Neotropical otter

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Neotropical otter
Lontra longicaudis 4.jpeg
At the Corrientes Zoo, Argentina
CITES Appendix I (CITES) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Mustelidae
Genus: Lontra
Species:
L. longicaudis
Binomial name
Lontra longicaudis
(Olfers, 1818)
Neotropical Otter area.png
Neotropical otter range

The neotropical otter or neotropical river otter (Lontra longicaudis) is a near-threatened (per the IUCN) otter species found in freshwater systems from Mexico and Central America through mainland South America, as well as the island of Trinidad. It is physically similar to the northern (L. canadensis) and southern river otter (L. provocax), which occur directly north and south of this species' range, respectively. Its head-to-body length can range from 36–66 centimetres (14–26 in), plus a tail of 37–84 centimetres (15–33 in). Body weight ranges from 5–15 kilograms (11–33 lb). [3]

Contents

Neotropical otters are lactating mammals of the weasel family Mustelidae, the most diverse family in the order Carnivora; the Mustelidae are part of a suborder known as Caniformia, a grouping of carnivorans which includes canids (dogs, wolves, etc.), bears, pinnipeds (seals, walruses), procyonids (raccoons, coatis, kinkajous) and the red panda.

The neotropical otter is found in many different riverine habitats and riparian zones, including those in tropical and temperate deciduous to evergreen forests, savannas, llanos (of Colombia and Venezuela) and the pantanal (in Bolivia, Brazil and Paraguay). It prefers to live in clear, fast-flowing rivers and streams, preferably away from competition with the more boisterous giant otter (Pteronura brasiliensis). Unlike other otters (including the aforementioned giant species), which live in large and cohesive socio-familial units, the neotropical otter is a relatively solitary animal, feeding mostly on fish and crustaceans.

Taxonomy

The taxonomy of the genus Lontra has been debated, but the use of Lontra rather than Lutra for New World otters is generally supported. The Neotropical otter has a very wide range, covering a large portion of South America, so it is not surprising there are geographical structures separating some populations. One such geographical isolation is the Cordillera Mountains. Additionally, the river in the Magdellena river valley flows north, away from the mountains, decreasing the likelihood that otters in the northern tip of South America will mix with otters elsewhere in the continent.

Neotropical otters have an unusual phylogenic relationship to other otter species. They are most similar to marine otter (Lontra felina) and southern river otter (Lontra provocax), which is not surprising considering these two species are found in South America. However, Neotropical otters are relatively distantly related to giant otter (Pteronura brasiliensis), which is surprising considering they have nearly identical ecological niches and home ranges. [4]

Subspecies

In one study, otters within a 1,600 sq mi (4,100 km2) area in southern Brazil showed low nucleotide variation, but high haplotype diversity compared to other otter species and other carnivores. The study made the conclusion that otters may be undergoing a recent increase in diversity. The results also show interrelatedness of otters nearby and give reason to separate the species into subspecies: [5]

Description

The Neotropical otter is covered in a short, dark grayish-brown pelage. Fur color is lighter around the muzzle and throat. [6] They possess a long wide tail, with short stout legs and fully webbed toes. Sexually dimorphic, the males are about 25% larger than the females. [7] Its head-and-body length can range from 36–66 centimetres (14–26 in), plus a tail of 37–84 centimetres (15–33 in). [3] Body mass of the otter generally ranges from 5 to 15 kilograms (11–33 pounds). Neotropical otters will communicate with nearby otters via scent marking. Communication may also occur via whistles, hums, and screeches. [7]

The dental formula seldom varies from that of Eurasian otters (Lutra lutra), except in the few cases of otters that have dental anomalies. [8] Females and males have the same formula. The dental formula (for half the skull) is as follows: [9]

Distribution and habitat

A neotropical otter in Bioparque Ukumari, Colombia Nutria zona de conservacion.jpg
A neotropical otter in Bioparque Ukumarí, Colombia

