The lifespan of these lizards is said to be around thirty years, although in my opinion it’s more like fifty. For females, average adult size is 30in and three and a half to five pounds. For males, average adult size is 36in and five to six pounds. Exceptionally large males can reach 40in and close to ten pounds.

Most Beaded Lizards reach sexual maturity at two and a half to three years old. Once oviposition occurs, the incubation period is around 165 to 215

Beaded Lizard - Heloderma genus

From Wikipedia, the free encyclopedia

Heloderma, the only genus of the family Helodermatidae, consists of venomous lizards native to the southwestern United States, Mexico, and as far south as Guatemala. It includes five separate species, with two subspecies. Their closest living relatives are the anguid lizards.[1]

Helodermatids (or beaded lizards) are large, stocky, slow-moving reptiles that prefer semiarid habitats.[2] Their tails are short and used as fat storage organs. They are covered with small, nonoverlapping, bead-like scales, with osteoderms on the undersides of their bodies. Both species are dark in color, with yellowish or pinkish markings.[3]

Members of the family are venomous.[4] Venom glands are located in their lower jaws, unlike snakes' venom glands, which are located in their upper jaws. Also, unlike snakes, helodermatids lack the musculature to inject venom. The venom is typically used only in defense, rather than in subduing prey, and the lizard must chew on its victim to work the venom into the flesh. Venom glands are believed to have evolved early in the lineage leading to the modern helodermatids, as their presence is indicated even in the 65-million-year-old fossil genus Paraderma.[3][5] Venom production among lizards was long thought to be unique to this genus, but researchers studying venom production have proposed many others also produce some venom, all placed in the clade Toxicofera, which includes all snakes and 13 other families of lizards.[1] However, except for snakes, helodermatids, and possibly varanids, envenomation is not considered medically significant for humans.

Helodermatids are carnivorous, preying on rodents and other small mammals, and eating the eggs of birds and reptiles. They are oviparous, laying large clutches of eggs.[3]

Heloderma
Temporal range: Early Miocene to Recent

Gila monster, Heloderma suspectum

Scientific classification:

Kingdom:Animalia

Phylum:Chordata

Class:Reptilia

Order:Squamata

Superfamily:Varanoidea

(unranked):Monstersauria

Family:Helodermatidae
Gray, 1837

Genus:Heloderma
Wiegmann, 1829

Species:

Heloderma alvarezi
Heloderma charlesbogerti
Heloderma exasperatum
Heloderma horridum
Heloderma suspectum

Taxonomy :

Family Helodermatidae

Genus Heloderma :

H. alvarezi Bogert & Martin del Campo, 1956; Chiapan beaded lizard
H. charlesbogerti Campbell & Vannini, 1988; Guatemalan beaded lizard
H. exasperatum Bogert & Martin Del Campo, 1956; Rio Fuerte beaded lizard
H. horridum (Wiegmann, 1829); Mexican beaded lizard
H. suspectum Cope, 1869; Gila monster

Members of the genus Heloderma have many extinct relatives in the Helodermatidae whose evolutionary history may be traced back to the Cretaceous period, such as Estesia. The genus Heloderma has existed since the Miocene, when H. texana lived, and fragments of osteoderms from the Gila monster have been found in late Pleistocene (8,000-10,000 years ago) deposits near Las Vegas, Nevada. Because the helodermatids have remained relatively

unchanged morphologically, they are occasionally regarded as living fossils.[6] Although the beaded lizard and the Gila monster appear closely related to the monitor lizards (varanids) of Africa, Asia, and Australia, the wide geographical separation and unique features not found in the varanids indicates they are better placed in a separate family.[7]

The type species is Heloderma horridum, which was first described in 1829 by Arend Weigmann. Although he originally assigned it the generic name Trachyderma, he changed it to Heloderma six months later, which means "studded skin", from the Ancient Greek words hêlos (ηλος)—the head of a nail or stud—and derma (δερμα), meaning skin.[8]

In captivity :

H. horridum, H. exasperatum, and H. suspectum are frequently found in captivity and are well represented in zoos throughout much of the world. They are often bred for the exotic pet trade and can command high prices. The other two species of Heloderma are extremely rare, and only a few captive specimens are known.

A Chiapan beaded lizard in captivity.

