Geographic Range
Paleosuchus palpebrosus
, Cuvier's dwarf caiman, is most commonly found in the wetlands of Brazil, French
Guiana, Surinam, Guyana, and Venezuela. Widespread throughout the Orinoco and Amazon
basins,
P. palpebrosus
inhabit areas extending from Colombia, Venezuela, and the Guianas south to Sao Paulo
and the upper Rio Paraguay in southern Brazil and west to the Rio Pastaza in Ecuador.
- Biogeographic Regions
- neotropical
Habitat
This species can be found near rivers and inundated savanna areas including the Orinoco
and Amazon rivers, as well as those in eastern Paraguay. This species prefers clean,
clear, fast-moving streams or rivers in forested areas containing waterfalls and rapids.
Paleosuchus palpebrosus
mostly inhabit fordable freshwater, avoiding salty, briny waters. It likes cooler
waters compared to other caimans. Across inhabited areas,
P. palpebrosus
has been known to occupy streams of varying sizes, where they are spotted resting
near the shorelines. This species is also terrestrial, and has been seen relaxing
on piles of small rocks and residing near decaying trees. Likewise,
P. palpebrosus
is known to dwell in burrows, which are up to 1.5-3.5 meters long. Populations in
southern Brazil and Venezuela are limited to waters with very low nutrients.
P. palpebrosus
can be found resting on rocks, or in shallow water with its back exposed on the surface
and its head facing the sun. Preferring colder temperatures, they can survive in cool
conditions (as low as 6 degrees Celsius).
- Habitat Regions
- tropical
- terrestrial
- freshwater
- Terrestrial Biomes
- savanna or grassland
- forest
- rainforest
- Aquatic Biomes
- lakes and ponds
- rivers and streams
- Other Habitat Features
- riparian
Physical Description
This species is the smallest of the alligator family. Males grow to about 1.3-1.5 meters, while the females grow to 1.2 meters. They can reach a mass of about 6-7 kg.
Paleosuchus palpebrosus
retain a reddish-brown body color. The dorsal surface is mostly plain and nearly
black, while the upper and bottom jaws are covered with several dark and light spots.
The tail is marked with encircling bands to the tip. Most of these caimans have brown
eyes, but some have also been known to have gold-yellow eyes.
P. palpebrosus
do not have the same dental formula as other caimans. Most caimans have 5 premaxillary
teeth in the upper jaw, but this species only has 4. Scale characteristics allow the
differentiations between all other species.
P. palpebrosus
has 17-20 longitudinal rows on their dorsal and its tail (double crest) has bands
of 7-9 rows.
Paleosuchus palpebrosus
has more
osteoderms
(bony plates) covering its skin than any other species.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
Development
When hatched, the young have almost the identical features as an adult. The sex of
hatchlings is determined by the incubation temperature of the eggs. Differences in
size can be used to differentiate the sexes. Growth continues throughout their lifespan.
The fastest rate of growth occurs during the first 2 years, then declines with age
thereafter. For the first 5 years,
P. palpebrosus
grow at a rate of 6-8 cm per year. It takes approximately 10 years to for one of
these caimans to complete maturity and develop full adult characteristics.
- Development - Life Cycle
- temperature sex determination
Reproduction
Courtship and copulation take place at the end of the dry season. At this time, the
males, are seen to lift their heads high and hold their tails almost vertically out
of the water. The males release what is described to be a "roar"-like sound. The description
of the "roaring" varies, and it commonly heard as simply a grunt-like call. The varying
sounds and noises indicate the actual complexity of mating rituals within this species.
The male, which mates with multiple females, performs distinctive mating displays,
then approaches any receptive female. Rather than during the day,
P. palpebrosus
prefer to mate during the night. Normally in shallow waters, copulation takes place
with the female mounting the male and twisting her tail under his. The actual mating
process can last anywhere between 5-10 minutes or even up to a whole day. It can also
occur repeatedly over several days, after which both male and female settle in the
water for a period. Most females are only able to breed once a year, but on the other
hand, if bred in captivity and fed efficiently, the females are able to breed 2 or
3 times a year.
- Mating System
- polygynous
This species is reported to nest during the dry season, during the wet season, or
all year round, depending on the locality. More specifically, studies show
P. palpebrosus
prefer to nest at the end of the dry season and the beginning of the rainy season
in areas with warm climates. When ready to start nesting, the females stop feeding
and begin the mating process. The females can lay around 10-25 eggs. Both female and
male
P. palpebrosus
build nests for their eggs. These nests are made of soil, usually mud, blended with
fresh and rotten leaves, small branches, and other vegetation. Like other caimans,
this species is a mound-nester where the females lay their eggs and bury them underneath
the mound. These nests are generally small in diameter and height. These eggs are
white, long, and weigh anywhere from 61-70 grams. The eggs hatch after 90 days. The
female opens the nest in response to vocalizations of the young from within the nests.