The Neotropical otter has the widest distribution of all the Lontra species. Their habitat can range from northwest Mexico to central Argentina. They prefer clear, fast-flowing rivers, and are rarely known to settle in sluggish, silt-laden lowland waters or boggy areas. While mostly occurring at 300–1,500 m (980–4,900 ft) above sea level, they have been found settled at 3,000 m (9,800 ft). [10] They require dense riparian vegetation and abundant den sites but, other than that, the Neotropical otter is very versatile and tolerant to environmental change. The otters prefer den sites that are solid, high, dry, and in proximity to deep water. [11] The Neotropical otter is the greatest generalist of all otter species. In addition to rivers and streams, they can settle in and exploit some rather formidable habitats, such as wastewater treatment plants, rice paddies, sugar cane plantations, estuaries, deltas, drainage ditches, and sometimes swamps. They can inhabit cold, glacial lakes and streams in the Andes of Ecuador and Colombia. [12] Neotropical otters will also venture to the seashore and beaches (maintaining an almost "brackish" lifestyle), hunting marine creatures and playing in the highly saline water. [13]

Ecology and behaviour

Diet

The Neotropical otter's diet consists mostly of fish and crustaceans making up 67% and 28%, respectively, of its total diet. The otter will also occasionally feed on mollusks and small mammals, as well as birds, large insects and fruits. [14] [15] This otter is known to occasionally attack fishnets for a source of prey, hindering fishing productivity. [13] Otters living near marine habitats can have a much higher proportion of crustaceans in their diets.

Seasonality also greatly affect otters' food choice. During the dry season, when less fish and crustaceans are available, one study found a higher proportion of frogs in otters' diet. Though, during this time, anurans and reptiles still made up a very small percentage of the total diet. This might also be due to the fact that certain frogs mate during the dry season, so the frogs are easier prey. All in all, the distribution of available food species in a particular area roughly correlates to the percentage of each species found in otters' diet. [16]

Reproduction

Breeding occurs mostly in spring. Gestation will last 56 days and produce a litter of 1–5 pups. [6] The pups are born blind yet fully furred. They will emerge from their mother's nest when about 52 days and begin swimming at 74 days. They are raised completely by their mother, as males do not provide any parental care. [11] The male will only spend a single day with the female during breeding season. The female must keep her pups safe from predation by other Neotropical otters. In one captive breeding situation, cannibalism by the mother may have occurred, though it was not confirmed. [17]

In an ecologically healthy area, there are many possible shelters so an individual can choose its preferred den. However, studies show that not all possible shelters are occupied and not all shelters are equally utilized by Neotropical otters. Otters visit different shelters with varying frequencies, from once or few times per up to many times per year. One factor that influences their preference for a den has to do with the water level, especially during flood season, when a den near water level can easily be washed away. A den may be at the water level, near the bank, or more than 1.5 meters about the water level. [18]

There are many other factors influencing otters' preferences for a shelter. Neotropical otters prefer dens near fresh water, high food availability, and relatively deep and wide water. During seasons with low water, individual otters may be more clumped because they will all move into areas of a river with deeper water, with more fish. [18] Deep, wide pools have been found to have a greater diversity of fish, preferential for otters. Some studies show that otters will forgo a less preferable, but more available den, like a muddy river bank, to spend more time in a preferential den, like a rocky shore. [19]

Neotropical otter females will rear pups in a den without a male. In some cases, a female may find a den that has space to keep her pups and a separate area for her own space. A study of a male otter's movement over 35 days showed he used three different dens without communication between them. Also, this individual moved between two islands separated by a one-kilometer wide estuary. He spent some time in a site with heavy mud, poor substrate for a den, so he may have been on the move to find food. [20]

Dens may have more than one opening, so the otter can easily exit to forage for food while staying safe from predators. There are many classifications of dens that Neotropical otters may use. A cavity among stones or under tree roots is preferred. In certain parts of South America, an otter may come across a limestone dissolution cavity or a cavity in a rocky wall. Though lacking a source of light, the Neotropical otter can make great use of this sturdy home. As a last resort, an otter expend energy to excavate a space among vegetation or a river bank, though those homes are less sturdy. Vegetative cover is also very important for the Neotropical otter. In comparison to other otter dens, the Neotropical otter dens do not have holes directly into the water, they do not use plant material as bedding, and will live in caves without light. They are elusive creatures and prefer undisturbed forests without signs of human activity. When humans clear forests for agricultural land, the number of available otter habitats plummets. [18]

