Another Exotic animal that eats the exotic invasive plants is the Nutria (Myocastor coypus), which is a beaver-sized rodent that is native to South America. In the 1930's, nutria were brought to Louisiana for a fur-farming operation and subsequently were liberated in substantial numbers by hurricanes and accidental escapes. They quickly colonized and spread through-out the Louisiana marshes.
Nutria were not reported as exotics in Florida, until the 1950's, when the first of these animals were found in the Panhandle, the Apalachicol & Choctawhatchee river basins, and in Hillsborough River drainage near Tampa Bay.
In 1972, the Game & Fresh Water Fish Commission, found nutria living in ponds and along canals at several large dairy farms. These farms had several series of pollution polishing ponds and canals to trap and settle out organic waste and for the run-off from the dairy's 1,000-3,000 head of cows.
Exceedly high numbers of nutria were thriving and living there with no apparent ill-effects in these manure sewage lagoons. It was noted that these animals were capable of living and thriving, and breeding in high numbers in these areas.
The fertilizing effect of dairy runoff produces a growth of shoreline vegetation which the nutria utilize heavily on a year round basis. And in addition these lagoons and canals are normally chocked and blocked by dense carpets of water hyacinths. Farmers use the water hyacinths to help cleanse the pollution from the sewage run-off and the nutria feed on the young tender shoots of the hyacinth plants.
In Florida, the adult female nutria breed on a year round basis. All the females collected during a 12 month period were pregnant or lactating. This contrasted with the breeding cycle in Louisana, marshes where there is a single main breeding cycle season in December & January, and a smaller one in June & July. The average litter size at the dairy farms was found to be 5-7 embryos, and a littler size of 3-10 young. The pregnancy lasts about 129-139 days.
With the length of gestation it suggests that a continious breeding cycle under unlimiting environmental conditions produces 2.7 littlers born per adult female every single year. In Florida, the nutria the conditions would represent a total maxinum breeding potential which would average about 15 young per adult female per year. And it was noted that the young mortality rates were very small.
In repect this means that nutria are an exotic species that thrives well in the Florida wilds. Perhapes the exotic pythons rodent feeding will make a dent in the nutria colonies.