After the young hatch from their eggs, they continue to stay beneath the debris of
the nest for several days, staying away from the water. It is said that the adults
open the nest and direct their young toward the water, but studies do show the lack
of parental care. The general behavior of adult males are to leave once after the
female lays her eggs. Males do not regularly stay near the females during the hatching
or post-hatching period. Sexual maturity is dependent on size, and relates to age
as it correlates with growth. When a male reaches a size of 1.1 meters, it has become
sexually mature and the females are ready to breed when they are about 1 meter in
length. For
P. palpebrosus
to become completely sexually mature, it could take more than 10 years.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- oviparous
The degree of parental care after hatching varies with local conditions. The nest
is made by both parents. Studies show that the females remain with the hatchling group
for only a few weeks before the hatchlings disperse. Then, the young are left alone
and the mother leaves. The female rarely returns to her nesting site to search for
her young, but can recognize them by smell. The nesting period is very dangerous for
the young. Many predators lurk around nests to snatch eggs for food. In response,
the female and male parents become defensive and take whatever action is necessary
to guard their eggs. The female is always alert and remains near the nest during this
period and will react to the slightest movement. Males do not regularly stay near
the female during the hatching or post-hatching period. Furthermore, captive caimans
are much more aggressive during their nesting period. The female can become very hostile
and charge from the water at any sudden movement near the nest. She remains by the
eggs for long periods, even without an apparent threat. Other defensive behaviors
are tail slapping and splashing water by snapping their jaws. Sometimes,
P. palpebrosus
hatchlings are found alone or in pairs without any parental protection at all.
- Parental Investment
-
pre-fertilization
- provisioning
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- male
- female
-
provisioning
-
pre-weaning/fledging
-
protecting
- female
-
protecting
-
pre-independence
-
protecting
- female
-
protecting
Lifespan/Longevity
The crocodilians are known to have long lifespans. Although
P. palpebrosus
adults are long lived, the exact longevity is not known. Generally, the adults have
been known to live for 20-40 or more years. In captivity this species has a better
longevity than of wild individuals.
Behavior
Paleosuchus palpebrosus
is a social species with diverse and interesting behaviors. Like most crocodilians,
they can convey social messages through sounds, postures, movements, smells, and touch.
Although most crocodilians are somewhat social,
P. palpebrosus
are typically found alone or in pairs. When in pairs or small groups,
P. palpebrosus
are known to migrate long distances due to competition. Systematic studies of adults
indicate that there are dominance hierarchies within groups. The most hostile and
aggressive individuals appear to be the most dominant. These individuals control access
to mates, nest sites, food, and living space. Dominance is asserted and maintained
by social signals and displays. Challenges within a group may occur, but physical
combat is rare. When threatened, this species may inflate its body to exaggerate size
and begin to hiss defensively. Oftentimes, when an individual's status is challenged,
they will compete with each other by holding their bodies in a vertical position above
the water's surface, displaying their size to discourage their opponent from more
aggression.
- Key Behaviors
- terricolous
- natatorial
- nocturnal
- motile
- nomadic
- daily torpor
- territorial
- social
- dominance hierarchies
Home Range
Dominant males defend territories from which they exclude other males. The defended
resources include access to mates, nesting sites, and foraging areas. Territories
may be defended all year round and vary in size with seasonal changes.
Communication and Perception
Communication begins in the egg and continues throughout their entire life. Sound,
postures, motions, and touching are few of the many methods of communication in this
species. Along with vocal signals,
Paleosuchus palpebrosus
communicate via nonverbal sounds, performing actions such as head-slapping or jaw-clapping
at the water's surface. Like most caimans,
P. palpebrosus
males emit a grunt-like "chumph" sound by expelling air through the nostrils during
courtship. When in water, exposure of the head, back, and tail above the surface conveys
important information about an individual's social status and intent.
Food Habits
P. palpebrosus
is a nocturnal hunter, preferring to spend the daylight hours basking. The young
feed on aquatic and shoreline insects of many species. Their food includes tadpoles,
frogs, snails, crabs, shrimp, and small fish. Adults mainly consume tadpoles, frogs,
snails, fish, small mammals, and a wide variety of insects. Diet changes with the
size and age of this species. As an adult, there is an increase in the fish intake
as well as a greater intake of small crabs, birds, reptiles, and small mammals. Like
other crocodilians,
P. palpebrosus
experiment with their food, so they will capture whatever prey is available. Prey
is usually swallowed whole or in large pieces. The stomach enzymes in crocodiles and
alligators are so strong that pH levels are among the lowest ever recorded in any
vertebrate. Another characteristic of
P. palpebrosus
is the amount of
gastroliths
(small stones) inside the stomach. The stones are found only in one chamber of the
stomach, the gizzard, and this one chamber has walls with folds to permit expansion
and contraction. It is said these gastroliths help in the process of digestion, the
stones churn inside the stomach, breaking apart the food.
