Gila monster characteristics, habitat, reproduction, feeding

1888
Charles McCarthy

The Gila monster (Heloderma suspectum) is a poisonous lizard that belongs to the Helodermatidae family. It is a reptile that is characterized by the color of its body and because it is covered in scales..

The area of ​​the face and legs are dark, while in the dorsal region it has patterns of lines and bands of brown or black color. These stand out against an orange, pink or yellow background. The striking body designs tend to vary as the animal ages.

Gila monster. Source: SearchNet Media [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)]

Another relevant aspect is that it has venom-producing glands, located on both sides of the lower jaw. In addition, their teeth have special adaptations for the inoculation of this toxic substance.

This species is native to the Mexican state of Sonora and the southeastern region of the United States. As for its habitat, it lives on rocky slopes, in low deciduous forests and at the bottom of canyons, where there are sources of water..

Article index

  • 1 Features
    • 1.1 -Size
    • 1.2 -Thermoregulation
    • 1.3 -Coloring
    • 1.4 -Head
    • 1.5 -Poison
  • 2 Taxonomy
  • 3 Habitat and distribution
    • 3.1 Climates
    • 3.2 Types of vegetation
  • 4 Danger of extinction
    • 4.1 Threats
    • 4.2 Current situation
    • 4.3 Actions
  • 5 Playback
    • 5.1 Courtship
    • 5.2 Mating
  • 6 Food
    • 6.1 Large intakes
  • 7 Treatment for type II diabetes
  • 8 References

Characteristics

Jeff Servoss [Public domain]

The body of this lizard is robust. Their limbs are short, with large fingers and strong claws. These, together with its strong muscles, allow it to dig for its prey and climb trees and shrubs..

As for the tail, it is thick and short. This constitutes a store of fat, which is used as an energy source in the event of a shortage of food or during hibernation..

This structure measures about a quarter of the total length of the body. Generally, its end is pointed, but in some species it may be thick and rounded.

In the Heloderma suspectum, the difference between males and females is not very noticeable. However, the male has a wider head and a more oval body than the female..

-Size

The Gila monster can measure between 26 and 36 centimeters, not counting the tail. Their body mass ranges from 350 to 700 grams. However, some large species could reach 56 centimeters in length and weigh up to 2300 grams..

-Thermoregulation

It is an ectothermic reptile, with an ideal body temperature of 29 to 30 ° C. It has organic and behavioral adaptations that allow it to live in arid habitats.

When environmental conditions cause your body temperature to rise to 37 ° C, the body responds by dramatically increasing water loss through the skin's surface..

Another option to lower your body temperature by up to 2 ° C is the high evaporation of water produced by the sewer. In addition, this reptile spends 90% of its time under stones or in sand caves, to protect itself from extreme heat..

During the summer, every 4 or 5 days the Heloderma suspectum changes den, always looking for a cooler micro habitat that contributes to its thermal regulation.

-Coloration

The reptile's body is covered in scales. In the dorsal area these are shaped like round ossicles, similar to protuberances. In contrast, those in the ventral region are flat and rectangular in shape..

The coloration of the scales located in the region of the face and on the legs are dark. Generally, in the young, the back has double crossed bands, black or brown, that simulate a chain. These stand out against a background that can be yellow or pink or orange.

This pattern is usually maintained until adulthood, when it becomes more complex. As for the tail, it is characterized by having the same colors, but arranged in the form of alternate rings.

The speckled design could serve as camouflage among desert vegetation, but the bright coloration works as an aposematic warning to potential attackers..

The females begin their molting process before laying the eggs. The change of skin begins in the area of ​​the cloaca, then the stomach and the scales of the inner part of the tail.

-Head

Jeff Servoss [Public domain]

The head of the Heloderma suspectum it is large and robust. It has a flat snout and a black tongue, which is divided at the tip. This muscle is flexible and attached to the hyoid bone..

As for the eyes, the pupil is rounded and the eyelids are mobile. This species has a nictitating membrane, which slides from the lateral nasal angle, moisturizing and protecting the cornea.

The ear is externally protected by a membrane. In relation to the Jacobson's organ, it is located in the upper jaw. When the reptile moves its tongue, with the tip it captures the olfactory stimuli, which reach the brain through the vomeronasal organ, to be interpreted.

This species has strong jaws that, together with the powerful adductor muscle, can hold and bite the prey. You could also use them to crush the head of small mammals, such as mice..

Teeth

All teeth have a slightly backward curved point and a flattened base, which is embedded in the jaw. In addition, they have channels located longitudinally, through which the poison passes.

