Rhinoceros Iguana ( Cyclura cornuta ). Also called horned iguana, it is a species of iguana linked to the habitats of the Caribbean islands. There are two subspecies in danger of extinction due to human pressure on the insular environments that this reptile occupies . Perhaps it is the most aggressive of the iguanas; It attacks even the man, especially when it comes to stealing his eggs.
Summary
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- 1 Taxonomic Classification
- 2 Description
- 3 Sex Differences
- 4 He lives
- 5 Distribution
- 6 Intraspecific variation
- 7 Iguanas in their natural environment
- 1 Power
- 2 Behavior
- 3 Playback
- 4 Conservation
- 8 Rhinoceros Iguana in captivity
- 1Longevidad
- 2 Diet and food
- 3 Recintos
- 4 Playback
- 5 Incubation
- 6 Births and care of young
- 9 sexado
- 10Madurez sexual
- 11 Clinic
- 12 Fountains
Taxonomic Classification
- Animalia Kingdom.
- Phillum: Chordata.
- Subphylum: Vertebrates.
- Class: Reptilia Linnaeus, 1758.
- Subclass: Diapsida Obsborn, 1903.
- Infraclase: Lepidosauria.
- Orden: Squamata Oppel, 1811.
- Suborder: Sauria Macartney, 1802 (= Larcertilia Owens, 1842).
- Infraorden: Iguania Cuvier, 1817.
- Family: Iguanidae Gray, 1827.
- Genus: Cyclura.
- Species: Cyclura cornuta cornuta.
- Common name: Rhinoceros iguana.
Description
The Rhinoceros Iguana is characterized by conical scales (small horns) on the upper part of the snout, the back of its body has spine-like scales that extend from the neck to the tail. It owes its name to the three horns that the males exhibit on the upper part of the snout. It has a brown coloration with olive green or blue variations on the lower part, tail and legs; the latter end in fingers with fine claws. They can reach a length between 50.8 to 127.5 cm long.
sex differences
As in many species, the male is the one who reaches the greatest size and weight. They weigh between 12 to 25 pounds.
Habitat
This reptile lives mainly in coastal and arid areas of dry and thorny forests and its main population is found in the southern region of the Dominican Republic .
Distribution
The Rhinoceros Iguana is found only in Puerto Rico , the Dominican Republic, and Haiti .
intraspecific variation
This species is separated into two subspecies:
- Spanishrhinoceros iguana Cyclura cornuta cornet.
- Distribution: Hispaniola
- Talla:
- Macho de 560mm SVL y 10kg
- Hembras 510mm SVL y 5.4kg
- Status: IUCN Red List – Vulnerable, Common and dispersed up to the 50’s, its number has been declining until the 1950’s, its number has been steadily declining in Haiti and some portions of the Dominican Republic. On Hispaniola there may be 20 or more sub-populations.
- Estatus Legal: U.S. Endangered Species Act – No en Lista.
- I.T.E.S. – Appendix I
- Priority Activities: assess the situation of wild populations and investigate the factors that limit their numbers. Control and eradicate exotic competitors and predators.
- Remaining number: Estimated between 10,000-17,000 individuals (a few hundred additional in captive collections worldwide).
- Iguana de la Isla Mona Cyclura cornuta stejnegeri
- Distribution: Puerto Rico.
- Talla:
- Machos de 535mm LHC (media 517mm) y 6.4kg (media 6.1kg)
- Hembras 490mm LHC (media 475mm) y 5.2kg (media 4.7kg)
- Status: IUCN Red List – Endangered. This subspecies has been reproducing successively but the mortality of the offspring is extremely high.
- Legal Status: US Endangered Species Act – Threatened (listed as C. stejnegeri)
- I.T.E.S. – Appendix I
- Priority Activities: Laws are enforced for your protection. The Puerto Rican government has recently restricted visits to the island. If a program to eliminate exotic predators and competing herbivores in succession is resumed, there is hope that it will survive. Expand and maintain fencing program to protect nesting areas. Access to the status and habitat of wild populations in order to develop a conservation strategy for the species. Determine the causes of blindness that is affecting many adult iguanas.
- Remaining number: 1,500-2,000 individuals.
Iguanas in their natural environment
Feeding
Rhinoceros iguanas eat fruits , leaves , and flowers in their habitat . Although they are mainly herbivorous animals, they also eat (especially juveniles), insects , small invertebrates and eggs .
