Iguana de mona: Mona Rhinoceros Iguana – International Iguana Foundation

Mona Island Ground Iguana | Encyclopedia.com

Cyclura stejnegeri

Status	Threatened
Listed	February 3, 1978
Family	Iguanidae (Lizard)
Description	Large iguana with a series of rings set close together in the tail and a ridge of flexible, spinelike organs running down the back; the head is covered, at least in part, with larger scales or tubercles; the dorsum is patternless and dark gray, grayish-brown, or black.
Habitat	Maritime climates where the humidity levels are high and temperatures are mild and fairly stable.
Food	Fruit, flower buds, and new green leaves.
Reproduction	Clutch of five to 19 eggs hatched early in the fall.
Threats	Hunting, habitat loss, predation by exotics, and pet trade.
Range	Puerto Rico

Description

Cyclura stejnegeri is a large iguana (snout-to-vent length, or SVL, in males to 18.2 in [46.3 cm], in females to 20 in [51.0 cm]), also known by the name Mona Island ground iguana. Its dorsum is patternless and dark gray, grayish-brown, or black. Juveniles are very dark and virtually patternless but have about nine pale crossbars on their sides, separated by dark gray areas (often series of gray blotches) extending onto the undersurface of the abdomen; hind limbs are not ocellate. Female Mona Island ground iguanas are strikingly similar to males in outward appearance. They have equivalently well-developed cephalic horns, a mid-dorsal crest, and a dewlap (throat fan). Older females also have large bodies and enlarged, sagging jowl musculature.

Behavior

C. stejnegeri suns primarily in the morning and late afternoon, basking on exposed lookouts. These iguanas are usually very shy, retreating into the den when disturbed, but they can become more tame when exposed daily to human intrusion. They will
enter the water as an escape tactic. Males select territories with retreats attractive to females; females select retreats according to location and structure. Preferred retreats have good drainage, ventilation, a nearly horizontal resting place under a low ceiling, and are within 5 ft (1.5 m) of the surface.

Challenges over mating territory are resolved through fights between males, which are highly formalized tests of strength. These face-to-face pushing matches, performed with mouths wide open, usually last less than 15 minutes and end without violence when one or both contenders back away slowly in retreat. At times, however, battles are longer, lasting up to an hour, and involve biting and tail lashing.

The Mona Island ground iguana eats fruits (especially Opuntia [Cactaceae]), Hippomane mancinella (Euphorbiaceae) leaves, flowers, and some animal matter (especially Pseudosphinx tetrio caterpillars and pupae). Feeding is not a daily requirement; about 95% of the normal daily routine is rest, with or without basking. The species prefers plants that are low in cellulose, low in aromatic compounds, and easy to obtain. The diet of juveniles is like that of adults except for size of items eaten. A large proportion of Mona Island’s native trees and shrubs bear fruit under 0.6 in (1.5 cm) in diameter, which the iguanas prefer over leaves. When readily available, fruits are invariably taken to the near exclusion of leaves. In spite of their seasonal occurrence, fruits are the principal plant foods contributing to growth, reproduction, and fat reserves. However, these iguanas will consume mice in captivity.

Mating occurs annually during a two-week period. Males lie in wait for the female located in his territory 6-10 ft (1.8-3 m) from her retreat, with his eyes fixed on the burrow entrance. When she appears, he displays a series of toss-roll head movements, dashes to her with his head lowered, pauses briefly by her side for another series of head movements, and then grabs her tail or loose flank skin to restrain her. Unwilling females may turn and bite or, more commonly, struggle into a crevice, dislodging the male. Females store sperm, and eggs are presumably fathered by more than one male since she may copulate with several males. Eggs are deposited about one month after mating and are warmed by direct sunlight in a tunnel about 3 ft (0.9 m) long. Clutch size is five to 19 soft-shelled eggs. Nests may be guarded by the female, as she returns to the nest one to ten days after depositing the eggs to inspect the site and stand guard against intruders (including other females searching for nest sites). Defense against persistent intruders includes head rolling, broadside challenge, huffing, biting, tail lashing, and delivering sand back into the rival’s hole and on the rival. The length of the iguana nesting season on Mona Island is short. The island’s climatic regime appears to determine how late in the year an iguana can nest successfully. Hatching normally occurs about three months after laying, in October and early November, the two wettest months of the year, providing optimal conditions for juvenile emergence, feeding, and dispersal before the abrupt onset of the annual dry season in January.

