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Neotropical River Otters

The neotropical river otter (Lontra longicaudis) is a near-threatened species of otter that ranges from northern Argentina to northern Mexico. Relatively little is known about this species, especially in the most northern part of its distribution in the Rio Yaqui Watershed of eastern Sonora, Mexico. They are difficult to observe and research because they are extremely elusive and many of the rivers of the Rio Yaqui Watershed are accessible only by horseback or raft. 


Primero Conservation began a pilot monitoring project in May of 2018 to determine if an otter monitoring program was feasible in this rugged watershed. Six motion-sensor game cameras were set along the Rio Bavispe and Rio Aros. Three pictures of otters were recorded and one otter was observed by kayak during a survey of the Rio Bavispe south of Granados, Sonora. Additionally, ocelots, mountain lions, and waterfowl were observed on these otter-specific cameras. Based on the pilot project and the lessons learned, we believe that using a combination of cameras and river surveys is appropriate for a standardized otter monitoring program in the Rio Yaqui Watershed.

Neotropical river otters face many threats across their range and within the Rio Yaqui Watershed including increased mining, agricultural pesticides and herbicides, invasive species, and dams. There is little to no data on the population status of neotropical river otters and their natural history in Sonora, Mexico. Without this basic knowledge, it is unknown what conservation actions should be the highest priority.


  • What are the threats to neotropical river otters in the Rio Yaqui Watershed?

  • What are the population trends, size, distribution, and diet of neotropical river otters in the Rio Yaqui Watershed?

  • What conservation actions need to be taken and what are the conservation priorities?

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