Behaviour
Like most Iguanas, Rhinoceros Iguanas have good eyesight and smell and their eyesight is also excellent. They are primarily a ground lizard, but they occasionally climb trees to reach fruit and rest. Like other reptiles , these Iguanas must bask in the sun , to warm up before becoming active during the day.
Reproduction
The Iguanas reach their sexual maturity, between five to nine years. The breeding season lasts around two weeks in April and is apparently triggered by the onset of the rainy season. The female lays between five and twenty eggs in a burrow around 40 days after copulating. The eggs have an incubation period between 90 to 100 days. Juvenile Iguanas are about seven inches long and have a very active demeanor.
conservation
Unfortunately, the genus Cyclura includes some of the fastest disappearing lizard species and critically endangered reptile species on earth . Historically these iguanas have always been restricted to the islands of the Bahamas , the Greater Antilles , and the Virgin Islands , although their historical distribution was certainly much greater than today. On many islands where they still occur, they are the largest native land vertebrates.
Indeed, iguanas are not known natural predators. Their decline in numbers began in pre-Columbian times when the Arawak and Lucayan Indians sought them out as food to supplement their diet with protein. Hunting pressure by these native people may have started the process of decline in rock iguana numbers , but the real devastation began with the arrival of Europeans on the islands. It was not only the extensive devastation of habitat, if not also the introduction of domestic animals, many of them turned feral. Today the greatest threat to iguanas is probably direct predation and competition with these introduced animals. The list is extensive, with cattle , pigs , goats , rats , mongooses , dogs or cats present on many inhabited islands throughout the Antilles .
Rhinoceros Iguana in captivity
The data about the captivity of the rhinoceros iguana has been taken from more than 20 years of experience with the species at the Cyclura Research Center (CRC).
Longevity
Historically, Cyclura iguanas have been poorly represented in zoological institutions. Longevity in zoos around the world before 1987 was less than 2.5 years, apparently the private sector keeps them a little better, ranging between 15 and 25 years in captivity. There are records of animals that have been captive for more than 30 years. Many of these old animals show little evidence of their advanced age and indeed appear to be reproductively active.
Diet and feeding
We believe that the successive breeding with these iguanas at the Cycluras Research Center (CRC) is due to some factors. The first thing is the provision of a balanced diet of high quality, green leafy vegetables that are rich in positive calcium . He is also fed the following mix daily consisting of about 70% leafy greens, 15% mixed vegetables, 10% fruits and flowers, and less than 55% animal products. The young are fed daily with the above mixture, and the adults are fed two or three times a week.
Green Leafy Vegetables: Cabbage , Collard Greens , Mustard Greens , Parsley , Turnip Greens , Escarole , and Green Dandelions .
Legumes: Legumes ( alfalfa , soybeans , etc.), Beans ( lima , kidney , cord , etc.) Mixed Vegetables: Squash , grated ( banana , summer , zucchini , etc.), Corn , Broccoli , Cauliflower , Asparagus , Brussels Sprouts and Buds . Fruits and flowers: Melon , apples , pears , bananas ,plums , figs (very high in calcium), and grapes . Hibiscus Flowers , and Amargón Flowers . Optional (less than 5% of diet for juveniles and gravid females, 2% for adults): Low-fat, low-protein dry dog food (senior premium or less active) soak in water first to soften (Science Diet, Iams, Pro-Plan, Nutro, etc.), diet for primates. Supplements: Multi-vitamins (Reptivite, Herptivite, etc.) Calcium and mineral supplement ( Rep-Cal , Miner-all , Neo-Calglucon, etc.) Water: Fresh drinking water available at all times every day. Cut thinly for juveniles or more abundantly for adults. It is not necessary to feed a wide variety of inputs, just vary the food offerings each week.
enclosures
Two basic designs have been used in the CRC. Originally wire mesh enclosures are built on a concrete wall and heated by a thermostatically controlled heater. Individual cages within the frame are lined with Formica and have large access doors for easy cleaning of the interior. There are openings in the wall to allow access to the cages that serve as sunbeds for the iguanas. Controlled by lockable doors where animals can be controlled, both inside and outside the cages while cleaning or maintenance or when temperatures are low.
