Neotropical river otter

The neotropical otter or neotropical river otter (Lontra longicaudis) is an otter species found in Central America, South America and the island of Trinidad. It is physically similar to the northern and southern river otter, which occur directly north and south of this species' range. The length of the neotropical otter can range from 90–150 centimetres (35–59 in), of which the tail comprises about a third. Body weight ranges from 5–15 kilograms (11–33 lb). Otters are members of the family Mustelidae, the most species-rich (and therefore diverse) family in the order Carnivora. This otter is found in many different riverine habitats, including deciduous and evergreen forests, savannas, llanos and pantanal. It prefers to live in clear fast-flowing rivers and streams. It is a relatively solitary animal and feeds mostly on fish and crustaceans. 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 interesting phylogenic relationship to other otter species. They are most similar to Lontra feline and Lontra provocax, which is not surprising considering these two species are found in South America. However, neotropical otters are relatively distantly related to Pteronura brasiliensis, which is surprising considering they have nearly identical ecological niches and home ranges. In one study, otters within a 1,600 square mile 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: The neotropical otter is covered in a short, dark grayish-brown pelage. Fur color is lighter around the muzzle and throat. 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. Body mass of the otter generally ranges from 5 to 15 kilograms. Neotropical otters will communicate with nearby otters via scent marking. Communication may also occur via whistles, hums, and screeches. The dental formula seldom varies from that of Eurasian otters, except in the few cases of otters that have dental anomalies. Females and males have the same formula. The dental formula (for half the skull) is as follows: 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 and fast-flowing rivers and are rarely known to settle in the sluggish, silt-laden lowland rivers. While mostly occurring at 300 to 1500 m above sea level they have been found settled at 3000 m. They require abundant riparian vegetation and abundant den sites, but other than that the neotropical otter is very versatile and tolerant to environmental change. The otter will prefer sites that are solid, high, dry, and in proximity to deep water. The Neotropical otter is the greatest generalist of all otter species. It can inhabit formidable habitats such as wastewater treatment plants, rice and sugar cane plantations, drainage ditches, and swamps. It can inhabit cold, glacial lakes in the Andes of Ecuador. It can also live on the shorelines of marine environments hunting marine species and playing in the highly saline water.