Marine Iguana

Marine Iguana

It is unique in its way of life, being the only true marine lizard. The stories of the oldest visitors Galapagos testify on his repulsive appearance. A tale describes it as characterized by the appearance more horrifying imaginable, and the author, a British Royal Navy captain, reports that, "because of this its disgusting appearance, no one on board was able to use them as food." Marine iguanas grow up to 1.2 m in length. They have a blunt snout, heavy body, legs awkward-looking, with long fingers and a ridge that runs from neck to tail. The tail, laterally flattened, is used for swimming. Most of marine iguanas is black or very dark gray, but the Isle of Hood, in the southern part of the Galapagos archipelago, their body is variegated with black, orange and red, and the front legs and the crest They are green.

Biology

Behavior

Outside the breeding season, when they are not committed to feed at sea, marine iguanas gather in tight groups, sometimes even on top of each other. Lie on the lava fields, which are a predominant feature, but not pleasant, Galapagos. During the hottest hours of the day, seeking shelter under rocks, in crevices or in the shade of rizoforee. At the beginning of the breeding season, the males surround the small territories, so small that an iguana can be on top of a rock, while another lies at the foot of the rock. Occasionally, they light up the fighting, but disputes are generally resolved with performances. Male iguana threatens an intruder surging on strong legs and swinging his head holding his mouth open, to show a red mucosa. If this does not cause the intruder to desist, the owner of the land comes forward and takes place a fight. The two opposing pushing with their bony heads, until one of them does not give in and retires.

While marine iguanas enjoy the sun, big red crabs pass and pass over them, stopping occasionally plucking and pulling the skin. Iguanas do not they take it to this, and with good reason, because the crabs do nothing but remove ticks from their skin. The Darwin's finches are doing their utmost even in the same service.

Supply

When the tide goes down, the marine iguanas are worn in the water and eat the algae remained uncovered on the beach and on the cliffs. Clinging to the rocks with their sharp claws, so as not to be swept away by the undertow. Then eat on the rocks tearing the filaments of algae, keeping them firmly around his mouth and surging to take them on. Every so often, they stop to rest and swallow. Some marine iguanas swim offshore over the surf and dive for food on the sea floor. There are reports of iguanas that have cibate a depth of 10.5 m, but usually stop to about 4.5 m. Each dip is prolonged for about 15-20 minutes, but they are able to remain immersed for much longer. When Darwin, aboard the Beagle, visited the Galapagos, he noticed that a sailor trying to drown an iguana soaking it with a heavy weight. But, pulled back to the surface an hour later, it was realized that he was still alive.

Marine iguanas, normally, do not eat that seaweed. Exceptions are unusual marine iguanas dwelling in the house of Carl Angermeyer. He had trained to rush to his whistle and let feed with raw goat meat, rice and oatmeal.

Reproduction

When males have determined their territories, females join them. They are free to move from one territory to another, but the males gather a harem quickly around them and mating takes place without the interference of other males. Courtship is simple: a male following a female, shaking his head, then grabs her by the neck and surrounds with their feet.

When the males leave their territories, females gather on the beaches of nesting. There is competition for nesting sites and sometimes light up the fighting. Each female digs, with all four feet, a gallery of 60 cm in the sand. Sometimes it trapped and killed when the roof collapses or when a nearby well to dig too short.

It is laid only two or three eggs, white, with dimensions of approximately 8 x 4.5. Subsequently, the female iguana fills and camouflages the gallery. When the eggs hatch after about 110 days, iguanas emerge about 23 cm long.

In addition to humans, the main enemies of adult marine iguanas are the sharks; but the iguanas usually take place near the shore, where the sharks generally do not go. Young iguanas are captured by herons, gulls and Galapagos hawks and even cats.

Thermoregulation

During his stay in the Galapagos, Darwin realized that the marine iguanas do not let themselves push into the sea. In fact, they preferred to be captured rather than advancing in the sea. And, if you throw in the water, they reached the shore clinging precipitously wherever they were allowed. Such conduct is at least surprising for an aquatic animal, since most of the animals that habitually swim, such as seals and turtles, if threatened, seek salvation in the sea. Darwin proposed that the marine iguana was acting so weird way because, on the ground, had no natural enemies, while at sea felt easy prey for sharks. If so, it would mean that the marine iguanas should be pretty hungry to go into the water in search of food. Another explanation was put forward recently. While they are exposed to the sun, marine iguanas regulate their body temperature within limits ranging from 35 to 36 ° C. The temperature of sea water, around the Galapagos, is recorded, for those who are outside, a difference of less than 10 ° C. It also understands that the marine iguanas are reluctant to take refuge in the sea, where dented by such a sudden drop in temperature.