Black caiman
Black caiman | |
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Adult above, juvenile below | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Archosauromorpha |
Clade: | Archosauriformes |
Order: | Crocodilia |
Family: | Alligatoridae |
Subfamily: | Caimaninae |
Clade: | Jacarea |
Genus: | Melanosuchus |
Species: | M. niger
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Binomial name | |
Melanosuchus niger (Spix, 1825)
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Synonyms[4][5] | |
The black caiman (Melanosuchus niger) is a
A
Reproduction takes place in the
Characteristics
The black caiman has dark-coloured, scaly skin. The skin coloration helps with
The black caiman is structurally dissimilar to other caiman species, particularly in the shape of the skull. Compared to other caimans, it has distinctly larger eyes. Although the snout is relatively narrow, the skull (given the species' considerably larger size) is much larger overall than other caimans. Black caimans are relatively more robust than other crocodilians of comparable length. There appears to be varying skull morphology in this species depending on the age and particular individual animal, which is not uncommon in other modern crocodilians, and by gender, with adult males typically having much more massive skulls relative to their size than like-age females. Due to the differences, males have a stronger bite force and likely exploit a different, and larger, prey base than females.[14] Young black caiman can be distinguished from large spectacled caimans by their proportionately larger head, as well as by the colour of the jaw, which is light coloured in the spectacled caiman and dark with three black spots in the black caiman.[12] A 3-metre (10 ft), 103-kilogram (227 lb) black caiman was found to have a bite force of 4,310 N (970 lbf).[15]
Size
The black caiman is the largest predator in the Amazon basin and the largest member of the Alligatoridae family, making it one of the largest extant reptiles.[16][17] It is also significantly larger than other caiman species. Most adult black caimans are 2.2 to 4.3 m (7 ft 3 in to 14 ft 1 in) in length, with a few old males exceeding 5 m (16 ft 5 in). Sub-adult male specimens of around 2.5 to 3.4 m (8 ft 2 in to 11 ft 2 in) will weigh roughly 95 to 125 kg (209 to 276 lb), around the same size as a mature female, but will quickly increase in bulk and weight. The average size of adult females at their nests was found to be 2.8 m (9 ft 2 in).[18] Mid-sized mature males of 3.5 to 4 m (11 ft 6 in to 13 ft 1 in) weigh approximately 300 kg (660 lb), while large mature specimens exceed 400 to 500 kg (880 to 1,100 lb), being relatively bulky crocodilians.[19][20][21] Very large, old males can exceed 5 m (16 ft 5 in) in length, and weigh up to 750 kg (1,650 lb).[22] A relatively small adult male of a total length of 3.4 m (11 ft 2 in) weighed 98 kg (216 lb) while an adult male considered fairly large at a length of 4.2 m (13 ft 9 in) weighed approximately 350 kg (770 lb).[20][23] Another sampling of sub-adult males found them to range in length from 2.1 to 2.8 m (6 ft 11 in to 9 ft 2 in), averaging 2.45 m (8 ft 0 in), and that they weighed from 26 to 86 kg (57 to 190 lb), averaging 48 kg (106 lb).[24] In a study conducted in Rupununi River, Guyana, sub-adult and adult black caimans ranged from 2.03 to 3.71 m (6 ft 8 in to 12 ft 2 in) in length and weighed between 18 and 210 kg (40 and 463 lb).[25] In some areas (such as the Araguaia River) this species is consistently reported at 4 to 5 m (13 ft 1 in – 16 ft 5 in) in length, although specimens this size are uncommon. Several widely reported but unconfirmed (and probably largely anecdotal) reports claim that the black caiman can grow to over 6.1 m (20 ft 0 in) in length and weigh up to 1,100 kg (2,400 lb).[11][12][26] While it is unclear what the sources for this maximum size are, many scientific papers accept that this species can attain extreme sizes as such.[27][28][29] In South America, two other crocodilians reportedly reach similar sizes: the American crocodile (Crocodylus acutus) and the Orinoco crocodile (C. intermedius).