For the external links , refrences click here to read the full wikipedia article

Video :

Beaded Lizard (Heloderma) scales: osteoderms

Other websites :

- herpetology.com/heloderma.html

- myreptile.ru/forum/index.php?topic=1525.20

- www.helodermahorridum.com/available.php

- animaldiversity.org/accounts/Heloderma/classification/

- www.stlzoo.org/animals/abouttheanimals/reptiles/lizards/mexicanbeadedlizard

- www.iucnredlist.org/details/9864/0

About Beaded Lizard :

The Four Sub-Species of
Heloderma horridum

H.h. exasperatum
H.h. horridum
H.h. alvarezi
H.h. charlesbogerti

courtesy to : www.helodermahorridum.com/beaded_lizard.php

The Mexican Beaded Lizard is one of only two venomous lizards in the world, the other being the Gila Monster (Heloderma suspectum). It’s latin name consists of the two words Heloderma horridum. Heloderma, meaning studed skin, and horridum, meaning horrible (horrible studded lizard). This seems quite a fitting name for this unique animal, although I don't think they're horrible at all. Heloderm lizard's skin consists of several tiny beads called ostioderms. Each bead contains a tiny piece of bone that gives them almost an armor plated skin.

A picture of a Heloderma horridum alvarezi. Photograph credit: Dennis Sheridan

days. At about that time the hatchlings will pip their head out of the egg. It usually takes two or three days for them to come all the way out, absorbing their yolk sack and ingesting the liquid content of their egg. Newly hatched neonates are usually five to six inches and weigh around 40 grams. Until the animals are substantial in size, sexing is nearly impossible. Males generally have much broader heads and longer necks, with females having narrower heads and shorter necks, although there’s always exeptions to every rule.

Types of Beaded Lizards

Class: Reptilia Order: Squamata Family: Helodermatidae
• Heloderma horridum horridum
• Heloderma horridum charlesbogerti
• Heloderma horridum alvarezi
• Heloderma horridum exasperatum
Only the horrdium and exasperatum types are bred in the United States by private individuals. The charlesbogerti type has been bred by the San Diego Zoo.

From top to bottom: An adult, a two year and a yearling

Size Comparison: Male on the left, Female on the right

The animals originate in the Pacific Drainages from Southern Sonora, Mexico to Southwestern Guatemala and two Atlantic drainages, from Central Chiapas, Mexico to Southeastern Guatemala. Habitat is primarily tropicial deciduous forest and thorn scrub forest, also found in pine-oak forest, with elevations from sea level to 1500 meters. In the wild, the animals are only active from April to mid-November. They spend only about an hour per day above the ground, and their natural diet is consistent of reptile and bird eggs and occasionally small mammals. The lizard uses its venom primarily as a defensive weapon. (Johnson, J. P. and C. Ivanyi, 2001. North American Regional Beaded Lizard Studbook. 3rd Edition. Arizona-Sonora Desert Museum.)

H.h. exasperatum habitat - Southern Sonora, Mexico
Photography by C.M. Gienger

A Rio Fuerte beaded lizard in climbing a tree. Photography by C.M. Gienger

The venom glands are located in the lower jaw. At the base of each tooth is a grooved pit for venom delivery. The venom is delivered by the lizard by a chewing motion, a rather crude delivering device. The bite from an animal is extremely painful and can be potentially fatal, but this is only in extremely rare cases. See Bob Applegate's website for an actual bite account.

A pair of Heloderma horridum exasperatums mating.

Heloderma horridum Eggs with hatchlings starting to pip.

To the left: A tooth of a Heloderma horridum, notice the pit in the tooth.
To the right: The Jaw of a Gila Monster (Similar to a Beaded Lizard)
Both drawings come from Bogart and Del Campo's The Gila Monster and Its Allies and were drawn by S.B. McDowell ©1956

Neonate care :

Taking care of neonate Beaded Lizards takes little effort. In my opinion, they’re one of the easiest reptiles to keep in captivity. The lizards should be housed separately in shoebox racks, but can also be kept in an aquarium with heat lamps. A thermostat should be used in all applications. The temperature of their living quarters should ideally be 78° F on the cold end, to 88° F on the hot side. UV lights are unnecessary.

A newyly hatched neonate

Hatching neonates

Proper keeping of neonates

There is no need for vitamin supplements. A bowl big enough to soak their entire body is desireable. Neonates can be started on pinkies for the first two or three meals, but after that you can go straight to hopper mice. I usually feed them about 75% of what they can take once a week.

Beaded Lizard

Mexican Beaded Lizard

Family: Helodermatidae

courtesy to :animal-world.com/encyclo/reptiles/lizards_venomous/BeadedLizard.php

Heloderma horridumPhoto © Animal-World: Courtesy David Brough

The amazing Mexican Beaded Lizards are quite unique among the reptiles!