Communication

Like other otter species, Neotropical otters will mark their territory with scratching or spraint (feces) in obvious places like rocks and under bridges. [21] Signs of marking may be most concentrated around their dens. They tend to only mark in certain areas of the den, separate from the activity center of the den. In caves, where a water sources may leak through the walls and wash away the scent, the resident may mark areas inside their den. [18]

Competition

The niches and ranges of the giant otter and the Neotropical otter overlap widely. Both species are diurnal and mainly piscivorous. The giant otter is less of a generalist in habitat, preferring slow-moving water and overhanging vegetation, but where the Neotropical otter may also occur. The giant otter is much larger and hunts in groups, so it can take larger prey. Some areas, like the Pantanal, have high enough productivity such that both otter species can coexist with little or no competition (niche partitioning). Additionally, Neotropical otters prefer deeper and wider streams than giant otters. [12]

Conservation

The Neotropical otter is listed as Near Threatened by the IUCN. The species is currently protected in Argentina and many other South American countries. Heavy hunting for its fur in the 1950s–1970s resulted in much local extinction over the otter's range. Illegal hunting, habitat destruction through mining and ranching, and water pollution still affect the population of the Neotropical otter. [22] Although there have been attempts at captive breeding, these attempts have been largely unsuccessful. [6]

Most negative feelings about otters arise from fishermen who compete with the otter for fish. More data is needed to determine how much overlap exists between the fishermen's desired catch and the otter's diet. The highest competition between Neotropical otters and fishermen occurs during drought conditions. Fishermen may move out of their regular fishing areas, into deeper pools where the otter usually hunts in the absence of people. In a study on local fishermen's attitudes, the study revealed that fishermen's knowledge aligned with scientific data about the Neotropical otter's behavior, body description, and other data. Because the fishermen's facts aligned with scientific knowledge, scientists could then trust the fishermen's first-hand accounts about problems they experience with otters. Fishermen reported that otters will damage their fishing gear, but do not damage crab and shrimp nets. The locals have varying opinions about the otters' presence, from understanding they have to share space with the otters to wanting to kill the otters. There have been proposals to subsidize their fish profits lost to otters. However, it might be more beneficial to pay them to collect data on the species. This would benefit fishermen economically, improve fishermen's attitude towards them, and build on to currently insufficient data about this species. Otters are rarely get caught in gillnets, and when they do they very rarely die. [23]

Neotropical otters are threatened by habitat degradation associated with: agriculture, soil compaction, pollution, roadways, and runoff. Also, when forests are cleared for cattle grazing, heavy vegetation (which is the otter's preferred habitat) near streams is also cleared or trampled by cattle. This species is a very important ecological indicator because they prefer ecologically rich, aquatic habitats and have a low reproductive potential. [19]

In captivity

One male and one female Neotropical otter were captured near Caucasia, Colombia, and taken to Santa Fe Zoological Park in 1994 and 1996, respectively. Zoo staff observed the pair mating in the water, then separated the animals. The female had three births; one was successful. The infant deaths may have been unintentionally caused by the mother. One idea suggested the mother's enclosure was too small and she had no access to water, as she would have had in the wild. The mother's gestation period was 86 days for two separate breeding events recorded at this zoo. An 86-day gestation period is much longer than the previously accepted belief that gestation lasts around 60 days. Two possible explanations are: differences might exist between different subspecies or a later copulation may have occurred and not been observed. Also, this otter species might display short-term variation in gestation periods. [17]

Related Research Articles

<span class="mw-page-title-main">Otter</span> Subfamily of mammals (Lutrinae)

Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine. Lutrinae is a branch of the Mustelidae family, which includes weasels, badgers, mink, and wolverines, among other animals.

<span class="mw-page-title-main">Asian small-clawed otter</span> Species of mammal

The Asian small-clawed otter, also known as the oriental small-clawed otter and the small-clawed otter, is an otter species native to South and Southeast Asia. It has short claws that do not extend beyond the pads of its webbed digits. With a total body length of 730 to 960 mm, and a maximum weight of 5 kg (11 lb), it is the smallest otter species in the world.

