that the Los Angeles Zoo had recently (January, 2011) succeeded in breeding the largest species, the Giant Horned Lizard, Phrynosoma asio.
Natural History :
The 6 ¼-inch-long Giant Horned Lizard inhabits tropical scrub, rocky hillsides and forest edges along the Pacific Coast of southern Mexico. Unlike the more familiar desert-adapted species, it experiences prolonged rainy and dry seasons, and seems less dependent upon an ant-based diet.
The Giant Horned Lizard is one of the eight species in the genus Phrynosoma known to squirt blood from its eyes when disturbed (please see photo).
Captive Breeding :
Partly because they accept food other than ants, Giant Horned Lizards have done rather well, and have even bred, in European collections. The 9 eggs that hatched at the LA Zoo represent the first North American success. The parents are part of a group imported from Mexico and shared with the San Diego Zoo.
European reports indicate that Giant Horned Lizards mate in April-June, with gravid females laying 10-30 eggs after a gestation period of 60-70 days. The eggs hatch in 10-12 weeks when incubated at 85 F.
Horned Lizard Care :
Horned Lizards are hard to resist, but it is a mistake to attempt keeping them unless you are well-experienced and able to provide for their very specific needs.
Those that accept a variety of insects, such as the Short-Horned Lizard, Phrynosoma douglassii, are better choices than the ant specialists. The Short-Horned Lizard, I learned to my surprise and delight many years ago, also gives birth to live young.
Please write in for details on proper care before acquiring a Horned Lizard.
Lizard Oddities :
As if their appearance, diet, and blood-squirting abilities were not enough to distinguish Horned Lizards, several species are now known to guard their nests, attacking snakes and other predators…others inflate themselves with air and flip over as if dead when attacked (please see video below).
And there’s more – both the Giant Horned Lizard and the Coast Horned Lizard, Phrynosoma coronatum, have been observed mating in a most un-reptilian manner…belly-to-belly!
Other websites :
3- Phrynosoma Asio Husbandry
courtesy to : bion.com.ua
by Jeff Judd
This is a large, hardy species of Horned Lizard (HL) that does well in captivity. It has a good appetite and thrives on a varied diet. These are very sociable Horned Lizards, interacting to each other with head bobs, arm waves, and tail wags. They are aware of their surroundings, and can recognize humans as a food source; they will watch in anticipation as food is being offered, and will eat from your hand.
GHLs should be housed in a glass terrarium. Overall, it should be long and wide but not very tall. Shallow tanks allow good ventilation and prevent heat from building up. The top of the substrate to the top of the terrarium should measure around 12 inches. The substrate level can be raised to accommodate a taller tank. The length and width needed depends on the number of GHLs that will be housed. However, the bare minimum for one or two adults should be 36" long x 18" wide.
Benefits of Large Tank: :
No terrarium is too large. Generally, the bigger the terrarium is, the better. With adequate space, intense lighting can be provided them, as well as a wider range of temperatures for GHLs to properly maintain their preferred body temps. GHLs will be able to properly feed, and exhibit more natural behaviors. Also, you can create a more realistic landscape that will better resemble their natural environment.
What to add: :
The bottom of the terrarium should be covered with three to six inches of sand. The sand should consist of various sized particles. Giant Horned Lizards purposely ingest specific sizes of these particles to aid in digestion. Rocks large enough for the GHLs to bask on should be placed under the heat lamp to provide basking sites. The cool side of the terrarium should contain plants or branches to provide areas for climbing. Suitable plants include many spineless cactus, succulents, palms, grasses, and non-toxic houseplants. Giant HLs are semi-arboreal, and during periods of inactivity, they will climb onto the plants or dead branches, or seek shelter under half-cut tree bark, cactus hollows, or sturdy rock formations.
The 160-watt or 250-watt mercury vapor heat lamps specifically designed for reptiles work very well for GHLs. They provide adequate levels of UV radiation as well as produce heat, which are both essential to keep GHLs healthy long term. Fluorescent lighting can be added if additional light is desired. The lights should be turned on and off by a 24 hour timer. They should be set to come on 13 hours a day May, June, July and August, 11 hours a day March, April, September and October, and then 10 hours a day November, December, January and February.
The terrarium should be placed in a room that stays between 65 and 75 º F year round. The heat lamp should be placed at one end of the terrarium while the other end remains unheated. The height of the lamp should be adjusted so that directly beneath the bulb the temperature is around 115 º F after the bulb has been on for an hour. This will provide a range of temperatures allowing the HLs to maintain their preferred temperature. No additional heating devices are needed after the lamp turns off, so the night temperatures should be falling between 65 and 75 º F.
Diet and Nutrition:
Giant Horned Lizards should be fed daily. They should be fed in the morning, or the late afternoon when they are most active. If they are fed in the morning, they should be allowed to warm up for about an hour beforehand. The insects should be placed in the same area of the terrarium at each feeding, because the Giant Horned Lizards will recognize a feeding area and look for food there. An individual’s appetite depends on its size, the time of year, and stress level. Generally, it is best to continue to feed the HL until it has no more interest in food.
In captivity, ants, crickets, or roaches should make up most of the diet with the occasional mealworms and waxworms. All of these insects are available commercially. Make sure the insects are from a clean source, otherwise they can harbor disease, which can be passed onto the GHLs. Crickets, roaches, and mealworms should be fed baby cereal and carrots before they are fed to the GHLs. The size of the insects is the most important aspect of feeding; they should be no longer than the width of the GHLs head. Feeding your Horned Lizards large insects can cause them to regurgitate it the next day, become very sick, or die.
