The Spectacled Caiman (Caiman crocodilus)

Jun 26, 2011 Features / Columnists, Interesting Creatures in Guyana

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The Spectacled Caiman (Caiman crocodilus), also known as the White Caiman or Common Caiman, is a crocodilian reptile found in much of Central and South America. It lives in a range of lowland wetland and riverine habitat types and can tolerate salt water as well as fresh; due in part to this adaptability it is the most common of all crocodilian species. Males of the species are generally 2 to 2.5 metres (6.6 to 8.2 ft), while females are smaller, usually around 1.4 metres (4.6 ft).
The species’ common name comes from a bony ridge, between the eyes, which gives the appearance of a pair of spectacles.
They have been known to change colour. During colder weather the black pigment, found within their skin cells, will expand making them darker.
REPRODUCTION
The Spectacled Caiman will reach sexual maturity anywhere from 4 to 7 years. Usually the more dominant individuals will mature more quickly. They will gather and mate during the dry season. After mating season ends the females will build nests out of dense vegetation. The size of the nest varies depending on the resources available to the female. Each female can lay up to forty eggs. The larger females have recently been found to lay eggs that are larger than the eggs smaller females lay. Most Caimans will nest during the wet season. It is very unusual to see a Caiman nest during any winter months. The temperature is too low for the eggs.
Temperature is important to the developing eggs. Females will build their nests in a way that insulates them from extreme temperature changes. The nests are made of vegetation, as the vegetation decays the nests produce heat which can keep the eggs about five degrees warmer than if they were insulated by mud alone. Temperature not only incubates the eggs, but also determines the sex of the developing Caiman.
Caiman do not possess the genes necessary to determine sex. They depend on temperature. When the temperature inside the nest is approximately 31 degrees Celsius, or lower, the Caiman will become male. However, when the temperature is approximately 32 degrees Celsius or higher they become female. Young Caiman do not hatch with the dark green colouring of their parents. They are yellow with black spots. This colouration will eventually fade away.
Spectacled caiman have strongly protective maternal behaviour. They raise their young in crèches, one female taking care of her own as well as several others’ offspring. They will take care of their young for the first two to four months after the eggs hatch. This is the time it takes for the floods of the wet season to subside.
DIET
Caiman eat a variety of invertebrates such as insects, crustaceans, and mollusks. The larger caiman will eat fish and water snails. Older animals are capable of taking larger, mammalian prey (e.g. wild pigs). Observations show that as conditions become drier, caiman stop feeding. In areas where this species has become depleted, fish populations have also shown a decline. Until recently, it was thought that the Caiman crocodilus would over-eat the fish and snail populations. Some suggest that they control piranha populations. However, piranhas have not been found to be a normal meal.
CONSERVATION
This species benefits from over-hunting of competitive species who occupy the same home range. This allows them access to resources that normally would have been lost to these other species. Their skin is not wanted for leather production because it contains osteoderms. The only skin on their body which does not contain osteoderms is their sides. Therefore hunting of this species is relatively low.
In most countries, hunting this species is legal. Venezuela permits hunting every fall, providing the number of kills does not exceed 150,000 for that season. The skin that is salvageable, will be harvested.
There are about four million Common Caiman found in Venezuela. Recent surveys show that the population is expected to continue to increase. This is an example of how well the species is able to adapt. However, it is difficult to determine how well the species is doing on a global scale since populations are not doing well in other countries.
Despite being commonly mistaken as this species, the incredibly large population of caiman living within the Brazilian Pantanal are a separate species, the Yacare Caiman. More up-to-date surveys are required for clarification, and to examine the interactions between the different subspecies. Further taxonomic work would make control measures easier to implement, as currently identification of different subspecies can be difficult. The major threat to this species and its subspecies is currently illegal hunting.
Conservation programs are utilized in many countries. The most common form of conservation is the use of cropping, or manually the reducing numbers of several wild, and abundant species. Long-term effects have yet to be discovered; more surveys have been recommended. There are also farming or ranching programs, however, they seem to be more expensive and possibly less effective.
(Source: Wikipedia, the free encyclopedia)

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