<i>Lontra</i> Genus of carnivores

Lontra is a genus of otters from the Americas.

<span class="mw-page-title-main">North American river otter</span> Species of semi-aquatic mammal

The North American river otter, also known as the northern river otter and river otter, is a semiaquatic mammal that lives only on the North American continent, along its waterways and coasts. An adult North American river otter can weigh between 5.0 and 14 kg. The river otter is protected and insulated by a thick, water-repellent coat of fur.

<span class="mw-page-title-main">Eurasian otter</span> Species of carnivore

The Eurasian otter, also known as the European otter, Eurasian river otter, European river otter, common otter, and Old World otter, is a semiaquatic mammal native to Eurasia and Maghreb. The most widely distributed member of the otter subfamily (Lutrinae) of the weasel family (Mustelidae), it is found in the waterways and coasts of Europe, many parts of Asia, and parts of northern Africa. The Eurasian otter has a diet mainly of fish, and is strongly territorial. It is endangered in some parts of its range, but is recovering in others.

<span class="mw-page-title-main">Crab-eating fox</span> Species of carnivore

The crab-eating fox, also known as the forest fox, wood fox, bushdog or maikong, is an extant species of medium-sized canid endemic to the central part of South America since at least the Pleistocene epoch. Like South American foxes, which are in the genus Lycalopex, it is not closely related to true foxes. Cerdocyon comes from the Greek words kerdo and kyon (dog) referring to the dog- and fox-like characteristics of this animal.

<i>Lutra</i> Genus of carnivores

Lutra is a genus of otters, one of seven in the subfamily Lutrinae.

<span class="mw-page-title-main">Pampas fox</span> Species of carnivore

The Pampas fox, also known as grey pampean fox, Pampas zorro, Azara's fox, or Azara's zorro, is a medium-sized zorro, or "false" fox, native to the South American Pampas. Azara in some of its alternative common names is a reference to Spanish naturalist Félix de Azara.

<span class="mw-page-title-main">Giant otter</span> Species of mammal

The giant otter or giant river otter is a South American carnivorous mammal. It is the longest member of the weasel family, Mustelidae, a globally successful group of predators, reaching up to 1.8 m. Atypical of mustelids, the giant otter is a social species, with family groups typically supporting three to eight members. The groups are centered on a dominant breeding pair and are extremely cohesive and cooperative. Although generally peaceful, the species is territorial, and aggression has been observed between groups. The giant otter is diurnal, being active exclusively during daylight hours. It is the noisiest otter species, and distinct vocalizations have been documented that indicate alarm, aggression, and reassurance.

<span class="mw-page-title-main">Marine otter</span> Species of South American mammal (Lontra felina)

The marine otter is a rare and relatively unknown South American mammal of the weasel family (Mustelidae). The scientific name means "feline otter", and in Spanish, the marine otter is also often referred to as gato marino: "marine cat". The marine otter only lives in saltwater, coastal environments and rarely ventures into fresh water or estuarine habitats. This saltwater exclusivity is unlike most other otter species, except for the almost fully aquatic sea otter of the North Pacific.

<span class="mw-page-title-main">Aquatic mammal</span> Mammal that dwells partly or entirely in bodies of water

Aquatic and semiaquatic mammals are a diverse group of mammals that dwell partly or entirely in bodies of water. They include the various marine mammals who dwell in oceans, as well as various freshwater species, such as the European otter. They are not a taxon and are not unified by any distinct biological grouping, but rather their dependence on and integral relation to aquatic ecosystems. The level of dependence on aquatic life varies greatly among species. Among freshwater taxa, the Amazonian manatee and river dolphins are completely aquatic and fully dependent on aquatic ecosystems. Semiaquatic freshwater taxa include the Baikal seal, which feeds underwater but rests, molts, and breeds on land; and the capybara and hippopotamus which are able to venture in and out of water in search of food.

<span class="mw-page-title-main">Hairy-nosed otter</span> Species of otter native to Southeast Asia

The hairy-nosed otter is a semiaquatic mammal native to Southeast Asia and one of the rarest and least known otter species. It is threatened by loss of natural resources and poaching.

