Cotton rat (Sigmodon toltecus) as part of the diet of the Neotropical otter (Lontra longicaudis annectens)

Abstract

There are few records of rodents in the diet of Lontra longicaudis annectens in México; only 2 references report the species.  The objective of this note was to analyze the feeding habits of the Neotropical otter in Las Coloradas Lagoon, adjacent to the Palizada River, Campeche, and report the occasional consumption of cotton rats (Sigmodon toltecus).  A distance of 6.63 km was traveled in a boat with an outboard motor along the west side of the lagoon (2.21 km / 2017–2018 climate season).  Spraints and food remains from feeding sites were collected.  Subsequently, the percentage of occurrence (PO) of the prey species consumed was determined.  Ten zoological groups were identified from 176 spraints and 4 feeding sites: fish had the highest PO (36.74 %), followed by gastropods (26.17 %), prawns (11.58 %), crabs (8.56 %), insects (8.05 %), reptiles (5.37 %), birds (2.85 %), mammals (0.34 %), and bivalves and isopods (0.17 % each).  Two skulls and 2 mandibles of S. toltecus were recorded in the 2018 dry season.  Ten of the 14 species of cotton rats, Sigmodon, are recognized in México, of which 1 species (S. toltecus) is reported for the state of Campeche.  This note reports the first record of rodent predation by L. l. annectens in the river-lagoon systems of Campeche.  This occasional record expands the trophic spectrum of the Neotropical otter and the distribution of S. toltecus in the Laguna de Términos Natural Wildlife Protection Area (APFFLT, in Spanish) and the state of Campeche.