Ants (Pogonomyrmrex barbatus and Pogonomyrmrex rugosus) should be included daily. The ants available commercially from the genus pogonomyrmrex are eagerly accepted by GHLs. They should be kept in a large jar with a lid that has very small holes drilled into it. It's important to only put 3-5 ants in the tank at a time. Dumping large numbers in will cause the GHLs to panic, often resulting in the ants biting or stinging them. Immediately remove any GHLs, then the ants if this happens. If an ant latches on with its pinchers, it must be removed by crushing its head with tweezers then slowly pulling it off. Offer ants until the HL stops eating or showing interest. Remove any that are not eaten with forceps or large tweezers.
Crickets (Acheta domestica) and roaches (Nauphoeta cinerea) can be offered every other day. They come in many sizes, and do well with both hatchling and adult GHLs. They can easily be gut loaded and coated with vitamin and mineral supplements. However, crickets can be difficult to catch unless their hind legs are removed. Mealworms can be offered once or twice a week. They are difficult to digest. The number offered needs to be closely monitored. No more than 3 or 4 should be offered at one feeding. The freshly shed mealworms are best. These are white in coloring, and should be fed to Giant Horned Lizars when they are available. Waxworms are large and high in fat, which may be harder to digest in large numbers. No more than one or two should be offered to adults, once a week.
Giant Horned Lizards should receive a good reptile vitamin supplement and a good reptile mineral supplement twice a week. They are sold separately, so they must be mixed together. Add equal amounts of both in a jar, then put enough of either the crickets or roaches in for one feeding. You should shake the jar until the insects are coated with the supplements, then feed them to your Horned Lizards.
Water & Humidity:
May through October it rains very frequently in areas inhabited by GHLs. During this time, the whole terrarium should be misted twice a week with a hand sprayer. The substrate should be dampened, but not too wet and should dry out between waterings. The humidity should be kept between forty and seventy percent. Thoroughly mist the head and nostril area of the GHL until you notice that it is drinking water during each misting. November-April the terrarium should be kept dry. If live plants are used in the setup they can be watered by lightly misting the substrate around their base. The humidity should stay below 40 percent. Water should only be given to the Giant Horned Lizards once a month during this time.
If outside temperatures are in the range of the above Climate Graph, GHLs can be placed outdoors. Behavior and health of certain individuals seems to improve when they are exposed to natural sunshine. The outdoor enclosure should be constructed of wood, screen, or fiberglass. All outdoor enclosures should be completely covered to prevent escape, as well as protect the GHLs from predation.
When placed in screen enclosures, nervous individuals should be watched closely. It doesn’t take long for one to rub its nose raw. Make sure the GHLs always have access to shade. Shade can be provided placing plants in the enclosure or by covering part of the top with wood. In some areas, small ants are a big problem. In a matter of an hour, thousands of small ants can mob and kill Giant Horned Lizards. In these areas, outdoor time should be brief and closely supervised.
GHLs mate from May to June. If successful, the female will lay eggs sometime in July or August, 60-70 days after copulation. She will become very restless and walk back and forth across the terrarium looking for a nesting sight. After a few days, she will usually choose a moist area near the heat lamp to dig a shallow pit 1 to 2 inches deep then deposit from 10-28 eggs. They must be retrieved shortly after they are laid, or they will spoil from the heat lamp. Turning the heat lamp off will extend the time the eggs can remain in the substrate. The female will be emaciated after the eggs are laid, and she will require plenty of food and water.
Carefully remove substrate over the nesting site with a spoon, or your fingers until the eggs are unearthed. Use the spoon to transfer the eggs one at a time to a plastic container with a lid using 1 to 2 inches moistened perlite or vermiculite as the incubating medium. The lid should have 6 to 8 small holes drilled in it to allow air exchange. The medium should be moist but not soggy. This is about 4 parts of the medium to 3 parts water by weight. Too wet of a medium will spoil the eggs.
Place the container in an incubator set with the constant temperature between 82-86ºF. The eggs will hatch 11-12 weeks after they were laid. Water should not be added during the incubation periodunless the medium becomes dry to the touch and the eggs collapse farbefore they are due to hatch. Eggs ready to hatch will also collapse,so testing the medium is crucial. Usually a few eggs from a largeclutch will spoil during the incubation period. These eggs shrivel andare attacked by mold. The hatchlings usually emerge within 2 days afterthe eggs start to collapse. Do not remove hatchlings half-way out ofthe egg. They will stay in this position for a long period of time toabsorb the yolk and also to adjust to breathing. Removing them tooearly will often result in the death of the hatchling.
Giant Horned Lizard hatchlings should be raised the same as adults, with only a few modifications. They should be set up in groups of no more than four so that their food intake can easily be monitored. If raising large numbers of hatchlings, the glass terrariums can be substituted with plastic containers about 36 inches long by 18 inches wide by 12 inches tall. The hatchlings should be fed twice every day.
Food & Water:
The main foods of P. asio hatchlings should consist of ants, very small crickets and roaches, and occasionally small freshly shed mealworms. Remember that ants can sometimes intimidate hatchlings. If the ants are not eaten right away, they should be removed. Putting the ants in the refrigerator for five to ten minutes will slow them down,making them easier for the hatchlings to take down. You should be giving the hatchlings water and vitamin and mineral supplements every other day.
Species and subspecies:
Species and subspecies: