Some Analyses and Recommendations on Diet Formulation for Conservation Breeding of the Galapagos Rice Rat of Isla Santiago, Nesoryzomys swarthi

摘要

Nesoryzomys swarthi, the most endangered of the three surviving, endemic Galapagos "rice rats," was only discovered in the early 20th Century and was considered extinct until its rediscovery in 1997 at a north-central coastal location on Isla Santiago. Potential threats to the entire genus include invasive rodent species, feral cats, new diseases, and climate change. These threats have been the basis for conservation breeding recommendations (as yet unmet) by several observers during the last several decades. This paper considers likely dietary requirements of N. swarthi in light of recent studies on the ecology of this species plus new data on the nutrient composition of Opuntia galapageia (a "resource refuge" for this species) and circulating vitamin values of animals sampled on Isla Santiago. It is concluded that, despite some unusually high mineral values for O. galapageia, a diet for N. swarthi under human care should be the same as it is for most other rodents, noting some caution in regard to possible needs for mineral and/or protein adjustment.