The outer portion of the enclosure is started by digging a 6” wide by 18” deep trench, within which is backfilled with concrete. A wooden structure is built that is attached to either of the two ends. A 60” (1.5 meter) square section at one corner of the outer cage is dropped and soil is removed to a depth of about 16” (.4 meter). This hole is filled with sand providing a nesting area for the iguanas. The rest of the enclosure is planted with grass and decorated with piles of rocks and small palm trees. This hole is filled with sand and maintained as a nesting area for iguanas.
The second design is now used in all new built enclosures. This consists of a 2” x 8” square PVC-coated hardwood base that is stapled together with wire mesh and individual sheets that are overlapped and secured to each other. This wire mesh cover prohibits any iguana from digging out of the exhibit. The entire base is then shed on top, put in place on a level area, and then filled with sand or broken down granite. A 2”x 4” wood frame is built and braced onto this base and covered with galvanized welded wire.
Finally a 24” wide strip of 5/8” thick exterior match adhesion is added along the sides of the enclosure to prevent nervous animals from charging at the wire or rubbing their noses on it. The cages are normally at least 6 feet tall so that they can be comfortably serviced by a medium tall adult.
Reproduction
Copulations can occur several times throughout the year in captivity, especially when the iguanas are first introduced. Breeding normally takes place for a few weeks each year during May and June . Successive copulations have been observed on many occasions. Preceded by head bobs by the male, who makes circles behind the female doing it by the nape. Trying to hold her and get her tail under hers and bring her into her own position for the intrusion of one of the emipenes .
Copulations generally do not last more than 30 to 90 seconds (rarely longer) and it is rare for a couple to mate more than once a day. The CRC’s Cycura nubila is the first species to lay eggs, starting in the first week of June , while C. corneta usually does so a little later, nesting in August . All eggs laid in early OctoberThey have always been infertile. Gravid females begin the nesting process with reduced food intake and increased activity levels two weeks before laying. The abdomen is enlarged, the sexually mature adult female distending it to the point that the outer line of the eggs can be easily observed. A few days before the wave sets they dig all over the cage, making many shallow depressions. In cages with substrate sand, a triangular piece of playwood is placed in one corner.
Females begin to dig suitable nests under playwood, usually taking an entire afternoon to dig a complete nest. Females often remain underground for more than two days while laying eggs, but usually emerge in the morning and make a mound over the hole where the eggs were laid. Eggs are collected immediately after laying begins and artificially incubated indoors, but many females continue to guard the nest site for several weeks. If the mound of sand is flattened after the eggs are collected, the female will move large amounts of sand to try and cover the area. This behavior normally lasts for a week or two, but can be induced in some individuals for months.
Incubation
After collecting the eggs they are placed inside plastic containers, with five cm. depth of vermiculite. This dry substrate could first be mixed with 1 and ¼ parts water with one part (1.25:1) incubation medium (measured by weight, NOT by volume). The eggs are placed inside the substrate with the other half exposed to the air space inside the container. Care must be taken not to move the eggs and to keep them in the same position in which they were laid.
The eggs inside each container are marked and placed inside an incubator at 30 ºC. The containers are opened for a period of 30 seconds every three days to allow air exchange. Fertile eggs are usually full, swollen, and white in color. They are often distinguishable from infertile ones, which are often but not always soft, floppy, and slightly yellow. Eggs that are held by a female for a long time before she begins to lay are hard and misshapen. All eggs laid are hatched but those that appear to be infertile are separated from the “good” ones and usually collapse and mold very quickly and are discarded.
Births and care of the young
During incubation, the fertile eggs increase substantially in size, at 30ºC (85ºF), the young begin to hatch as early as possible at 80 days, denting slightly a few days before the first cut appears. After they successively cut the shell of the egg with their small egg tooth, the hatchlings will usually remain with only their heads out of the egg, for more than two days. During this time it will be important not to disturb them. If we startle them they can get out of the egg before all the material (yolk) is absorbed into their abdominal cavity. Since they are released from the egg, they can be in the container for two or three days until the navel closes.
The movement of the first to hatch in the nest over the others probably stimulates the others to hatch in unison. This is necessary in free life as they ensure that they can dig to the surface, a process that requires a group effort. At incubation temperature all healthy hatchlings are usually out by 90 days. For this period of time it is not necessary to add additional moisture to the substrate, but if incubation exceeds this time or if the eggs show evidence of dehydration, more water can be added if necessary. Water can be added to the substrate between the eggs but never spread directly on the eggs. Even a few degrees of temperature reduction would result in a prolonged incubation of 120 to 140 days, with a higher percentage of unhatched eggs.