The Heloderma suspectum change teeth throughout life. When replaced, the base is absorbed and the spare tooth is positioned where it belongs. This process occurs in such a way that the jaw and the tooth are always attached.

-Poison

Poison glands are located on both sides of the lower jaw. Due to the fact that this reptile lacks the muscles that allow it to inject the venom, this substance reaches the tooth while it is chewing. Then, by capillary action, it leaves the tooth and reaches the victim.

A typical behavior of the Gila monster when it bites its attacker is to vigorously shake its head. This could be related to the intention of facilitating the release of the poison.

Specialists point out that this toxic substance is used as a defensive weapon and not to subdue its prey. Thus, the intense pain that it produces in the victim causes them to give up their attack. In the case that it bites the human being, it does not bring fatal consequences.

Taxonomy

Animal Kingdom.

Subkingdom: Bilateria.

Phylum: chordate.

Subfilum: Vertebrate.

Superclass: Tetrapoda.

Class: Reptilia.

Order: Squamata.

Suborder: Autarchoglossa.

Family: Helodermatidae.

Genus: Heloderma.

Species: Heloderma suspectum.

Subspecies:

- Heloderma suspectum suspectum.

- Heloderma suspectum cinctum.

Habitat and distribution

Scott Sandars from Melbourne, Australia [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]

The Gila monster is distributed in the southwestern United States and northwestern Mexico. Thus, it can be located from the southwestern region of Utah, California, Nevada, New Mexico and Sonora to the northern region of Sinaloa, in Mexico..

Generally lives in areas where there are rocky slopes, avoiding open regions with plains. Among the preferred areas are the rocky basalt lava, where it can be easily camouflaged and where it could find a refuge that allows it to escape from predators..

As for the lair, the H. suspectum it uses unoccupied burrows, which could be reused at different times of the year. The refuge could be one meter deep and its length is usually approximately two meters.

Also, this species lives at the bottom of canyons, in which there are semi-permanent or permanent streams. Other ecosystems where it usually inhabits include pine oak forests, thorn forests and low deciduous forests.

Climates

The Gila monster inhabits a great diversity of desert climates, ranging from very arid-warm, with average annual temperatures above 22 ° C, to semi-arid-temperate climates in which temperatures are between 12 and 18 ° C.

Vegetation types

The vegetation includes desert grasslands and scrublands, typical of Sonora and Mohave, in Arizona. In Mexico, it inhabits plains, low mountain slopes, and beaches, while in New Mexico it is associated with desert scrub vegetation. It could occasionally be found in oak and juniper forests.

As for the southern part of Arizona, it is abundant in the palo verde-saguaro desert, as it is rocky and humid. To a lesser extent, it occupies the creosote desert, because it is sandy and dry..

Danger of extinction

Gila monster populations have decreased, which is why the IUCN has categorized it as a species that is close to being vulnerable to extinction.

Threats

This species has been illegally exploited by people who sell them in the market, mainly due to the attractiveness of its coloration. However, the main cause of population decline is habitat destruction.

Man has cut down forests to build urban development and agricultural developments. This has drastically modified environmental conditions, which has repercussions both on the development of this reptile and on the increase in risks that endanger its survival as a species..

Such is the case with roads. These, in addition to fragmenting the ecosystem, constitute a barrier to the movement of the Gila monster. The mortality of this animal increases as vehicular traffic increases, since they die in the attempt to travel on said road.

Current situation

Currently, the panorama in each of the regions where it lives has its own peculiarities. Thus, in most of the subtropical scrub and oak forests where it lives, the environment is partially preserved. However, streams are polluted and livestock is degrading the soil.

In the municipality of Mezquital, in Durango-Mexico, the main problem is extensive livestock farming, poaching and the replacement of the area's vegetation with introduced pastures, among which is the buffel grass (Cenchrus ciliaris L.).

One of the best conserved areas is the desert, where scrub is abundant, sarcocaule and crasicaule. However, they are at risk from firewood extraction, overgrazing, poaching and hunting activities..

In coastal regions, the main problem is the transformation of the land into tourist and agricultural areas.

Actions

The Heloderma suspectum It is part of the animals included in Appendix II of CITES, where are the species that could be strongly threatened with extinction if their trade is not controlled.

In addition, hunting this species is prohibited by regulations and laws in all the states of Mexico and the United States where it lives..

Reproduction

In the male, the testes are round in shape and located above the kidneys. Spermaducts are ejection channels that pass through the edge of the kidneys. These join with the ureters shortly before emptying into the cloaca. In this way they form a joint outlet.