- Primary Diet
-
carnivore
- eats terrestrial vertebrates
- piscivore
- insectivore
- Animal Foods
- birds
- mammals
- amphibians
- reptiles
- fish
- insects
- terrestrial non-insect arthropods
- mollusks
- terrestrial worms
- aquatic crustaceans
Predation
The most dangerous time in a caiman's life is while it is still in the egg. Without
protection, predators such as rats,
procyonids
, and other carnivores can hastily clean a nest of eggs. If the eggs hatch, the young
are still at a high risk of predation. The young are taken primarily by
wading birds
,
snakes
, and a host of other carnivorous animals. Due to the large number of bony osteoderms
underneath the scales, many predators are not able to swallow this species. The only
predators of adult
P. palpebrosus
are large
boas
,
green anacondas
, and
jaguars
.
Ecosystem Roles
Cuvier's dwarf caiman is considered a "keystone species" that maintains ecosystem
structure and function by selective predation on fish species (such as
piranhas
) that if left unchecked, would transform the ecosystem. Although
P. palpebrosus
is small in size, it is known to have fewer predators than related species because
of its uniquely armored and jagged skin.
- Ecosystem Impact
- keystone species
Economic Importance for Humans: Positive
Although the meat of P. palpebrosus is indeed very palatable, these small animals do not produce enough to be considered beneficial. The skin is also traded to a degree. However, alternatives are usually favored over the small and extremely tough hide of this dwarf caiman. Also hunting Cuvier's dwarf caiman is difficult due to their reclusive, solitary nature and their preference for densely forested habitat.
Small crocodilians such as
Paleosuchus palpebrosus
and
Paleosuchus trigonatus
are currently popular in the pet trade due to their relatively small and theoretically
manageable size.
Economic Importance for Humans: Negative
This species has no negative economic affect on humans.
As pets,
P. palpebrosus
are notoriously hostile and cannot be handled comfortably. Bites from adults are
exceedingly painful.
- Negative Impacts
-
injures humans
- bites or stings
Conservation Status
Right now,
P. palpebrosus
is not considered in need of active conservation. The IUCN rates at as Lower Risk,
and of Least Concern. However the species is listed in Appendix II of CITES, which
regulates international trade in the animals or their parts. The recent removal of
larger, dominant crocodilian species (e.g.
Caiman crocodylus
) may have allowed smaller species like
P. palpebrosus
to expand into habitats from which it formerly was excluded.
Other Comments
This species,
P. palpebrosus
, was first described by the Baron Cuvier in 1807 from Cayenne, French Guiana.
Additional Links
Contributors
David Armitage (editor), Animal Diversity Web.
Heiry Choi (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- freshwater
-
mainly lives in water that is not salty.
- tropical savanna and grassland
-
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
- savanna
-
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
- temperate grassland
-
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- rainforest
-
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
- marsh
-
marshes are wetland areas often dominated by grasses and reeds.
- swamp
-
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
- riparian
-
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- heterothermic
-
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- polygynous
-
having more than one female as a mate at one time
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- natatorial
-
specialized for swimming
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- nomadic
-
generally wanders from place to place, usually within a well-defined range.
- territorial
-
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
- social
-
associates with others of its species; forms social groups.
- dominance hierarchies
-
ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- keystone species
-
a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).
- pet trade
-
the business of buying and selling animals for people to keep in their homes as pets.
- food
-
A substance that provides both nutrients and energy to a living thing.
- carnivore
-
an animal that mainly eats meat
- piscivore
-
an animal that mainly eats fish
- insectivore
-
An animal that eats mainly insects or spiders.
References
Grenard, S. 1991. Handbook of Alligators and Crocodiles . Malabar, Florida: Krieger Publishing Company.
Guggisberg, C. 1972. Crocodiles: Their Natural History, Folklore, and Conservation . Great Britain: David & Charles Limited.
Halliday, T., K. Adler. 2002. The New Encyclopedia of Reptiles and Amphibians . Oxford: Oxford University Press.
Platt, S., T. Rainwater, S. McMurry. 2002. Diet, gastrolith acquisition and initiation of feeding among hatchling Morelet's crocodiles in Belize. Herpetological Journal , 12/2: 81-84.
Santos, S., G. Mourao. 1996. Diets of Caiman crocodilus yacare from different habitats in the Brazilian Pantanal. Herpetological Journal , 6/4: 111-117.
Stevenson, C. 1999. "The Paleosuchus Page" (On-line ). Accessed 03/22/03 at http://crocodilian.com/paleosuchus/ .
Webb, G., C. Manolis, P. Whitehead. 1987. Wildlife Management: Crocodiles and Alligators . Australia: Surrey Beatty & Sons Pty Limited.
Webb, G., C. Manolis. 1998. Australian Crocodiles: A Natural History . Australia: Reed New Holland.