<span class="mw-page-title-main">Southern river otter</span> Species of semi-aquatic mammal

The southern river otter, or South American river otter, is an otter species that lives in the southern regions of Argentina and Chile, including parts of Patagonia and Tierra del Fuego. It is listed by the International Union for Conservation of Nature as an endangered species.

<span class="mw-page-title-main">Spotted-necked otter</span> Species of carnivore

The spotted-necked otter, or speckle-throated otter, is an otter native to sub-Saharan Africa.

<span class="mw-page-title-main">African clawless otter</span> Species of carnivore

The African clawless otter, also known as the Cape clawless otter or groot otter, is the second-largest freshwater otter species. It inhabits permanent water bodies in savannah and lowland forest areas through most of sub-Saharan Africa. It is characterised by partly webbed and clawless feet, from which their name is derived. The word 'aonyx' means clawless, derived from the prefix a- ("without") and onyx ("claw/hoof").

<span class="mw-page-title-main">Smooth-coated otter</span> Species of carnivore

The smooth-coated otter is a freshwater otter species from regions of South and Southwest Asia, with the majority of its numbers found in Southeast Asia. It has been ranked as "vulnerable" on the IUCN Red List since 1996, as it is threatened by habitat loss, pollution of wetlands and poaching for the illegal wildlife trade. As the common name indicates, its fur is relatively smooth, and somewhat shorter in length than that of other otter species.

<i>Megalenhydris</i> Extinct genus of giant otter

Megalenhydris barbaricina is an extinct species of giant otter from the Late Pleistocene of Sardinia. It is known from a single partial skeleton, discovered in the Grotta di Ispinigoli near Dorgali, and was described in 1987. It was larger than any living otter, exceeding the size of South American giant otters (Petrolutra), which can reach two meters in length. The species is one of four extinct otter species from Sardinia and Corsica. The others are Algarolutra majori, Lutra castiglionis and Sardolutra ichnusae. It is suggested to have ultimately originated from the much smaller European mainland species "Lutra" simplicidens, which may be more closely related to Lutrogale than to modern Lutra species. The structure of the teeth points to a diet of bottom dwelling fish and crustaceans. A special characteristic of the species is the flattening of the first few caudal vertebrae. This might point to a slightly flattened tail.

Lontra weiri is a fossil species in the carnivoran family Mustelidae from the Hagerman Fossil Beds of Idaho. It shared its habitat with Satherium piscinarium, a probable ancestor of the giant otter of South America. It is named in honor of musician Bob Weir, and is the oldest known member of its genus. Prior to its discovery, Lontra was thought to have evolved from Lutra licenti, which dates from the Pleistocene of East Asia.