In relation to the hemipenis, they are found in leather bags located on both sides of the base of the tail. At the beginning of the mating season, males shed the skin covering their hemipenis.

Courtship

One of the behaviors typical of males before mating is combat. During it, the dominant male rests on the subordinate, holding him with his limbs. They both arch their bodies, pushing each other and twisting, striving to gain dominance.

The winner will be favored by the females to reproduce. Courtship begins when the male makes close movements towards the female and brushes her with his tongue. Then he begins to rub his chin against the female's back, while slowly walking around her..

As time passes, the actions become more insistent, putting more pressure on the head and neck. If the female does not flee, the male positions the front part of her body on the back, hugging her to facilitate contact between her cloaca.

Mating

During copulation, the male stands next to the female and slides the base of his tail under the female, thus introducing one of the hemipenis. The sperm is transferred to the cloaca of the female. Fertilization occurs when mature eggs pass through the oviducts, towards the cloaca.

After two months of gestation, the female lays between 1 and 12 eggs in the burrow. At the end of the incubation stage, the hatchling, which is still inside the egg, has a developed tooth, known as an egg tooth. This allows you to break the shell from the inside, in order to get out.

Feeding

The Heloderma suspectum it is a carnivorous animal, whose diet is made up of reptile and bird eggs, small rodents, young rabbits, squirrels and chicks, which they capture in their nests. They also eat lizards, insects, and carrion.

This species detects prey mainly using its highly developed sense of smell. For this it uses its tongue, which captures the chemical stimuli and transmits them to the Jacobson's organ. Thus, it is able to locate and unearth eggs that are buried 15 centimeters away.

In addition, it can capture the vibrations of the ground, thus being able to find nests and young that are in burrows. To gain access to that underground area, it uses its claws and limbs, which due to its strength make it easy for it to dig efficiently.

Large intakes

The Gila monster possesses the ability to consume a large amount of food at one time. Thus, young people could eat up to 50% of their weight in a meal, while adults eat the equivalent of 35% of their body mass.

This offers great advantages to the reptile, especially considering that in its environment it could become difficult to find prey with some regularity. In addition, the accumulated fat reserves in its tail allow it to fast for a long time.

In this way, three or four large meals provide you with enough energy to keep your vital functions active until next spring. Likewise, its low metabolic rate reduces its need to eat food regularly..

Treatment for type II diabetes

The researchers found in the saliva of the Gila monster a substance known as exendin-4, which participates in the digestion of nutrients and in the regeneration of the gastric tissues of the animal.

However, the most relevant contribution consists of the similarity of this compound with the digestive hormone GLP-1, responsible for the homeostatic balance of glucose in humans. Another important aspect is that exendin-4 remains in the body for a long time, and can last up to 12 hours..

Before this discovery, various attempts to replace the hormone produced in the human intestine had failed, because the compound disintegrated very quickly..

Another advantage of exenatide is that its use reduces the frequency of hypoglycemia, since its function is associated with blood sugar levels. In addition, it helps in the regulation of the glucagon hormone, generated by the pancreas.

This is why exendin-4 offers an efficient molecular model to counteract the metabolic disorders caused by type II diabetes. Thus, drugs based on this active principle can be easily generated in pharmaceutical laboratories..

References

  1. Jim Rorabaugh, Roger Repp (2019). Gila Monster (Heloderma suspectum). Tucson Herpetological Society. Recovered from tucsonherpsociety.org.
  2. Stewart, M. 2003. Heloderma suspectum. Animal Diversity. Recovered from animaldivresity.org.
  3. Wikipedia (2019). Gila monster. Recovered from en.wikipedia.org.
  4. Hammerson, G.A., Frost, D.R., Gadsden, H. (2007). Heloderma suspectum. The IUCN Red List of Threatened Species 2007. Recovered from iucnredlist.org.
  5. Kevin Bonine, (2005) Heloderma suspectum. Digital Morphology. Recovered from digimorph.org.
  6. George R. Zug (2019). Gila monster. Encyclopaedia britannica. Recovered from britannica.com
  7. Alina Bradford (2017). Facts About Gila Monsters. Lives cience. Recovered from livescience.com.
  8. CONABIO (2019). Gila lizard. Heloderma suspectum. Recovered from encyclovida.mx.
  9. ITIS (2019), Heloderma suspectum. Recovered from itis.gov.
  10. Hans-Joachim Schwandt (2006) Gila Monster (Heloderma suspectum). Recovered from heloderma.net.

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