Critics of the Act have noted that despite its goal of recovering species so they are no longer listed, this has rarely happened. In its almost 50-year history, less than fifty species have been delisted due to recovery. Indeed, since the passage of the ESA, several species that were listed have gone extinct. Many more that are still listed are at risk of extinction.  This is true despite conservation measures mandated by the Act. As of January 2020 the Services indicate that eleven species have been lost to extinction. These extinct species are the Caribbean monk seal, the Santa Barbara song sparrow; the Dusky seaside sparrow; the Longjaw cisco; the Tecopa pupfish; the Guam broadbill;  the Eastern puma; and the Blue pike.