Habitat

The terrain of Mona Island is marked by sharply weathered limestone, intense heat and glare, and aromas of sea, frangipani blossoms, and pungent shubbery. The island is actually a vast, bean-shaped slab of sedimentary rock situated midway between Puerto Rico and the Dominican Republic. Almost 95% of Mona’s 13,600-acre (5,503.7-hectare) area is a relatively homogeneous, slightly domed, and undulating tableland, limited around the windward, northern perimeter by sheer cliffs that drop some 150-280 ft (45. 7-85.3 m) to the sea. The cliffs of the south side are steep but break away in many places as talus slopes that descend to a narrow coastal terrace 10-12 ft (3-3.5 m) in elevation. Rainfall averages 32 in (81 cm) annually, but because of its highly permeable limestone substrate and general lack of soil, Mona has no watershed and only supports a slow-growing forest of xerophytic shrubs and trees. Surface depressions in the rock, a few of which exceed 3 ft (0.9 m) in diameter, catch and hold rainwater for periods ranging from hours to, occasionally, months. Water also collects seasonally behind rimstone dams and in some of the caves. The scarce accumulations of soil on the plateau are confined to small, shallow potholes and sparse sinkhole depressions. The coastal terrace is mantled with a thin, spotty layer of sandy soil.

Distribution

The iguana population on Mona Island, approximately 1,500-2,000, is currently smaller than the habitat could support but appears to be reasonably stable. Although predation on some nesting sites by
pigs is currently controlled by fencing, suitable nesting areas appear limited.

Threats

Threats to this taxon include feral pigs that prey on eggs, and feral cats, significant predators on hatchlings. Goats are keeping favored food plants from reproducing. Although hunters do not appear to be a serious threat, they do lobby for keeping large feral pig and goat populations on Mona for easy sport hunting.

Conservation and Recovery

The Chelonia-Herpetological Society of the Universidad Metropolitana, in cooperation with the Puerto Rico Department of Natural Resources, has begun a small-scale nest site restoration project. At present, captive husbandry should be secondary to protection/restoration of wild habitats. More intensive wildlife management, especially implementation of a cat control program, is needed. Mona Island has been declared critical habitat for the Mona Island ground iguana, the hawksbill turtle, the Mona boa, and the yellow-shouldered blackbird, all of which are on the U. S. Fish and Wildlife Service list of threatened and endangered species.

Contacts

Boquerón Ecological Services Field Office
Boquerón, Puerto Rico 00622-0491
Telephone: (787) 851-7297
Fax: (787) 851-7440

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
(404) 679-4000
http://southeast.fws.gov/

References

U. S. Fish and Wildlife Service. 1984. “Mona Iguana Recovery Plan.” U. S. Fish and Wildlife Service, Atlanta.

Wiewandt, T. A. 1973. “Mona Amphibians, Reptiles, and Mammals.” In Mona and Monita Island: An Assessment of Their Natural and Historical Resources. Environmental Quality Board, Office of the Governor of Puerto Rico, San Juan.

Mona ground iguana – Facts, Diet, Habitat & Pictures on Animalia.bio

Mona ground iguana – Facts, Diet, Habitat & Pictures on Animalia.bio

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Mona ground iguana

Mona ground iguana

SPECIES

Cyclura cornuta stejnegeri

The Mona ground iguana (Cyclura stejnegeri ) is a rock iguana that is endemic to Mona Island, Puerto Rico, and is the largest native terrestrial lizard in Puerto Rico. It was previously considered a subspecies of the rhinoceros iguana (Cyclura cornuta ).

This is a part of the Wikipedia article used under the Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA).