Biology and behaviour
Hunting and diet
Black caimans are
Reproduction
At the end of the dry season, females build a nest of soil and vegetation, which is about 1.5 m (4.9 ft) across and 0.75 m (2.5 ft) wide. They lay up to 65 eggs (though usually somewhere between 30 and 60), which hatch in about six weeks, at the beginning of the wet season, when newly flooded marshes provide ideal habitat for the juveniles once hatched.[12] The eggs are quite large, averaging 144 g (5.1 oz) in weight.[18] Unguarded clutches (when the mother goes off to hunt) are readily devoured by a wide array of animals, regularly including mammals such as South American coatis (Nasua nasua) or large rodents, egg-preying snakes and birds such as herons and vultures. Occasionally predators are caught and killed by the mother caiman.[12] Hatching is said to occur between 42 and 90 days after the eggs are laid.[12] It is well documented that, as with other crocodilians, caimans frequently move their young from the nest in their mouths after hatching (whence the erroneous belief that they eat their young), and transport them to a safe pool. The mother will assist chirping, unhatched young to break out of the leathery eggs, by delicately breaking the eggs between her teeth. She will try to look after her young for several months but the baby caimans are largely independent and most do not survive to maturity. Baby black caimans are subject to predation even more regularly after they hatch, facing many of the same mesopredators, as well any other crocodilian (including those of their own species), large snake or large, carnivorous fish that they encounter. Predation is so common that black caimans count on their young to survive via safety in numbers.[12] The female black caiman only breeds once every 2 to 3 years. During the dry season throughout the Black Caimans reproduction season, they will give off a sound that closely resembles like rumbling thunder in order to communicate with others.[48]
Interspecific predatory relationships
Many predators, including various fish, mammal, reptile and even amphibian species, feed on caiman eggs and hatchlings. The black caiman shares its habitat with at least 3 other semi-amphibious animals considered
Conservation status and threats
Humans hunt black caimans for leather or meat. This species was classified as Endangered in the 1970s due to the high demand for its well-marked skin. The trade in black caiman leather peaked from the 1950s to 1970s, when the smaller but much more common spectacled caiman (Caiman crocodilus) became the more commonly hunted species. Local people still trade black caiman skins and meat today at a small scale but the species has rebounded overall from the overhunting in the past.[18] That black caimans lay, on average, around 40 eggs has helped them recover to some degree.[18] Perhaps an equal continuing threat is habitat destruction, since development and clear-cutting is now epidemic in South America. Spectacled caimans have now filled the niche of crocodilian predator of fish in many areas. Due to their greater numbers and faster reproductive abilities, the Spectacled populations are locally outcompeting black caimans, although the larger species dominates in a one-on-one basis.[12] Persistent management is needed to control caiman-hunting and is quite difficult to enforce effectively.[18] After the depletion of the black caiman population, piranhas and capybaras, having lost perhaps their primary predator, reached unnaturally high numbers. This has, in turn, led to increased agricultural and livestock losses.[12]
Compounding the conservation issues it faces, this species occasionally preys on humans.[54] Most tales are poorly documented and unconfirmed but, given this species' formidable size and strength, attacks on humans are quite often fatal.[23][13][55]
The species is uncommon in captivity and breeding it has proven to be a challenge. The first captive breeding outside its native range was at Aalborg Zoo in 2013.[56]
Notes
- ^ Except the populations of Brazil and Ecuador which are included in Appendix II.
See also
References
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- ^ Boulenger GA (1889). Catalogue of the Chelonians, Rhynchocephalians, and Crocodiles in the British Museum (Natural History). New Edition. London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). x + 311 pp. + Plates I–VI. (Caiman niger, pp. 292–293).
- ^ "Melanosuchus niger ". The Reptile Database. www.reptile-database.org.
- ISBN 978-0-19-066829-7.
- ^ Black Caiman (Melanosuchus niger). Crocodilian Specialist Group. Retrieved on 2013-04-13.
- ^ a b c Melanosuchus niger Black caiman. Animal Diversity Web. Retrieved on 2013-04-13.
- ^ "Arkive closure". Archived from the original on 2017-09-06. Retrieved 2018-03-09.
- ^ Black Caiman (Melanosuchus niger). Crocodile Specialist Group.
- ^ a b Black Caiman, Black Caiman Skull. Dinosaurcorporation.com. Retrieved on 2012-08-23.