The Beaded Lizard Heloderma horridum is a spectacle to behold. The size and sheer beauty of this lizard are more than enough to make any intermediate to experienced herp keeper fascinated. Though it is a venomous reptile and its scientific name means "horrible studded lizard", it is a true showpiece.

The Mexican Beaded Lizard is one of two species of venomous lizards in the family Helodermatidae. Both species are similar in appearance and habits, but its cousin, the Gila Monster Heloderma suspectum, is slightly smaller and more colorful.

No other lizards have been have been so immersed in myth and mystery as these two Helodermatidae lizards. Possibly because of their rather secretive lifestyles. They spend a good deal of their time in their burrows and their habitats are very remote.

Other factors that make the Beaded Lizard and the Gila Monster so mysterious could be that they are poisonous lizards, as well as being the sole survivors of an ancient group of lizards, the Monstersauria. They have been two of the least understood and least studied of the lizard species, though they have been regularly kept by herp enthusiasts for several decades.

Mexican Beaded Lizards do not make good "pets". But for a serious herp enthusiast, their habits and environment requirements make them ideally suited for captivity and visual enjoyment. Despite their size, they don't require a lot of area for activity, and they are relatively easy to keep.

CAUTION: These are
VENOMOUS LIZARDS
In many areas, these lizards may only be kept with a license.

The keeping of venomous reptiles is restricted and/or regulated in many localities. Check with your state and city authorities for requirements.

Do exercise caution when handling this lizard. Both species of Heloderma are sluggish in habit, but they have a strong, tenacious bite...with a 'bulldog' attitude of not wanting to readily let go.

The beaded lizards are beautiful animals, and the Mexican Beaded Lizard can be very enjoyable to the experienced herp keeper. They require permits to be owned in many states, and in some states, while the state may not have a law, the city may have regulations regarding these animals.

Scientific NameHeloderma horridum
Subspecies:

Mexican Beaded Lizard Heloderma horridum horridum
Black Beaded Lizard Heloderma horridum alvarezi
Rio Fuerte Beaded Lizard Heloderma horridum exasperatum
Montagua Valley Beaded Lizard Heloderma horridum charlesbogerti

Habitat: Distribution/Background :

The Beaded Lizard Heloderma horridum was first described by Wiegmann in 1829. Mexican Beaded Lizards are found throughout central and western Mexico from latitude 25 southward to northern Central America. They inhabit thorn scrub and pine forests, as well as tropical forest. They spend a vast majority of their time in their dens or burrows.

There are four subspecies of Beaded Lizard, found in the following ranges:

1- Mexican Beaded Lizard Heloderma h. horridum, the nominate Beaded Lizard subspecies, are found in Mexico, from Sonora to Oaxaca.

2- Black Beaded Lizard Heloderma h. alvarezi, described by Bogert and Martin del Campo in 1956, are found in the in the northern Chiapas regions of Mexico to northwestern Guatemala.

3- Rio Fuerte Beaded Lizard Heloderma h. exasperatum, also described by Bogert and Martin del Campo in 1956, are found in Mexico from southern Sonora to northern Sinaloa.

4- Montagua Valley Beaded Lizard Heloderma h. charlesbogerti, described by Campbell and Vannini in 1988, are found in the north-east of Guatemala.

The regions of the first three of these Beaded Lizards overlap and thus they regularly encounter one another while the Montagua Valley Beaded Lizard is isolated from the other three species. Only two if these subspecies, the Mexican Beaded Lizard Heloderma h. horridum and the Rio Fuerte Beaded Lizard Heloderma h. exasperatum are bred in private collections in the United States. The Montagua Valley Beaded Lizard Heloderma h. charlesbogerti has been bred by the San Diego Zoo.

Status :

The Heloderma suspectum is on the IUCN Red List for Endangered Species as Least Concern (LC). The general status of these lizards is relatively staple because three of the subspecies are widely distributed with overlapping ranges, and they are often in protected areas. One subspecies however, the Montagua Valley Beaded Lizard Heloderma h. charlesbogerti, is isolated from the others and in a very limited range. Its population is severely limited, current estimates are only around 200 species in the wild, and it is possibly one of the most highly endangered lizards.

Description :

The Mexican Beaded Lizards, true to their name, have black "beaded" scales with either a yellow or white pattern to them. They have squat, fat tails that store fat reserves. Their forked tongue is serpentine in nature and flicks in and out to smell, much like a snake.

They closely resemble the Gila Monster in many ways, except for being larger and darker colored. The venom glands are in their lower jaws, and the venom leeches out from the glands and flows through the grooves in the teeth of the lower jaw and is delivered by a chewing motion. These lizards use venom primarily as a defensive weapon.
These beautiful lizards can grow to be up to3' (91 cm) in length and weigh around three and a half to five pounds, the females are slightly smaller. The largest males have been known to get to 40" (101 cm) and weigh close to ten pounds. They have a long life span, living 30 to possibly 50 plus years.