References

  1. ↑ Rheingantz, M.L.; Trinca, C.S. (2015). "Lontra longicaudis". IUCN Red List of Threatened Species . 2015: e.T12304A21937379. doi: 10.2305/IUCN.UK.2015-2.RLTS.T12304A21937379.en . Retrieved 19 November 2021.
  2. ↑ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. 1 2 Berry, K. (2000). Lontra longicaudis. Animal Diversity Web
  4. ↑ Trinca, C. S.; De Thoisy, B.; Rosas, F. C. W.; Waldemarin, H. F.; Koepfli, K. -P.; Vianna, J. A.; Eizirik, E. (2012). "Phylogeography and Demographic History of the Neotropical Otter (Lontra longicaudis)". Journal of Heredity. 103 (4): 479–92. doi: 10.1093/jhered/ess001 . PMID   22589556.
  5. ↑ Trinca, C. S.; Waldemarin, H. F.; Eizirik, E. (2007). "Genetic diversity of the Neotropical otter (Lontra longicaudis Olfers, 1818) in Southern and Southeastern Brazil". Brazilian Journal of Biology. 67 (4): 813–8. doi: 10.1590/S1519-69842007000500003 . PMID   18278347.
  6. 1 2 3 Bertonatti,C., and A. Parera. (1994). Lobito de rio. Revista Vida Silvestre. Nuestro libro rojo, fundacion vida silvrestre Argentina, Ficha No. 34
  7. 1 2 Emmons, Louise H.; Feer, François (1997-09-02). Neotropical rainforest mammals. A field guide (2nd ed.). Chicago: University of Chicago Press. pp. 161–162. ISBN   978-0-226-20721-6. OCLC   44179508.
  8. ↑ Peters, F. B., Coelho, E. L., Vasconcelos, B. C. E., Roth, P. R. O., & Christoff, A. U. (2013). Dental anomalies in Lontra longicaudis (carnivora: mustelidae) collected in southern Brazil. IUCN Otter Specialist Group Bulletin, 30(1), 31–36.
  9. ↑ Melissen, A. (2000). Husbandry guidelines for Lutra lutra. Otterspecialistgroup.org
  10. ↑ Eisenberg, J.F. Mammals of the neotropics. The University of Chicago Press, Chicago.
  11. 1 2 Parera, A. (1993) The Neotropical river otter Lutra longicaudis in Ibera Lagoon, Argentina. International Union for the Conservation of Nature, Otter Specialist Group Bulletin. 8:13–16.
  12. 1 2 Munis, M. C., & Oliveira, L. F. B. (2011). Habitat use and food niche overlap by neotropical otter, Lontra longicaudis, and giant otter, Pteronura brasiliensis, in the Pantanal wetland, Brazil. The IUCN/SSC Otter Specialist Group Bulletin, 28(A), 76–85.
  13. 1 2 Alarcon, G. G. & Simones-Lopes, P. C. (2004). "The Neotropical otter Lontra longicaudis feeding habits in a marine coastal area, southern Brazil". IUCN Otter Specialist Group Bulletin. 21 (1): 24–30.
  14. ↑ Lontra longicaudis (Neotropical River Otter) The Online Guide to the Animals of Trinidad and Tobago
  15. ↑ "Lontra longicaudis (Neotropical river otter)". Animal Diversity Web .
  16. ↑ Rheingantz, M. L.; Waldemarin, H. F.; Rodrigues, L. V.; Moulton, T. P. (2011). "Seasonal and spatial differences in feeding habits of the Neotropical otter Lontra longicaudis (Carnivora: Mustelidae) in a coastal catchment of southeastern Brazil". Zoologia (Curitiba, Impresso). 28: 37–44. doi: 10.1590/S1984-46702011000100006 .
  17. 1 2 Arcila, D. A. & Ramirez, M. (2004). Captive reproduction of the Neotropical otter in the Santa Fe Zoological Park in Medellin, Colombia. The IUCN/SSC Otter Specialist Group Bulletin, 2(1), 16–18.
  18. 1 2 3 4 Pardini, R. (1999). "Use of shelters by the neotropical river otter (Lontra longicaudis) in an Atlantic forest stream, southeastern Brazil". Journal of Mammalogy. 80 (2): 600–610. doi: 10.2307/1383304 . JSTOR   1383304.
  19. 1 2 Carrillo-Rubio, E., & Lafon, A. (2004). Neotropical river otter mico-habitat preference in west-central Chihuahua, Mexico. The IUCN/SSC Otter Specialist Group Bulletin, 21(1), 10–15.
  20. ↑ Nakano-Oliveira, E., Fusco, R., Dos Santos, E. A. V., & Monteiro-Filho, E. L. A. (2004). New information about the behavior of Lontra longicaudis (carnivora: Mustelidae) by radio-telemetry. The IUCN/SSC Otter Specialist Group Bulletin, 21(1), 31–35.
  21. ↑ Rheingantz, M. L., Waldemarin, H. F., & Kasper, C. B. (2004). Survey of Neotropical otters: testing methods to access distribution. The IUCN/SSC Otter Specialist Group Bulletin, 21A, 1
  22. ↑ Chehebar, C. (1990). Action plan for Latin American Otters. pp. 63–74 in Otters: an action plan for their conservation Pat Foster-Turley, S. M. Macdonald, Chris Mason (eds.), IUCN/SSC Otter Specialist Group.
  23. ↑ Barbieri, F.; Machado, R.; Zappes, C. A.; Oliveira, L. R. D. (2012). "Interactions between the Neotropical otter (Lontra longicaudis) and gillnet fishery in the southern Brazilian coast". Ocean & Coastal Management. 63: 16–23. Bibcode:2012OCM....63...16B. doi:10.1016/j.ocecoaman.2012.03.007.

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