Although in CRC there have been no twin births, this incident has been documented in other institutions of twins from the same egg. Normally all hatchlings in each box or container are expected to be out of their eggs for two to three days before removing them from the incubator.
Four to five hatchlings are placed inside a large 30-gallon terrarium, with clean paper as substrate. A heated platform is placed under the terrarium at the end of it. Two lights are placed: a 60w blue or red bulb, or a ceramic bulb that emits heat, used to heat the terrarium. The other is a fluorescent with full spectrum UVB radiation. Both lights can be controlled 24 hours a day with timers and thermostats. The fluorescent light can be controlled automatically for periods of 12 hours. By this method the night temperature can be maintained between 21 and 27ºC (70 to 80ºCF), raising it to 32-35ºC (90-95ºF) during the day. A shelter box (optional) can be placed at the end of the terrarium, and a shallow container for water.
Iguana hatchlings molt almost immediately, in thin layers as their skin dries for the first time. Their bellies are distended with yolk, they often do not start eating after 10 days. Also around 7 to 10 days they shed again; in large sections. No differences in growth or survival have been seen between fed offspring of adult iguanas and ones that are not. Sufficient microflora for its own digestion is probably obtained from the crickets and larvae that are sometimes (but not always) fed to the young in the first weeks of life. In fact, in 1999 a season of hatchlings were not fed insects and all hatchlings developed normally.
Interestingly, C. nubila seemed to really like crickets and larvae, while C. cornuta only ate a little sparingly. The pups were kept indoors for the entire first winter, and were moved to an indoor/outdoor enclosure when temperatures began to warm in spring. Growth was rapid, over 20 inches in total length within the first year.
sexed up
The most reliable method of sexing Cyclura is by gavage. It is not recommended in young iguanas of two or three years of age, because the membranes of the cloaca are very delicate. It can be tested by pricking directly into the membranes and under the skin of the tail even with light pressure.
At three months the females have a depth in the probe of 5 mm., while the males are close to 12 mm. deep. By two to four years of age, secondary sexual characters are becoming apparent, and the presence of the male’s reproductive organs, the emipenes, can be visually detected at the ventral base of the tail. Adult female C. cornuta will have a probe close to 15 mm. deep while adult males 50 or more deep. Sexually mature males (of many species ) will also have femoral pores enlarged and arranged in one or two rows on the lower thighs.
sexual maturity
The growth rate in captivity is higher compared to wild iguanas. This is due to the rich diet they receive, on a continual basis. Consequently, sexual maturity is extended at a young age compared to their wild relatives.
In breeding and reproduction in captivity, females of C. nubila have obtained eggs at an early age (21 months), although it is more common at three years. C. cornuta also breed successively at three years or, more commonly, at four years.
Clinic
The Cycluras have very few medical problems , kept or raised in outdoor enclosures, sometimes they are infested with parasites that are controlled in check-ups with the use of Pyrethrin at 03%, or with synthetic sprays of the same product (used in birds ). The spray is left on the iguana for two or three minutes and then rinsed off completely.
Ivermictin prescription is also used as an injection and topical spray for the control of ectoparasites in reptiles . Taking care that the spray does not reach the eyes, mouth and nose. A second treatment is applied two weeks after the first. Iguana enclosures can be treated with the same spray allowing it to remain on the surface for 10 minutes before cleaning.
Wild Cyclura harbor huge swarms of pinworms in their intestines. Because these endoparasites are associated with health problems in captive animals, it is necessary to carry out a routine 1 or 2 times a year with Panacur 10% paste or granules ( Fenbendazole ). Although otherwise healthy animals are not usually negatively affected, heavy infestations can greatly affect an animal if it is ill or under stress.
Some wounds between males and females have required suturing during violent courtship processes. Minor cuts and scrapes, usually self-made, often heal by applying antibiotic sprays or topical ointments to the affected area, reducing the risk of infection. The CRC has suffered few losses of adult Cycluras in the last 20 years.
Salmonella and Arizona are sometimes found in fecal analysis on both captive and wild Cycluras. These are considered to be part of the intestinal microflora but can become pathogenic when animals are under high stress. These organisms can be transmitted to humans and other animals and sometimes cause serious health problems and rarely death.