Food and FeedingIn :

the wild, the Mexican Beaded Lizard eats mostly the eggs of reptiles and birds, and occasionally small animals. In captivity Mexican Beaded lizards will eat commercially available foods, pinkies, mice, and small rats when they are adults.

While eggs are a natural food source in the wild, these should be avoided in captivity for a few reasons. The salmonella in eggs can be transferred to your lizard. Also, egg foods tends to be fattier. This is only acceptable for lizards in the wild, as they must store food reserves in their tail to make it through when there is no food available. In captivity this can lead to obesity.

Housing :

Adult Mexican Beaded Lizards should be maintained with a minimum of 3 ½ square feet of floor space. Grape vine or other materials may be provided so that they can climb. Substrate can be anything from newspaper to wood shavings, with Aspen shavings being the best. These are easy to clean out and replace and work well with the lizards. Because this is a venomous lizard, be sure that the lizard is kept in an enclosure that has a lid to prevent its escape.

While they are a desert lizard, they need more humidity than most desert animals. They need a large water bowl that they cannot knock over, preferably large enough for them to soak in if they so desire.

Temperature and Lighting requirements:

These lizards like the temperatures in the low seventies on the cool side of their cage to the high eighties on the warm side. A basking area can be as simple as an elevated rock and placed under the basking light. Heating for the basking area can be provided by a clamp lamp and a bulb with wattage appropriate to the size enclosure the lizard is in.

Cage Care :

Cage maintenance is an important part of keeping reptiles healthy, and long-lived. Reptiles being kept in a confined area as pets need to be protected from harmful micro-organisms and parasites. The reptile cage needs daily and weekly maintenance.

Spot cleaning should be performed on a daily basis, or at least following meals. If they are allowed to soak for long periods of time every day in the water bowl, it will need daily cleaning. Any liquid spills should be cleaned up immediately, with the damp litter being removed.

Everything you put into their home should be washed and disinfected weekly. This includes dishes and cage decor. All of the substrate should be replaced every one to two months, depending on the age of the lizard, and how often its feedings are. Never clean with a phenol such as Pine Sol. Chlorine and alcohol based cleaners are tolerated much better, but need to be thoroughly rinsed.

Behavior :

In the wild, Beaded Lizards have a solitary nature. Lizards do not need companionship, and naturally view another lizard as competition for food and territory, and male lizards will compete for females. These lizards can be kept with success in groups, it they are given enough room. But keeping them in solitary enclosures better replicates their natural environment.

Handling :

These lizards should only be handled by trained professionals. A thick pair of leather gloves may be used to offer some protection from these lizards. While many of the adults can be docile, it could take a single person or thing to startle the lizard to incur a bite. These are not tame animals.

NOTE: If you are bitten by a Beaded Lizard, seek medical attention immediately!

ReproductionMost Mexican Beaded Lizards reach sexual maturity at about 2 1/2 to 3 years. Adult males are larger than females and generally have broader heads and longer necks.

In the wild, the male would scent out the female in the late spring. In captivity they have been observed to copulate in May and June. The female then lays her eggs in July and August. The incubation period is about 165 to 215 days, with the eggs hatching the following January to February.

When ready to lay, the female may show some swelling around the rear legs. She should be removed to a private enclose to lay her eggs, as other cage mates will eat them. Provider her with a large nesting box, or put her in an aquarium filled about 3/4 of the way with sphagnum moss for her to burrow down to the bottom of to lay her eggs. She can take up to 24 hours to lay. Vermiculite can be used as an incubation medium, keeping the temperature at about 79{deg} F (26{deg} C).

Neonate care :

in the Mexican Beaded Lizard is quite simple. They should be allowed to exit the egg on their own, even if it takes them a few days to do so. They will not eat for their first few days out of the egg, and up to a week. At a week of age, they should be taking pinkie mice. The temperature range for neonate care is from 78 - 88{deg} F (26 - 31 {deg} C) degrees.

Diseases:

Ailments/TreatmentsThe biggest problem with Mexican Beaded Lizards is obesity, due to their extremely low metabolism. Take good care to only feed as much as is necessary.

Availability:

Mexican Beaded Lizards can be purchased from specialty breeders via the internet.

Note: Before attempting to find a breeder or other source for your Mexican Beaded Lizard, you need to check the laws of both your state and your city for the regulations in your area.

References