- ^ a b c d e f g h i j Crocodilian Species – Black Caiman (Melanosuchus niger) Archived 2017-10-31 at the Wayback Machine. Crocodilian.com. Retrieved on 2012-08-23.
- ^ a b Sideleau B, Britton ARC (2012). "A preliminary analysis of worldwide crocodilian attacks". pp. 111–114. In: Crocodiles. Proceedings of the 21st Working Meeting of the Crocodile Specialist Group, Manila, Philippines. IUCN. Gland, Switzerland, Manila, Philippines.
- ^ Foth, C., Bona, P., & Desojo, J. B. (2015). Intraspecific variation in the skull morphology of the black caiman Melanosuchus niger (Alligatoridae, Caimaninae). Acta Zoologica, 96(1), 1-13.
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- ^ a b c d e Thorbjarnarson JB (2010). "Black Caiman Melanosuchus niger ". pp. 29–39. In: Manolis SC, Stevenson C (editors). Crocodiles. Status Survey and Conservation Action Plan. Third edition. Darwin: Crocodile Specialist Group. iucncsg.org
- ^ French Guiana. kwata.net (2003).
- ^ a b Da Silveira, R., Do Amaral, J.V., Mangusson, W.E. & Thorbjarnarson, J.B. (2011). Melanosuchus niger: Signaling Behavior & Long-Distance Movement. Herpetological Review, 42 (3): 424-425.
- ^ Sirder, H. (2014). Le Caiman noir, Espèce transamazonienne. Livret édité par le Parc naturel régional de la Guyane dans le cadre du programme OYAN, Parque nacional Cabo Orange.
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- ^ Da Silveira, R., Magnusson, W. E., & Campos, Z. (1997). Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil. Journal of Herpetology, 514-520.
- ^ Barker, G. M. (Ed.). (2004). Natural enemies of terrestrial molluscs. CABI.
- ^ Junk, W. J., & da Silva, V. M. F. (1997). Mammals, reptiles and amphibians. In The Central Amazon Floodplain (pp. 409-417). Springer, Berlin, Heidelberg.
- ^ "Melanosuchus niger (Black caiman)". Animal Diversity Web.
- ^ "Black Caiman (Melanosuchus niger)".
- ^ Horna JV, Cintra R, Ruesta PV (2001). "Feeding ecology of black caiman Melanosuchus niger in a western Amazonian forest: The effects of ontogeny and seasonality on diet composition". Ecotropica. 7: 1–11.
- ^ Horna V, Zimmermann R, Cintra R, Vásquez P, Horna J (2003). "Feeding ecology of the black caiman (Melanosuchus niger) in Manu National Park, Peru". Lyonia. 4: 65–72.
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- ^ Reynolds N (2008). Dietary competition between the black caiman (Melanosuchus niger) and the spectacled caiman (Caiman crocodilus) within the Lago Preto Reserve, Peru. DI512 Dissertation.
- ^ Wright, L. (1982). The IUCN Amphibia-Reptilia red data book (Vol. 1). IUCN.
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- ^ Black Caiman. Adapting Eden. Retrieved on 2015-09-25.
- ^ Potts, Ryan J. "Endangered Reptiles and Amphibians of the World – II. The Black Caiman, Melanosuchus niger ". Vermont Herpetology.
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- ^ Rosenblatt, Adam (November 15, 2021). "What do adult black caiman (Melanosuchus niger) actually eat?". Biotropica. 54 (1).
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- ^ TV2 Nord (12 September 2013). Sjældne kaimanunger kan nu ses af publikum. Retrieved 23 April 2017. (in Danish).
Further reading
- Spix JB (1825). Animalia nova sive species novae lacertarum, quas in itinere per Brasiliam annis MDCCCXVII – MDCCCXX jussu et auspiciis Maximiliani Josephi I. Bavariae Regis suscepto collegit et descripsit. Munich: F.S. Hübschmann. Index (4 unnumbered pages) + 26 pp. + 30 color plates. (Caiman niger, new species, pp. 3-4 + Plate IV). (in Latin).
External links
- The Night of the Caimans, from International Wildlife Federation.