Appearance

The Mona ground iguana is a large-bodied, heavy-headed lizard with strong legs and a vertically flattened tail, which is capable of reaching 1.22 m (4 ft 0 in) in length (from snout to tail). A crest of pointed, horned scales extends from the nape of the neck to the tip of the tail. The color is a uniform gray to olive drab, with slight brown or blue colorations. Juveniles differ from adults in that they have gray transverse bands across their bodies. These bands last until they are sexually mature at about three years of age.

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Males possess bony, prominent tubercles on their snouts resembling horns, adipose pads in the form of a helmet on the occipital region of their heads, and large dewlaps. This subspecies, like other species of Cyclura, is sexually dimorphic; males are larger than females, and have more prominent dorsal crests, “horns” and femoral pores on their thighs, which are used to release pheromones. Thomas Wiewandt, who spent an extended period on Mona Island studying C. stejnegeri, suggested that the horns, along with lateral spines and prominent parietal bulges, function as protective armor against sharp rocks or as defensive tools to facilitate the escape of males from the grasp of one another.

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Mona ground iguana

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Distribution

Geography

Mona ground iguanas are diurnal and spend most of the day basking in the sun conserving energy. Mona ground iguanas are endemic to Mona Island; they are scattered through the entire island, though the southwest part of the island is only used during the nesting season. They live a considerable portion of their lives underground, and are usually found in talus slopes, caves and sinkhole depressions. The average depth underground that they can be found is 1.5 m (4 ft 11 in).

Habits and Lifestyle

Diet and Nutrition

Mona ground iguanas, like most Cyclura species, are primarily herbivorous, consuming leaves, flowers, berries, and fruits from different plant species. A study in 2000 by Dr Allison Alberts of the San Diego Zoo revealed that seeds passing through the digestive tracts of Cycluras germinate more rapidly than those that do not. These seeds in the fruits consumed by Cyclura have an adaptive advantage, by sprouting before the end of very short rainy seasons. The Mona ground iguana is also an important means of distributing these seeds to new areas (particularly since females migrate to nesting sites) and, as the largest native herbivores of their ecosystems, they are essential for maintaining the balance between climate and vegetation. Their diets are very rarely supplemented with insect larvae, crabs, slugs, dead birds, and fungi; individual animals do appear to be opportunistic carnivores. Fewer than a dozen animal species and 71 plant species are found in the Mona ground iguanas’ diets. Mona ground iguanas eat the caterpillar of sphingid moths. These larvae feed on poisonous plants and are aposematically colored and avoided by other predators.

Diet

Herbivore

Mating Habits

Although Mona ground iguanas use the whole island as their habitat, only 1% of the territory, located on the southwest coast, is suitable for nesting because it contains loose sand, and receives direct sunlight. The females bury their eggs in the sand, and the sunlight incubates the eggs. Males reach sexual maturity at a size of 28–31 cm (11–12 in) in length from snout to vent, usually in their third to fourth year, while females mature one year later at a size of 35–40 cm (14–16 in).

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Nesting season begins in the second week of June. Usually, one female mates with more than one male in the two weeks the mating season lasts. Copulation may last from 15 sec to 2 mins and 15 sec. One month later, nesting begins. Females will dig a tunnel 0.91 m (3 ft) long located one to two feet underground, where they deposit from five to 19 eggs, with 12 being the average. They will guard their nests for several days, but provide no parental care for the hatchlings, which hatch three months later. Hatchlings measure, on average, 32 cm (13 in) and weigh 73.7 g (2.60 oz) and grow at a rate of 5.23 cm (2.06 in) per year.

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Population

Population number

Population numbers are estimated at 1,500 with lower densities than similar iguana-inhabited islands in the West Indies. Immature iguanas are scarce and represent only 5–10% of the population, revealing that the population is aging and in decline.

References

1. Mona ground iguana Wikipedia article – https://en.wikipedia.org/wiki/Mona_ground_iguana

2. Mona ground iguana on The IUCN Red List site – https://www. iucnredlist.org/species/29605/2790768

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