Caiman yacare

Geographic Range

Caiman yacare is mostly differentiated from Caiman crocodilus because of its habitat. Caiman crocodilus is the most widespread of the caiman species. Its range is from the Amazon rainforest in northern South America to Argentina. It is the most abundant crocodilian species in South America.

• Biogeographic Regions
• neotropical neotropical

Habitat

Caiman yacare inhabits jungle areas with high precipitation. They are fixed around permanent bodies of water, typically swamps, wetlands, and rivers. They tend to nest within 200 meters of water or on mats of grass. Their nests move annually or more. When water levels are higher in the wet season and food resources are scarce, caiman tend to disperse in different spots along the water. If the dry season is especially harsh, many could perish with the lack of water available.

• Habitat Regions
• tropical tropical

• Terrestrial Biomes
• rainforest rainforest

• Wetlands
• marsh marsh
• swamp swamp
• bog bog

Physical Description

Caiman yacare used to be classified under Caiman crocodilus , but since has been classified as its own subspecies. Caimans can be distinguished from alligators by their divided eye ridges. It has brown to red colored scaly skin that is extremely valuable for hunters and poachers. The back of this animal is covered in dermal scutes, reaching up to several centimeters high. Another name for Caiman yacare is piranha caiman, because of their crooked teeth. They average about 76 cm for males and 70 cm for females, males being slightly larger and heavier than females. Sexual dimorphism can only be seen in young, as female caimans have much larger heads than males at a young age. Males are born much larger than females. Young also have more distinctive spots along their jaw than adults.

• Other Physical Features
• ectothermic ectothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Development

Caiman yacare lay eggs in mound nests. Incubation typically lasts 60-75 days. Sex is determined by temperature, but is usually impossible to determine when young are smaller than 30cm. Males are born much larger than females at birth. At the age of 10-15 years old, Caiman yacare reaches sexual maturity.

• Development - Life Cycle
• temperature sex determination

Reproduction

There is very little research done on the mating systems of Caiman yacare , although the first major study has discovered the low genetic variance and multiple paternity in this species. They found that mostly dominant males contribute to reproduction. Usually, a female will use polyandry, and will choose several males to mate with. It is believed that females are also capable of sperm storage. Males will sometimes use the water dance used to communicate to attract mates. Females reach reproductive age around 10-15.

• Mating System
• polyandrous polyandrous

Females guard the mound-shaped nests after eggs are laid. Typically, they nest within 200 m of water during the wet season. Clutch size is around 25. The incubation period usually lasts around 60-70 days. During this time, the female may leave the nest for short periods of time, exposing the eggs to predation. Usually, the nests are made on the shore or close by, or on mats of grass floating in the water. Grass mat nests help reduce the risk of predation drastically.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous
• sperm-storing sperm-storing

Female caiman yacare tend to guard nests after eggs are laid. After hatching, parental involvement ceases.

• Parental Investment
• pre-hatching/birth
  • protecting
    • female

Lifespan/Longevity

The yacare caiman’s lifespan has not been extensively studied, but is estimated around 30 years. It is also estimated that they can live up to 50 years in captivity.

Behavior

Scientists have studied the infrasound and communications between Caiman yacare . This includes slapping of water, blowing bubbles, and making other noises to communicate. For longer distance communication, the yacare caiman uses infrasound, vibrating at a very low frequency, inaudible to humans, as well as a dance. There has been no long-term study of behavior of Caiman yacare.

• Key Behaviors
• motile motile
• territorial territorial
• dominance hierarchies dominance hierarchies

Communication and Perception

Vibrations, dancing and infrasounds are used for both mating displays and communications between yacare caimans. Dancing can include blowing bubbles and slapping water. "Water dances," when infrasound produces water disturbances, have not been exclusively studied for its purpose. No extensive research has been done on the senses of Caiman yacare

• Communication Channels
• visual visual
• acoustic acoustic

• Other Communication Modes
• vibrations vibrations

• Perception Channels
• visual visual
• acoustic acoustic
• vibrations vibrations

Food Habits

Since Caiman yacare lives near water, its diet is typically made up of aquatic invertebrates, mostly snails and fish. When eating snails, they will eat the shell as well as the animal itself. Foraging habits change with different climate conditions and availability of food sources. Since South America experiences wet and dry seasons, varying water levels affect accessibility to food sources. Many yacare caimans find food more accessible in the dry season with lower water levels.

• Primary Diet
• carnivore carnivore
  • piscivore piscivore
  • molluscivore molluscivore

• Animal Foods
• fish
• mollusks
• aquatic crustaceans

Predation

There are few animals that prey on Caiman yacare , usually large mammals, such as the jaguar. There are, however, many that feed on the eggs of this caiman. When the mother leaves the nest for a short period of time, many small mammals take advantage of this gap to steal and eat the eggs. Common predators include the crab-eating fox, tayras, and feral pigs. Many yacare caiman nests are made on floating grass mats, drastically dropping the rate of predation on eggs. When nesting in the jungle near the water, predation levels are much higher.

Ecosystem Roles

There is little mention of ecosystem roles in the literature, but one can infer its role from its dietary habits. It is a secondary consumer because it consumes snails and fish, but is eaten by larger mammals, like jaguars. It is a heterotrophic carnivore.

Economic Importance for Humans: Positive

Caiman yacare has been coveted throughout time for their skin for making leather. It is now illegal to hunt these caimans, but is still prevalent. These hunters prefer larger caimans, usually around 80-90 cm. The 1980’s was the most popular time for this illegal harvest. There are many farms that legally raise these reptiles that gained popularity in the 90’s. It is still against the law to hunt Caiman yacare in the wild. Even though population numbers were very low, the laws put in place helped put its conservation status at least concerned. In addition to their valuable skin, their urine and meat are also marketable. Their urine is used in perfumes.

• Positive Impacts
• food food
• body parts are source of valuable material

Economic Importance for Humans: Negative

There is nothing present in the literature about negative impacts on humans. Caiman yacare lives deep in the jungle, usually hard to reach.

• Negative Impacts
• injures humans

Conservation Status

Despite the long history of illegal hunting of Caiman yacare , their conservation status is set at "least concerned." Before regulations, the status was "threatened," such as on the 1970 US Federal List.

Additional Links

Encyclopedia of Life

Contributors

Megan Flanagan (author), University of Wisconsin Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

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